High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Correlation matrices were used to demonstrate co-occurrence of deviant speech dimensions observed. Application of this technique led to the emergence of eight distinctive clusters of dysfunction. Each of seven neurologic disorders studied had its own unique group or pattern of clusters. However, any one cluster emerged in and was shared by more than one disorder. Inspection of the dimensions present in a cluster permitted giving the cluster a logically determined name based usually on the defective physiology responsible for the cluster. Knowledge of the neuromuscular characteristics of each disorder led to deductions concerning the neuromuscular substrate for each cluster. Intercluster correlations yielded clues concerning co-occurrence of certain neuromuscular defects. Further inspection led to identification of the probable neuromuscular bases of individual deviant speech dimensions. These conclusions may serve as hypotheses for more accurate physiologic and neurophysiologic measurements to further del... <s> BIB001 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Thirty-second speech samples were studied of at least 30 patients in each of 7 discrete neurologic groups, each patient unequivocally diagnosed as being a representative of his diagnostic group. Three judges independently rated each of these samples on each of 38 dimensions of speech and voice using a 7-point scale of severity. Computer analysis based on the means of the three ratings on each patient on each dimension yielded results leading to these conclusions: (1) Speech indeed follows neuroanatomy and neurophysiology. There are multiple types or patterns of dysarthria, each mirroring a different kind of abnormality of motor functioning. (2) These patterns of dysarthria can be differentiated; they sound different. They consist of definitive groupings of certain dimensions of speech and voice, deviant to distinctive degrees. (3) Five types of dysarthria were delineated: flaccid dysarthria (in bulbar palsy), spastic dysarthria (in pseudobulbar palsy), ataxic dysarthria (in cerebellar disorders), hypokine... <s> BIB002 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract As an extension of previous findings that Parkinson patients have alterations on tasks relating to body orientation, 54 patients were compared with 36 age-matched controls on the non-verbal portion of the Weinstein [1] body scheme task. Patients with predominantly right-sided symptoms and those with non-lateralized symptoms made significantly more total errors than the controls. Analysis of the error distributions indicated that patients with inferred right hemisphere damage and those with inferred bilateral damage tended to make significantly more bilateral errors than the normals; those patients with inferred left hemisphere damage differed from the controls only when required to point to contralateral body parts with the stimulus figure in the opposite orientation. <s> BIB003 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract An extensive set of neuropsychological measures was administered to 60 Parkinson's disease patients and age-, sex-, and education-matched controls in order to investigate the nature and prevalence of the cognitive deficit in the disease. Parkinsonian patients performed significantly poorer on all measures with the exception of tests for apraxia and object recognition, and on a test of vocabulary knowledge. Discriminant analysis of the test data revealed that over 93% of patients are impaired relative to matched controls, but that assigning a prevalence rate for dementia in the disease may be difficult due to the continuous distribution of cognitive deficits. <s> BIB004 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Neuropsychological tests known to reveal abnormalities in patients with frontal lobe damage were used to explore cognitive function in 30 mildly disabled, right-handed patients with idiopathic Parkinson's disease. None of the patients had received treatment and all had normal CT brain scans. Patients with depression or high ischaemia scores were excluded from the study and similar selection criteria were used for the age-matched controls. No impairment of general intellectual function was found in the patients using the WAIS and New Adult Reading IQ tests and no abnormalities were apparent on cognitive estimates and two-choice Recognition Memory Tests. Patients with Parkinson's disease, however, had significantly greater difficulty in shifting conceptual sets and produced more perseverative errors on both the modified Wisconsin Card Sorting Test and Benton's Word Fluency Test. These subtle cognitive difficulties might underlie the mental inflexibility and rigidity of Parkinson's disease and could be attributed to destruction of the ascending dopaminergic meso-corticolimbic pathway <s> BIB005 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The current paper explains a model of subcortical language functions that focuses on dynamic interactions between the cortex, the thalamus, and the basal ganglia in the production of spoken language. The model was derived from (a) studies of subcortical lesions and language, (b) studies of subcortical stimulation and language, (c) knowledge regarding neural pathways between various cortical and subcortical structures, and (d) indications that preverbal monitoring of language occurs. In the current model, the thalamus plays roles in cortical arousal and activation and in preverbal semantic monitoring. The basal ganglia function to regulate the degree of excitation conveyed from the thalamus to the cortex and to time the release of formulated language for motor programming. Consistency with classical syndromes of aphasia and potential applications to other areas in the neurosciences are discussed. The current theory, unlike previous formulations, is specific enough that testable hypotheses can be derived. <s> BIB006 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The reliability of primitive reflexes as monitors of dementia, depression, and severity of Parkinson's disease were studied. The results indicated that the proportion of certain reflexes increased with severity of disease and cognitive impairment, but no relationship was seen between any of the reflexes and degree of depression. <s> BIB007 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Estimates of the prevalence of dementia in patients with Parkinson's disease (PD) vary considerably. Dementia in PD has been linked to a visuospatial disturbance, impairment of memory, and depression. Previous research suggests that visuospatial deficits and depression do not vary with severity of intellectual decline and thus are not useful measures to distinguish demented from nondemented patients. We examined immediate, recent, and remote memory in patients with PD and found that unlike visuospatial performance and depression, a qualitatively distinct pattern emerged, which did vary with severity of intellectual decline. <s> BIB008 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> We have analysed the aphasia profiles of 19 cases with subcortical infarction or haemorrhage. Several components of the aphasic syndromes, especially sentence length and grammatical form (together compromising fluency), ease of speech initiation, articulation, voice volume, and auditory comprehension, were individually isolated for correlation with CT lesion site. Each component had a specific lesion site correlation, and lesions in various deep periventricular white matter regions were the critical ones for all components of aphasia. Simple tabulation of lesions as cortical or subcortical, and restricting analysis to lesions of basal ganglia would both have proved inadequate to account for clinical findings. A review of 61 subcortical cases in the neurological literature for which CT and aphasia data were available supports these conclusions. <s> BIB009 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Speech and language alterations were assessed in 51 patients with Parkinson9s disease (PD) and 10 patients with dementia of the Alzheimer type (DAT). Thirty-five of the PD patients had no evidence of intellectual impairment on a conventional mental status questionnaire and 16 of the PD patients had dementia syndromes of comparable severity to the DAT patients. DAT produced significantly greater language disturbances, including anomia, decreased information content of spontaneous speech, and diminished word list generation. PD patients had significantly decreased phrase length, impaired speech melody, dysarthria, and agraphia. The results suggest that the dementia of PD is distinguishable from that of DAT: PD patients have prominent motor speech abnormalities, whereas DAT patients exhibit more profound language alterations. <s> BIB010 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract The hypokinetic dysarthria of Parkinson's disease (PD) has been described extensively. In contrast, patterns of hesitation and the language structure in spontaneous speech of the PD patient have not been investigated, although several studies have shown language-related abnormalities in word naming, word generation, and verbal recall. In the present study, 10 male Parkinson's patients and 10 normal male speakers were compared in a reading and spontaneous speaking paradigm for acoustic and linguistic features. Among acoustic measures, fundamental frequency and relative intensity differentiated PD from control subjects, consistent with reported features of hypokinetic dysarthria. The striking observations among linguistic measures differentiating PD from control subjects were an increase in the number of (a) silent hesitations per minute, (b) abnormally long silent hesitations, (c) words per silent hesitation, (d) open class phrases, and (e) optional open phrases per speech sample, and a decrease in the number of modalizations and interjections. An increase in the number of filled hesitations occurring per minute, as well as a decrease in syntactic complexity separated moderate from mild Parkinson's patients. Our interpretation of the data favors the hypothesis that changes in the structure of spontaneous language production with increasing severity of dysarthria reflect PD patients' adaptation to their disease. <s> BIB011 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> We administered a battery of cognitive tests to 41 recently diagnosed Parkinson patients and 41 controls to assess the early neuropsychological changes associated with Parkinson's disease (PD). Parkinson subjects did as well as controls on tasks assessing attention and select language and visuospatial measures. However, PD subjects did significantly worse on embedded figures, facial recognition, proverbs, and verbal and figural memory measures, and made more perseverative responses on a set shifting task. A discriminant function of measures of proverbs, embedded figures, and memory accounted for 22% of the variance between groups. These data suggest that the cognitive changes in early PD are more pervasive than originally described and may reflect the onset of a more widespread pathologic process. <s> BIB012 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract An analysis of the temporal (prospective) form (silent and filled hesitations, repetitions, incomplete phrases, context-related comments, interjections), syntactic form, and lexical (retrospective) form (verbal deviations, open and closed class phrases) of spontaneous language production of early and middle stage Alzheimer's, Huntington's, and Parkinson's patients was made. Results showed that the language structure was disrupted in each disease, but in different ways. Temporal interruptions of varying types were frequent in the language of Alzheimer's and Huntington's Disease patients; only long-duration silent hesitations were frequent in Parkinson's language samples. Syntactic complexity was reduced in Huntington's Disease. Verbal paraphasias were found in both the language of Alzheimer's patients, as well as moderately advanced Huntington's patients. Closed class phrases were predominant in the language of Alzheimer's patients and Huntington's patients, and open class phrases in the language of Parkinson's patients. Taken together, the results suggest that (1) there is a unique neurolinguistic profile for spontaneous language production for each neurodegenerative disease, (2) pathology of the neostriatum disrupts syntactic organization, (3) adaptive strategies are used to cope with verbal and speech-motor difficulties, and (4) adaptive strategies fail to be effective with increasing disease severity. <s> BIB013 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> To test the hypothesis that the cognitive impairments that accompany Parkinson's disease (PD) arise from frontal lobe dys function, patients with idiopathic PD and controls were tested on a neuropsychological battery that included measures of anterograde memory, visuospatial perception, and naming, as well as several tests that are known to be sensitive to lesions of the frontal lobes. PD patients of normal mental status as measured by the Mini-Mental State Examination performed normally on the naming, line orientation, and verbal recognition memory tests but exhibited deficits on verbal recall. On tests of frontal lobe function, these patients showed mild deficits on a category fluency task and on the Wisconsin Card Sorting Test. However, their errors on the latter were not typical of patients with frontal lesions, and they performed nor mally on a letter fluency task and exhibited normal release from proactive interference. Patients of lower than normal mental status performed poorly on nearly all of th... <s> BIB014 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract The utility of the concept of «subcortical dementia» was investigated by comparing the verbal learning and memory abilities of Parkinson's disease (PD) patients with those of Huntington's disease (HD) patients. Many similarities between the PD and HD groups emerged, including impaired immediate memory spans, inconsistency of recall across learning trials, deficient use of a semantic clustering learning strategy, elevated intrusion rates on delayed recall, impaired recognition memory performance, normal retention of information over delay periods, normal vulnerability to proactive or retroactive interference, and normal types of intrusion errors. The HD subjects, however, displayed inferior free recall, deficient improvement across learning trials, abnormal serial position recall effects, higher perseveration rates, and supranormal improvement on recognition testing compared with free recall. Implications of these results for characterizing memory deficits associated with subcortical system dysfun... <s> BIB015 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Twelve patients with idiopathic Parkinson's disease had acoustic speech analysis of sentence utterances to provide information on speech tempo and accuracy of articulation. As a measure of rate of speech the duration of opening-closing movements during articulation was determined from speech wave variables. The intensity of sound emission during articulatory closure as required for stop consonant production, for example, magnitude of p, magnitude of t, magnitude of k, was used as an index of the degree of closure. Speech tempo was not significantly different from normal. The patients, however, had a reduced capacity of completing articulatory occlusion. This was interpreted as reflecting a reduction in movement amplitude of the articulators. Articulatory "undershoot" was not uniform but influenced by linguistic demands in that the closures associated with a stressed syllable were performed at the expense of unstressed ones. Furthermore, switching between opening and closing movements of the articulators in sentence production seemed undisturbed. These results indicate that motor planning of speech differs from arm movement control. <s> BIB016 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> It is now recognized that many patients with Parkinson’s disease will experience cognitive and intellectual decline in the course of their illness. Selective visuospatial and memory impairment, executive dysfunction, slowed information processing, and depression are consistently observed in a high proportion of patients. Language abilities appear to be relatively spared. Current age, age of onset, disease duration, and predominant motor symptoms all exert important differential effects on the expression of the dementing process. Although these patterns point to a subcortical origin, it is probable that Parkinson’s disease is composed of several dementia syndromes. <s> BIB017 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> There has been disagreement about the precise characteristics of "subcortical aphasia." We evaluated 14 patients with aphasia after subcortical lesions and controlled for duration, general anatomic site of lesions (capsulostriatal only), and etiology. The clinical profiles of the patients were quite similar, varying in severity in rough proportion to lesion size and varying in quality in proportion to anterior paraventricular extent. Large lesions were associated with impaired "executive" and "generative" language functions. Similar aphasia profiles in patients with deep frontal and paraventricular white matter lesions suggest that damage to a frontal-caudate functional system underlies a "core" aphasia profile in these patients. <s> BIB018 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract A time-based approach to agrammatic speech is presented, The paper consists of three parts. In the first part, the literature which deals with agrammatic comprehension as a problem of disrupted timing, that is, as a slow-down of syntactic computation and/or a rapid decay of the results of syntactic processing, is reviewed. In a second part, the hypothesis that similar timing problems cause difficulties in production as well is discussed. Two possible ways in which this can happen are described, First, slow down or rapid decay can lead to desynchronization within the process of syntactic tree formation. Second, a slow down of syntactic processing can cause asynchrony between the production of a syntactic slot and the retrieval of the proper grammatical morpheme from the mental lexicon. This hypothesis predicts that morphemes which are dependent on a relatively complex part of the syntactic tree will elicit relatively many errors. Results from the literature which seem to confirm this prediction are discussed. In the third part of the paper, the possible ways in which a patient can adapt to the reduced temporal window that would result from a timing deficit are discussed. Message simplification will reduce the size of the required temporal window and will therefore have a beneficial effect on the error rate. Restart of the computational process will profit from previously reached activation levels so that synchrony is easier to reach and error rate is reduced, Empirical work which appears to support these hypotheses is reviewed. <s> BIB019 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> OBJECTIVE--To determine whether a deficit of the central executive can explain the attentional deficits of patients with Parkinson's disease. METHODS--Fifteen patients with idiopathic Parkinson's disease and 15 controls were given a dual task paradigm minimising motor demands and combining verbal, visual, or spatial span with two conditions of articulatory suppression. RESULTS--Although the spans were systematically lower in medicated parkinsonian patients than in controls, suggesting a decrease of central processing resources, there was no direct evidence for a deficit of the central executive. CONCLUSIONS--A deficit of the central executive either is not an inevitable feature of the disease, or is dependent on the nature of task (visuomotor v cognitive), or is corrected by dopaminergic medication. <s> BIB020 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract This study examined the grammatical content of written sentences elicited from 96 Parkinson's patients, 30 Parkinson's with dementia patients and 167 control subjects. Parkinson's patients without dementia or with mild dementia presented no impairments in sentence length, syntactic complexity or amount of information content. Moderately demented Parkinson's patients showed reduced sentence length and information content but normal syntactic complexity. This pattern of results provides evidence that lexical-semantic content is more susceptible to decline than syntactic structure with the progression of dementia in Parkinson's disease. <s> BIB021 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> We critically review the literature on subcortical aphasia, suggest that a number of traditional concepts regarding mechanisms of aphasia are inconsistent with now abundant data, and propose several new hypotheses. The absence of aphasia in 17 reported cases of dominant hemisphere striatocapsular infarction and the finding of nearly every conceivable pattern of language impairment in 33 different reported cases of striatocapsular infarction provide strong evidence against a major direct role of the basal ganglia in language and against disconnection or diaschisis as mechanisms of nonthalamic subcortical aphasia. However, detailed consideration of the vascular events leading to striatocapsular infarction strongly suggests that associated linguistic deficits are predominantly related to sustained cortical hypoperfusion and infarction not visible on structural imaging studies. Thalamic disconnection, as may occur with striatocapsular infarcts with extension to the temporal stem and putamenal hemorrhages, may also contribute to the language deficits in some patients. Review of the literature on thalamic infarction, in conjunction with previously unreported anatomic details of four cases, suggests that what infarcts in the tuberothalamic artery territory and the occasional infarcts in the paramedian artery territory associated with aphasia have in common is damage to the frontal lobe-inferior thalamic peduncle-nucleus reticularis-center median system that may be involved in regulating the thalamic gate in attentional processes. Disruption of attentional gating in the pulvinar and lateral posterior nuclei resulting from such lesions may impair selection of specific neuronal networks in the projection field of these nuclei that serve as the substrate for lexical-semantic function, which is in effect a disruption of a type of working memory, as defined by Goldman-Rakic. We define this as a defect of selective engagement. <s> BIB022 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Deficits in verbal fluency and naming, memory and comprehension of verbal information, as well impairment in verbal and logical reasoning are frequently associated with linguistic performance in Parkinson's disease, a neurodegenerative disorder primarily involving subcortical structures and the depletion of dopaminergic neurons in the substantia nigra. Impairment is more pronounced in more complex aspects of language processing as in sentence comprehension, understanding of relational terms and relative clauses, and in aspects of logical reasoning. It is believed that constraints in accessing the cognitive resources needed to implement the processing of syntactic and semantic information, as well as the disruption of reciprocating neural connections between the basal ganglia with the prefrontal cortex, may explain these observed deficits. <s> BIB023 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The purpose of this study was to investigate the presence and nature of spoken language deficits in Huntington's (HD) and Parkinson's (PD) diseases. Specifically, the study examined whether (a) the... <s> BIB024 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> A cross-modal priming experiment was used to investigate lexical ambiguity resolution during sentence processing in individuals with nonthalamic subcortical lesions (NSL) (n = 10), compared to matched normal controls (n = 10), and individuals with cortical lesions (CL) (n = 10) and Parkinson's disease (PD) (n = 10). Critical sentences biased towards the dominant or subordinate meaning of a sentence-final lexical ambiguity were presented auditorily, followed after a short interstimulus-interval (ISI) (0 msec) or a long ISI (1000 msec). by the presentation of a visual target which was related to the dominant or subordinate meaning, or was an unrelated control word. Subjects made speeded lexical decisions on the targets. At the short ISI, lexical activation for the neurological patient groups appeared influenced by contextual information to a greater extent than in normal controls, which may indicate delayed lexical decision making or disturbed automatic lexical activation. At the long ISI, only the PD and NSL individuals failed to selectively activate the contextually appropriate meaning, suggesting a breakdown in the attention-based control of semantic activation through contextual integration. This finding may implicate disruptions to proposed frontal-striatal mechanisms which mediate attentional allocation and strategy formation. <s> BIB025 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Parkinson's disease is a widespread degenerative illness affecting the human central, peripheral, and enteric nervous systems. The underlying pathological process progresses slowly but relentlessly and involves multiple neuronal systems. The disease is the consequence of changes in the neuronal cytoskeleton developing in only a few susceptible types of nerve cells. Afflicted neurons eventually produce Lewy bodies in their perikarya and Lewy neurites in their neuronal processes. Immunoreactions against the presynaptic protein alpha-synuclein have revealed many kinds of inclusion bodies ranging from inconspicuous dot- or thread-like forms to particularly voluminous types. The selective vulnerability of nerve cells induces a distinctive distribution pattern of lesions which remains remarkably consistent across cases. Components of the limbic system and the motor system have been shown to be particularly vulnerable to severe destruction. Some subnuclei of the substantia nigra also undergo major changes. This damage is consistently accompanied by extranigral alterations, with predilection sites including the entorhinal region, the second sector of the Ammon's horn, and important subnuclei of the amygdala. In addition, the nucleus of the stria terminalis, components of the hypothalamus, all of the non-thalamic nuclei with diffuse projections to the cerebral cortex, and most of the centers regulating autonomic functions exhibit severe lesions. <s> BIB026 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Cooper, Sagar, Jordan, Harvey, and Sullivan (1991) proposed a Digit Ordering Test (DOT) for the assessment of verbal working memory: A series of seven digits has to be memorized and immediately recalled in ascending order. In several studies Cooper and co-workers showed selectively reduced DOT performance in patients with Parkinson's disease (PD). We present results from three studies on the properties of this test. In study 1 we replicated the original findings and evaluated a new scoring method. Study 2 addressed the psychometric features of the DOT and provides normative data based on a total of 134 test protocols (PD: 18, other neurological patients: 60, healthy controls: 56). In study 3 we used an experimental modification of the test (DOT-EXP) to evaluate the effects of the presentation rate on serial recall and digit ordering performance. The standard presentation rate of seven digits in 5 s was confirmed as most sensitive for detection of verbal working memory deficits. Findings confirmed that the... <s> BIB027 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Although sentence production is more common than single‐word production in daily life, acoustic and intelligibility data from persons with neurogenic speech disorders is largely limited to single‐word and target‐word utterances. The purpose of the current study is to examine sentence productions of individuals with Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS), and to compare them to data obtained from neurologically normal individuals. Each speaker produced multiple repetitions of a small set of sentences. Acoustic measures included overall sentence durations, segment durations, and vowel formant frequencies. Speech intelligibility of the sentences was measured using scaling techniques. For some subjects, previously obtained acoustic and intelligibility data for single words will be related to the findings for sentences. Results will be discussed descriptively as deviations from patterns observed in normal individuals, and in terms of associations between the acoustic and intelligibili... <s> BIB028 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> This study examined syntactic changes in the spoken discourse of patients with Huntington's (HD) or Parkinson's disease (PD) and explored possible relationships between their syntactic changes and concomitant cognitive and motoric symptoms. Patient and control groups participated in a conversational discourse activity and completed a battery of standardized speech and cognitive tests. The HD group used shorter and fewer grammatically complete utterances than their healthy, age-matched peers, whereas there were no significant syntactic differences between PD patients and their healthy, age-matched peers or between PD and HD patients. Productive syntax abilities in HD and PD were meaningfully related to both neuropsychological and motor speech changes. These findings indicate that patients with subcortical disease, at least those with HD, may present with language production deficits and that these deficits are most likely the product of not only motor speech limitations (i.e., dysarthria) but also underlying cognitive impairments. <s> BIB029 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract Patients with Parkinson's disease (PD) have sentence comprehension difficulty, but it is unclear whether this is due to a deficit in grammatical processing or to an executive resource limitation. To assess grammatical processing in PD while minimizing task-related demands, PD patients and healthy control subjects performed a word detection procedure that assesses sensitivity to grammatical agreements in sentences in an “on-line” fashion. With this technique, we found that control subjects and PD patients are equally sensitive to grammatical agreement violations in sentences. A traditional, resource-demanding measure of sentence comprehension was also administered to the same PD patients. In comparison to healthy controls, PD patients were significantly impaired in their relative comprehension of sentences containing object-gap subordinate clauses compared to subject-gap subordinate clauses. Performance on several executive resource measures was also impaired in PD, and this correlated with their comprehension performance. Sensitivity to grammatical agreements with the word detection procedure, in the context of sentence comprehension difficulty on a traditional measure, suggests that PD patients' executive resource limitations contribute to their sentence comprehension difficulty. <s> BIB030 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> It has been suggested that in patients with Parkinson’s disease (PD), difficulties in the manipulation of information, which result in problems in executive tasks, are related to a reduction of working memory capacity (J. D. E. Gabrieli, J. Singh, G. T. Stebbins, & C. G. Goetz, 1996). The present study selectively varied the manipulation demand irrespective of the maintenance requirement. In a group of 14 PD patients, performance declined overproportionally with the increasing task demand and was significantly correlated with a measure of working memory capacity. These results suggest that the complexity of working memory processing may decisively contribute to the exhaustion of resources in PD patients. Increasing complexity may either affect their manipulation ability directly or impede the management of inhibitory control requirements inherent to the task. <s> BIB031 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> In the face of ample experimental evidence on the importance of working memory capacity for everyday life, there is a growing need for measures suited for clinical assessment of working memory. For this purpose, the Adaptive Digit Ordering Test (DOT-A), a new version of a digit ordering test introduced by Cooper et al. [Brain 114 (1991) 2095], was developed in analogy to the Digit spans. In Study 1, we investigated DOT-A performance in patients with Parkinson’s disease (PD) and patients with frontal lobe damage, as these groups often exhibit working memory impairments within the framework of executive dysfunctions. In comparison with matched controls, both patient groups showed reduced performance in DOT-A but not in Digit span performance. This pattern was found to be particularly sensitive for patients with PD. In Study 2, DOT-A performance was assessed in 50 healthy subjects carefully selected according to demographic criteria in order to ensure representativity. Parallel test and split-half correlations indicated sufficient reliability of the DOT-A. Concurrent validity was confirmed by significant correlation with a well-established working memory test (two-back task). We conclude that DOT-A is a promising diagnostic instrument, and its economy and direct comparability to the <s> BIB032 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> This study tests the hypothesis that sentence comprehension difficulty in Parkinson's disease (PD) is related in part to altered information processing speed that plays a crucial role in grammatical processing. The authors measured information processing speed in 32 PD patients without dementia using a lexical list-priming paradigm in which the interstimulus interval (ISI) between the prime and the target varied. Sentence comprehension accuracy was also assessed in 22 of these patients. Sentence comprehension accuracy for object-relative center-embedded sentences was impaired in a subgroup of PD patients. This subgroup of PD patients primed at an abnormally long ISI. Similarly, only PD patients who primed at a long ISI had greater difficulty understanding sentences with an object-relative clause than a subject-relative clause. Findings suggest that slowed information processing speed contributes to sentence comprehension difficulty in PD. <s> BIB033 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Twenty-six subjects with idiopathic Parkinson's disease (PD) and normal cognitive status (as measured by the Mini-Mental State Examination) were examined with a battery of tests selected to reveal subtle and/or high-level language impairments. The test battery included 'repetition of long sentences', 'recreating sentences', 'making inferences', 'comprehension of logico-grammatical sentences', 'comprehension of ambiguous sentences' and 'comprehension of metaphors', 'word definitions', 'word fluency', 'naming', 'sentence analysis' and 'morphological completion'. Comparisons were made between the PD subjects and 26 control subjects matched for age, gender and level of education. Significant differences in performance between the PD subjects and the control subjects were found in the ability to make inferences and to analyse sentences (state the correct number of words in a read sentence). An additional four subjects with different degrees of cognitive dysfunction were also investigated and were found to have... <s> BIB034 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The impact of basal ganglia dysfunction on semantic processing was investigated by comparing the performance of individuals with nonthalamic subcortical (NS) vascular lesions, Parkinson’s disease (PD), cortical lesions, and matched controls on a semantic priming task. Unequibiased lexical ambiguity primes were used in auditory prime-target pairs comprising 4 critical conditions; dominant related (e.g., bank‐money ), subordinate related (e.g., bank‐river), dominant unrelated (e.g., foot‐money) and subordinate unrelated (e.g., bat‐river). Participants made speeded lexical decisions (word0nonword) on targets using a go‐no-go response. When a short prime‐target interstimulus interval (ISI) of 200 ms was employed, all groups demonstrated priming for dominant and subordinate conditions, indicating nonselective meaning facilitation and intact automatic lexical processing. Differences emerged at the long ISI (1250 ms), where control and cortical lesion participants evidenced selective facilitation of the dominant meaning, whereas NS and PD groups demonstrated a protracted period of nonselective meaning facilitation. This finding suggests a circumscribed deficit in the selective attentional engagement of the semantic network on the basis of meaning frequency, possibly implicating a disturbance of frontal‐subcortical systems influencing inhibitory semantic mechanisms. (JINS, 2003, 9, 1041‐1052.) <s> BIB035 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The 1990s were dubbed the “Decade of the Brain.” During this time there was a marked increase in the amount of neuroimaging work observing how the brain accomplishes many tasks, including the processing of language. In this chapter we review the past 15 years of neuroimaging research on language production and comprehension. The findings of these studies indicate that the processing involved in language use occurs in diffuse brain regions. These regions include Broca's and Wernicke's areas, primary auditory and visual cortex, and frontal regions in the left hemisphere, as well as in the right hemisphere homologues to these regions. We conclude the chapter by discussing the future of neuroimaging research into language production and comprehension. <s> BIB036 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The relations between dual-task effects and aging were examined through a meta-analysis of 33 studies (with 48 independent participant groups) using latency as the dependent measure and 30 studies (with 40 independent participant groups) focusing on accuracy. Brinley plots and state traces were derived, and a model to explicate different types of complexity (additive and multiplicative) was developed. The effects of dual-task processing on latency were additive, and this additive cost was larger in older adults than in younger adults and larger than predicted from general slowing. This cost was small and independent of task complexity. The effects of dual-task processing on logit-transformed accuracy were likewise additive, but no specific age deficit was associated with this dual-task cost. <s> BIB037 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> BackgroundSentence comprehension requires linguistic processing as well as cognitive resources such as working memory (WM) and information-processing speed (IPS). The authors hypothesize that sentence comprehension difficulty in patients with mild PD is due to degradation of the large-scale neural network that supports cognitive resources during sentence processing. ObjectiveTo understand the neural basis for sentence comprehension difficulty in PD. MethodRegional brain activity with blood oxygenation level–dependent fMRI was monitored while seven PD patients and nine healthy seniors answered a simple probe about written sentences that vary in their grammatical and cognitive resource properties. ResultsHealthy seniors recruited posterolateral temporal and ventral inferior frontal regions of the left hemisphere, brain regions associated with grammatical processing that were also activated by PD patients. Healthy seniors also recruited left dorsal inferior frontal, right posterolateral temporal, and striatal regions that are associated with cognitive resources during sentence processing. Direct contrasts showed that striatal, anteromedial prefrontal, and right temporal regions are recruited to a significantly lesser degree in PD, but these patients have increased activation of right inferior frontal and left posterolateral temporal–parietal areas during sentence comprehension. ConclusionThese findings associate impaired sentence comprehension in PD with interruption of a large-scale network important for cognitive resources during sentence processing. These results also imply compensatory up-regulation of cortical activity that allows patients with mild PD to maintain sentence comprehension accuracy. <s> BIB038 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The synucleinopathy, idiopathic Parkinson's disease, is a multisystem disorder that involves only a few predisposed nerve cell types in specific regions of the human nervous system. The intracerebral formation of abnormal proteinaceous Lewy bodies and Lewy neurites begins at defined induction sites and advances in a topographically predictable sequence. As the disease progresses, components of the autonomic, limbic, and somatomotor systems become particularly badly damaged. During presymptomatic stages 1-2, inclusion body pathology is confined to the medulla oblongata/pontine tegmentum and olfactory bulb/anterior olfactory nucleus. In stages 3-4, the substantia nigra and other nuclear grays of the midbrain and forebrain become the focus of initially slight and, then, severe pathological changes. At this point, most individuals probably cross the threshold to the symptomatic phase of the illness. In the end-stages 5-6, the process enters the mature neocortex, and the disease manifests itself in all of its clinical dimensions. <s> BIB039 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Patients with Parkinson9s disease (PD) exhibit impairments in several cognitive functions similar to those observed in patients with prefrontal cortex (PFC) lesions. The physiological origins of these cognitive deficits are not well documented. Two mechanisms have been proposed: disruptions in corticostriatal circuits or a deficiency in frontal dopamine. We previously used functional magnetic resonance imaging (fMRI) in young healthy subjects to separate patterns of PFC and striatum activity during distinct phases of performance of the Wisconsin Card Sorting Task, a set-shifting task that reveals deficits in patients with PD. Here, the same fMRI protocol was used in PD patients and matched controls. Decreased activation was observed in the PD group compared with the matched control group in the ventrolateral PFC when receiving negative feedback and the posterior PFC when matching after negative feedback. In controls, these prefrontal regions specifically coactivated with the striatum during those stages of task performance. In contrast, greater activation was found in the PD group compared with the matched control group in prefrontal regions, such as the posterior and the dorsolateral PFC when receiving positive or negative feedback, that were not coactivated with the striatum in controls. These results suggest that both nigrostriatal dopamine depletion and intracortical dopamine deficiency may play a role in cognitive deficits in PD, depending on the involvement of the striatum in the task at hand. <s> BIB040 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract In the first part of this study, we investigated effects of item and task type on span performance in a group of aphasic individuals with word processing and STM deficits. Group analyses revealed significant effects of item on span performance with span being greater for digits than for words. We also investigated associations between subjects’ lexical-semantic and phonological processing abilities and performance on four measures of verbal span (digit and word span, each varied for type of response, verbal vs. pointing) as well as one measure of nonverbal span. We predicted and found that the patterns of association between verbal span tasks and lexical abilities reflected the integrity of language processes and representations deployed in each paradigm used to assess span. Performance on the pointing span task, which engages both lexical-semantic and phonological processes, correlated with measures of both lexical-semantic and phonological abilities. Performance on repetition span, which engages primarily input and output phonological processes, correlated with measures of phonological abilities but not measures of lexical-semantic abilities. However, when partial correlations were performed for two subject groups based on their relative preservation of lexical-semantic ability (less or more than phonological ability), repetition span correlated with lexical-semantic measures only in the subgroup with relatively impaired lexical-semantics. Additionally, performance on the nonverbal span task correlated with measures of phonological abilities, suggesting either a general cognitive deficit affecting verbal and nonverbal STM or possibly, the use of a verbal strategy to perform this task. Our discussion focuses on the interpretation of span measurements in clinical practice and research, as well as the implications of these data for theories of short-term memory and word processing. <s> BIB041 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> It has been known for many years that the classic motor symptoms of Parkinson’s disease are accompanied by deficits of executive function that resemble those seen after frontal lobe damage in humans. What is less clear is how different components of frontostriatal circuitry contribute to these impairments. Recently, improved methods of clinical assessment and classification, combined with novel technical approaches, such as functional neuroimaging, have led to great advances in our understanding of the fundamental mechanisms that drive frontostriatal circuitry. As a direct result, it has been possible to redefine impairments of executive function in Parkinson’s disease more precisely in terms of the specific neuropsychological, neuroanatomical, and psychopharmacological mechanisms involved. <s> BIB042 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Studies of sentence comprehension deWcits in Parkinson’s disease (PD) patients suggest that language processing involves circuits connecting subcortical and cortical regions. Anatomically segregated neural circuits appear to support diVerent cognitive and motor functions. To investigate which functions are implicated in PD comprehension deWcits, we tested comprehension, verbal working memory span, and cognitive set-switching in a non-linguistic task in 41 PD patients; we also obtained speech measurements reXecting motor sequencing processes that may be involved in articulatory rehearsal within working memory. Comprehension of sentences with centerembedded or Wnal relative clauses was impaired when they could not be understood from lexical semantic content alone. Overall comprehension error rates correlated strongly with impaired set-switching and signiWcantly with reduced working memory span and speech motor sequencing deWcits. Correlations with comprehension of diVerent sentence structures indicate that these impairments do not represent a single deWcit; rather, PD comprehension deWcits appear to arise from several independent mechanisms. DeWcits in cognitive setswitching or underlying inhibitory processes may compromise the ability to process relative clauses. DeWcits in verbal working memory appear to impair comprehension of long-distance dependencies. Speech sequencing correlated with neither set-switching nor verbal working memory span, consistent with their being supported by independent, segregated cortico-subcortical circuits. <s> BIB043 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Objective:To determine the frequency and pattern of cognitive dysfunction in patients with newly diagnosed Parkinson disease (PD) and to identify its demographic and clinical correlates. Methods:A cohort of 115 consecutive patients with newly diagnosed PD and 70 healthy controls underwent a comprehensive neuropsychological assessment including tests of psychomotor speed, attention, language, memory, executive and visuospatial functions, as well as measures of affective status. Patients also received quantitative ratings of motor symptom severity and functional status. Neuropsychological performance of PD patients was compared with that of healthy controls and with available normative data. Independent demographic and clinical predictors of cognitive impairment were identified with multiple logistic regression analysis. Results:Relative to controls, PD patients performed significantly worse on most cognitive measures. However, further analysis revealed that group differences in cognitive performance could mainly be explained by measures of immediate memory and executive function. Comparison with normative data showed that impairments were most frequent on measures of executive function, memory and psychomotor speed. In all, 24% of PD patients (4% of controls) displayed defective performance on at least three neuropsychological tests and were classified as cognitively impaired. Late onset of disease was an independent predictor of cognitive dysfunction in PD. Conclusion:Cognitive impairments are common even in newly diagnosed Parkinson disease patients, with deficits being most prominent in the domains of memory and executive functions. Older age at disease onset is likely to be an important determinant of cognitive dysfunction in Parkinson disease. <s> BIB044 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The authors examined the nature of the working memory deficit in persons with Parkinson's disease (PD). Three hypotheses were tested: a limited storage capacity, an impaired executive component, and a reduction of psychomotor speed. Verbal working memory was assessed in 14 PD patients without dementia and 14 matched control participants. Participants were administered a classical verbal span test, working memory tasks that required either updating or manipulation capacities, and motor and psychomotor speed tasks. Patients' performance was comparable to that of control participants on the verbal span test. However, results on the working memory tasks indicated a deficit in manipulation with normal updating capacities. Motor and psychomotor slowing were found in the patient group, but slowing could not fully account for the impairment observed in the manipulation task. Results indicated that there is a genuine but selective working memory impairment in patients with PD. <s> BIB045 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Cognitive function and the performance of a secondary, dual task may affect certain aspects of gait, but the relationships between cognitive function and gait are not well understood. To better understand the motor control of gait and the relationship between cognitive function and gait, we studied cognitive function and the effects of different types of dual tasking on the gait of patients with Parkinson’s disease (PD) and controls, contrasting measures of gait automaticity and rhythmicity with other features. Patients with idiopathic PD (n ¼ 30; mean age 71.8 year) with moderate disease severity (Hoehn and Yahr Stage 2–3) were compared to age and gendermatched healthy controls (n ¼ 28). Memory and executive function were also assessed. In both groups, gait speed decreased in response to dual tasking, in a parallel fashion. For the PD group only, gait variability increased compared to usual walking. Executive function was significantly worse in the PD group, while memory was not different in the two groups. Executive function measures were significantly correlated with gait variability during dual tasking, but not during usual walking. These findings demonstrate that regulation of gait variability and rhythmicity is apparently an automatic process that does not demand attention in healthy adults. In patients with PD, however, this ability becomes attention-demanding and worsens when subjects perform secondary tasks. Moreover, the associations between executive function and gait variability suggest that a decline in executive function in PD may exacerbate the effects of dual tasking on gait, potentially increasing fall risk. <s> BIB046 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> The current study investigated the involvement of all four components of Baddeley's [Baddeley, A. D. (2000). The episodic buffer: A new component of working memory? Trends in Cognitive Sciences, 4, 417–423] revised working memory model in deficits of planning accompanying Parkinson's disease (PD). PD resulted in poorer formulation and execution of plans, as measured by the Tower of London task. PD also reduced the efficiency of the episodic buffer and central executive components of working memory, but did not influence storage of verbal or visuospatial information. Planning deficits in PD were particularly linked to problems in integrating multimodal short-term information with long-term memory (episodic buffer). These results emphasize the importance of integrative and executive processing in cognitive problems in PD, rather than simple memory deficits. <s> BIB047 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Aphasia has traditionally been viewed as a loss or impairment of language. However, evidence is presented suggesting that language mechanisms are fundamentally preserved and that aphasic language behaviors are instead due to impairments of cognitive processes supporting their construction. These processes may be understood as a linguistically specialized attentional system that is vulnerable to competition from other processing domains. We present two models of attention that focus on competition for central processing and discuss findings from dual-task studies of normal and aphasic performance. First, competing language and nonlanguage tasks appear to share limited-capacity, parallel processing resources. Second, aphasic individuals demonstrate slowed central processing that could be due to a reduction in processing capacity or ability to allocate that capacity. Third, the attention models discussed bear a coherent relationship to current models of language processing. Clinical implications of a cognitive processing account of aphasia are also considered. <s> BIB048 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> R. Martin and colleagues have proposed separate stores for the maintenance of phonological and semantic information in short-term memory. Evidence from patients with aphasia has shown that damage to these separable buffers has specific consequences for language comprehension and production, suggesting an interdependence between language and memory systems. This article discusses recent research on aphasic patients with limited-capacity short-term memories (STMs) and reviews evidence suggesting that deficits in retaining semantic information in STM may be caused by a disorder in the executive control process of inhibition, specific to verbal representations. In contrast, a phonological STM deficit may be due to overly rapid decay. In semantic STM deficits, it is hypothesized that the inhibitory deficit produces difficulty inhibiting irrelevant verbal representations, which may lead to excessive interference. In turn, the excessive interference associated with semantic STM deficits has implications for single-word and sentence processing, and it may be the source of the reduced STM capacity shown by these patients. <s> BIB049 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> a b s t r a c t The characteristic organization of cortex, basal ganglia and thalamus can be considered a ‘‘canonical’’ macro-circuit of the primate brain. The intact function of the system requires intact function at the different nodes of the circuit. Cortico-striatal circuits are compromised in Parkinson’s disease (PD) due to progressive loss of dopamine-producing neurons in the basal ganglia. Among the cognitive deficits observed in PD is an ensemble of perturbations in language processing, thus implying a role for basal ganglia in language. Related studies have suggested that basal ganglia dysfunction results in a more general deficit in certain forms of rule-based processing. From a functional neurophysiology perspective, neuro-imaging studies reveal activation of the striatum in diverse aspects of language processing including syntactic comprehension. We present a model in which the unique capacity for the striatum to integrate functionally related cortical inputs is exploited for language processing. Converging corticostriatal connections provide a mechanism that binds cortical representations of syntactic context in BA47 to structure mapping representations (corresponding to grammatical constructions) in BA44. This allows the retrieval of the appropriate grammatical construction to BA44 via thalamo-cortical connections, where it is subsequently used to perform the structure mapping. In this model, the rule retrieval function of the corticostriatal systems is not unique to language. The model is evaluated in the context of behavioral and neurophysiological results from basal ganglia dysfunction. Likewise, as the model makes strong assumptions about the cortical and subcortical neuroanatomy, recent results in human neuroanatomy are reviewed in the context of these assumptions. <s> BIB050 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Abstract Parkinson's disease (PD) is characterised by a slowly expanding degeneration of neurons particularly in the mesencephalon. The causes are unknown although risk factors in the genetic and toxic domain are being discovered. An important pathophysiological feature in PD is the loss of part of the dopaminergic neurons in the substantia nigra (SN) resulting in a specific dysorganisation of the complicated basal ganglia (BG) circuits. The relay functions at the level of the striatum e.g., are out of balance leading to disturbed subcortico-cortical interactions. At a functional level this is shown by timing and scaling problems when performing movements and clinically this translates into initiation problems, bradykinesia and others. Dysarthria can of course be an important problem. However, how these basic disturbances of motor organisation can be copied into the cognitive domain (in terms of disturbed “mental movements”) is a topic under discussion. It remains to be seen whether the basic pathophysiology of PD has consequences for the specific language organisation by the brain or whether language problems are merely secondary to the overall “mental motor slowing”. Here an overview of the pathogenesis, basic pathophysiology and clinical problems of PD will be given. <s> BIB051 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Past research indicates that in Parkinson's disease (PD), set-shifting deficits cause impaired comprehension of sentences containing restrictive relative clauses (RCs). Some research also suggests that verbal working memory deficits impair comprehension of long-distance (LD) dependencies in sentences with center-embedded RCs. To test whether these deficits impair comprehension by affecting on-line processing, we tracked patients' eye movements as they matched pictures with sentences with final- or center-embedded RCs (e.g., The queen was kicking the cook who was fat, The queen who was kicking the cook was thin) and active or passive verbs. Decreases in looks to distracters ruled out at the transitive verb (e.g., a cook kicking a queen) and the adjective (a fat queen kicking a thin cook) reflected how effective processing was at those points. Though patients showed greater difficulty comprehending center-embedded and passive sentences, set-shifting errors correlated with comprehension of all sentences. Consistent with this, patients with poorer comprehension exhibited impaired on-line processing of both center-embedded and final RCs (for which comprehension was better due to their grammatical simplicity), and these effects correlated with set-shifting errors. We consider two possible explanations for this apparently general RC-processing deficit. First, because RCs are infrequent, set-shifting may be needed to override the processor's expectations for higher-frequency structures. Second, because restrictive RCs typically refer to information already in the discourse context, set-shifting may be needed to redirect attention from linguistic foreground to background information. Eye-tracking data indicated no difficulty processing LD dependencies; correlations of verbal working memory with comprehension of passive and center-embedded sentences may reflect off-line use of memory. In trials with passive verbs, patients looked toward the verb distracter before even processing the verb. This effect was larger than that previously seen for young participants, suggesting that PD may amplify a normal bias to assume the subject noun is the agent. <s> BIB052 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> This study investigated the effects of syntactic complexity on written sentence comprehension in compensated adults with dyslexia. Because working memory (WM) plays a key role in processing complex sentences, and individuals with dyslexia often demonstrate persistent deficits in WM, we hypothesized that individuals with dyslexia would perform more poorly on tasks designed to assess the comprehension of syntactic structures that are especially taxing on WM (e.g., passives, sentences with relative clauses). Compared to their nondyslexic peers, individuals with dyslexia were significantly less accurate and marginally slower on passive sentences. For sentences containing relative clauses, the dyslexic group was also less accurate but did not differ in response times. Covarying WM and word reading in both analyses eliminated group differences showing that syntactic deficits in adults with dyslexia are constrained by both WM and word-reading ability. These findings support previous research showing that syntactic processing deficits are characteristic of dyslexia, even among high-achieving students. <s> BIB053 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Nine early non-demented bilingual (L1 – Friulian, L2 – Italian) patients with Parkinson’s disease and nine normal controls matched for age, sex and years of education were studied on a spontaneous language production task. All subjects had acquired L1 from birth in a home environment and L2 at the age of six at school formally. Patients with PD evidenced more phonological, morphological and syntactic errors in L1 than in L2. The opposite pattern was observed in normal controls as far as grammar was concerned. These findings suggest that implicit language processing is more impaired than explicit language processing in Parkinson’s disease. <s> BIB054 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Participants indicated with a finger press whether a visual stimulus was colored pink or blue. The stimulus was either the written word "BLUE," the written word "PINK," or a string of four Xs, with word interference introduced when the meaning of the word and its color were "incongruent" (e.g., BLUE in pink hue) relative to congruent (e.g., BLUE in blue) or neutral (e.g., XXXX in pink). The participants also made color decisions in the presence of spatial interference rather than word interference (i.e., the Simon task). By blocking incongruent, congruent, and neutral trials, we identified activation related to the mechanisms that suppress interference as that which was greater at the end relative to the start of incongruency. This highlighted the role of the left head of caudate in the control of word interference but not spatial interference. The response in the left head of caudate contrasted to bilateral inferior frontal activation that was greater at the start than at the end of incongruency, and to the dorsal anterior cingulate gyrus which responded to a change in the motor response. Our study therefore provides novel insights into the role of the left head of caudate in the mechanisms that suppress word interference. <s> BIB055 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Introduction <s> Experimental studies of sentence production in Parkinson disease (PD) are rare. This study examined the relationship between cognitive abilities and performance on two sentence production tasks, sentence repetition, and sentence generation, in which complexity was manipulated. Thirty-eight older adults aged 60 to 85, half with PD, completed the two language tasks plus a cognitive battery. Participants with PD performed more poorly in the repetition task overall, especially in fluency, but differences were no longer significant once cognitive ability was controlled. In contrast, on the sentence generation task the PD group was significantly impaired on all language dimensions and overall performance. Although cognitive ability accounted for significant variance in all measures of sentence generation, the PD group remained significantly impaired when these factors were controlled. These findings suggest that, although language production is influenced by cognitive abilities, it can be significantly impaired in PD over and above the effects of differences in cognitive abilities. <s> BIB056
The current paper focuses on high-level, complex language production in Parkinson's disease (PD), in which "high-level, complex language" is defined as production of language at the sentence-or discourse-level in contrast to single-word production. In comparison to the extensive literature on motor impairments affecting articulation and intelligibility of speech (e.g., BIB028 BIB016   BIB001 BIB002 ) and neuropsychological reports of impaired picture naming and verbal fluency in PD  BIB007 BIB005 BIB012 BIB017 BIB004  , the literature on complex language production is somewhat limited. However, those few reports converge on a few common themes. First, while information content has been assessed in a variety of ways, including clinical judgment BIB010 , correct information units BIB024 , propositional content BIB021 , or specific mention of the actors in a picture and an appropriate action BIB056 , the findings uniformly support reduced information content. Second, although examined in only a few studies, fluency seems to be impaired BIB056 BIB013 BIB011 . Interruptions of fluency take many forms, including abandoned utterances, long pauses between or in the middle of sentences, or filled and unfilled pauses. The studies agree that disruptions of fluency can be attributed to difficulties in the early stages of language production (e.g., conceptualization and formulation) as well as problems during motor programming and articulation BIB056 BIB013 BIB011 . Third, grammaticality has also been reported to be impaired BIB024 BIB021 BIB056 BIB054 . Finally, syntactic complexity may also be impaired although this may be limited to individuals with moderately severe PD or to performance in more difficult language tasks BIB024 BIB021 BIB013 BIB011 BIB029 . Within this body of literature, there has been a strong tradition of correlating changes in language production with cognitive abilities BIB024 BIB056 BIB054 BIB034 . Recent studies have gone beyond this descriptive approach by seeking to define those subject and stimulus variables that exacerbate production difficulties in PD, examining the effects of complexity (syntactic and conceptual) on language production deficits BIB056  . In this paper, we first briefly discuss the effects of PD on the brain and cognition and then present a review of the literature ending with discussions of our own recent experimental study that has broken new ground in this area. Finally, working within the most commonly cited theoretical model of language production, we explore which stages of language production might be impaired in PD as well as which of these stages of the production process seem to be vulnerable to differences in cognitive ability. Finally, we present ideas for future research inspired by the preceding discussion. Based on models which proposed that subcortical structures, specifically the basal ganglia and thalamus, were instrumental in language processing, several researchers predicted language impairments in PD before these were well documented BIB009 BIB022  . More specifically, Crosson BIB006 suggested that basal ganglia damage could result in deficits of both motor programming and language formulation through their connections with the cortex. In particular, thalamic, putamen, and caudate function are impaired early in the progression of PD BIB039 , and these structures are hypothesized to integrate or control attention to input from the superior and middle temporal gyri, (BA 41, BIB048 BIB029 BIB034 and dorsolateral prefrontal cortex (dlPFC), especially BA 44,  , and 47, during language processing BIB022 BIB050 . Therefore, disruption of these large cortico-striato-pallidothalamocortical circuits could impair aspects of language production BIB025 BIB035 BIB018 . Furthermore, several imaging studies have demonstrated that frontostriatal circuits are also active during executive function tasks that require set switching BIB040 and inhibition of prepotent responses BIB055 , suggesting that damage to these circuits could impact both language and cognitive functions. Moreover, delayed transmission of information through these networks due to loss of connections resulting from PD related lesions BIB026 BIB051 could also interfere with the smooth flow of information between language areas. This could lead to impaired fluency of speech, if the language system has to wait for the next sentence elements to become available, or impaired computation of grammaticality if information necessary for computing agreement, for example, is no longer (or not yet) available when a verb is active BIB019 . Additionally, impairments affecting the continuous interaction between language areas could diminish information content in language output if the dynamics of conversational speech require a response to be started before specific conceptual information has been fully activated and made available to the language production system. In addition to subcortical structures, PD also impairs function of dlPFC, which also plays an instrumental role in many aspects of language use BIB050 BIB036 and in the cognitive abilities that support language such as working memory and executive function BIB010 BIB055 BIB030 BIB043 BIB052 BIB048 BIB049 BIB041 . Thus, research supports the assertion that both cortical and subcortical structures contribute to cognitive processing and language use. Cognitive impairments are common in PD with nearly 80 percent of persons with PD developing cognitive impairment BIB004 BIB010  BIB044 . In fact, Muslimović et al. BIB044 reported that 100% of the 115 participants in their study were significantly impaired on at least one cognitive task. Deficits in cognition secondary to PD impact many domains, including memory, visuospatial function, and concept formation, with executive function and working memory (WM) being the first affected (e.g., BIB014 BIB003 BIB008 BIB015 BIB042 ). Executive function impairments are most commonly reported to affect anticipation, planning, initiation, inhibitory processing, and set and task switching BIB044 BIB047 BIB031 BIB045 BIB027 BIB032 . Dual task performance, which is also considered to involve executive function BIB037 , is also impaired in PD BIB020 BIB046 . As previously mentioned, working memory is impaired, especially when tasks require manipulation rather than storage or updating of information BIB027 BIB032 . As pointed out by Lewis et al. BIB023 , language production may rely on many of these same cognitive abilities, such as initiation, planning, and inhibitory processing as well as concept formation and the manipulation of information, leaving language production vulnerable in PD. Based on this reasoning, it has become relatively common for researchers to compare cognitive abilities and language performance in studies of PD BIB024 BIB056 BIB054 BIB034  BIB023 BIB038 BIB033 . Most recently, Bastiaanse and Leenders  commented that there was little doubt that the cognitive deficits in PD were fully responsible for the language impairments found in this population, and, therefore, there were no specific linguistic deficits secondary to this disease. However, our own research, described below, suggests that while working memory and executive function account for significant, substantial proportions of variance in many characteristics of language production in PD and healthy older adults, there are group differences in performance in many dimensions of language production that cannot be accounted for by performance on standard measures of cognitive abilities alone BIB056 . Our findings need not be considered to support a modular view of language and cognition; indeed, we find strong evidence that working memory, executive function, and speed of processing play critical roles in language production and comprehension BIB056 BIB053  . However, while many cognitive and linguistic functions may share underlying neural mechanisms and task demands, there may also be neural circuits that are primarily used in language production that are independently damaged in PD.