High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB001 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB002 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <s> In Speaking, Willem "Pim" Levelt, Director of the Max-Planck-Institut fur Psycholinguistik, accomplishes the formidable task of covering the entire process of speech production, from constraints on conversational appropriateness to articulation and self-monitoring of speech. Speaking is unique in its balanced coverage of all major aspects of the production of speech, in the completeness of its treatment of the entire speech process, and in its strategy of exemplifying rather than formalizing theoretical issues. <s> BIB003 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <s> Speech samples were obtained that were analyzed for voice onset time (VOT) for 40 nondemented English speaking subjects, 20 with mild and 20 with moderate Parkinson's disease. Syntax comprehension and cognitive tests were administered to these subjects in the same test sessions. VOT disruptions for stop consonants in syllable initial position, similar to those noted for Broca's aphasia, occurred for nine subjects. Longer response times and errors in the comprehension of syntax as measured by the Rhode Island Test of Sentence Comprehension (RITLS) also occurred for these subjects. Anovas indicate that the VOT overlap subjects had significantly higher syntax error rates and longer response times on the RITLS than the VOT nonoverlap subjects—F(1, 70) = 12.38, p < 0.0008; F(1, 70) = 7.70, p < 0.007, respectively. The correlation between the number of VOT timing errors and the number of syntax errors was significant. (r = 0.6473, p < 0.01). VOT overlap subjects also had significantly higher error rates in cognitive tasks involving abstraction and the ability to maintain a mental set. Prefrontal cortex, acting through subcortical basal ganglia pathways, is a component of the neural substrate that regulates human speech production, syntactic ability, and certain aspects of cognition. The deterioration of these subcortical pathways may explain similar phenomena in Broca's aphasi. Results are discussed in relation to “modular” theories. <s> BIB004 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <s> Methodological problems have been a longstanding barrier to the systematic exploration of issues in language production. Recently, however, production research has broadened beyond traditional observational approaches to include a diverse set of experimental paradigms. This review surveys the observational and experimental methods that are used to study production, the questions to which the methods have been directed, and the theoretical assumptions that the methods embody. Although tailored to the investigation of language production, most of the methods are closely related to others that are widely employed in cognitive research. The common denominator of these procedures is verbal responding. Because the processing complexities of verbal responses are sometimes overlooked in research on memory, perception, attention, and language comprehension, the methodological assumptions of production research have implications for other experimental procedures that are used to elicit spoken words or sentences. <s> BIB005 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB006 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB007 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <s> Abstract Sentence processing in Alzheimer's disease (AD) has been found to be influenced by several grammatical and extragrammatical factors, including phrase structure and verb–argument relations, number of propositions/verbs, and processing resource capacity. This study examines the effects of these variables on sentence production in AD. Normal control and AD subjects were asked to repeat six types of sentences varying along the above dimensions of complexity. Subjects' processing resource capacity was measured using several verbal working memory tests. AD subjects' sentence-repetition performance was impaired compared to the normal control group. Significant effects were observed for branching direction of phrase struc- ture, canonicity of verb–argument relations, and serial position of errors. Sentence-repetition performance significantly correlated with working memory scores. The findings are interpreted within a resource capacity theory of sentence processing. <s> BIB008 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB009 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <s> Narratives were elicited in two story tasks, retelling and generation, from two groups of adults, 55 with closed head injury (CHI) and 47 non-brain-injured (NBI), recruited from rehabilitation facilities in three northeastern states. Participants were classified, on the basis of their socioeconomic status (SES), as professional, skilled worker, or unskilled worker. Narratives were analyzed using five discourse measures at the levels of sentence production, intersentential cohesion, and story grammar. Discourse performance was then compared across groups, tasks, and SES levels. Discourse performance of the CHI group was also compared with their scores from the Wisconsin Card Sorting Test, a measure of executive functioning. Results indicated that two discourse measures distinguished the groups. The CHI participants produced significantly fewer words per T-unit and fewer T-units within episode structure than did the NBI group, which was attributed to difficulties with content organization. Performance on al... <s> BIB010 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB011 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB012 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB013 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Producing Language <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> BIB014
As shown above, from the very early years, researchers of language production in PD have focused on examining performance on a variety of dependent variables, often looking at both single-word and sentence or discourse production as well as comprehension BIB011 BIB006 BIB004 . Moreover, many of these studies have included cognitive covariates years before this became popular in the mainstream psycholinguistic literature (e.g., BIB007 BIB011 BIB006 BIB004 ). Indeed, it is still unusual to find studies looking at the impact of executive function on language production in healthy young adults unless they are contrasted with other populations BIB012    BIB010 . In the following section, we describe the most commonly cited model of language production, one stage at a time, and speculate about the types of errors we believe would result from dysfunction at each level. We also discuss whether these types of errors are found in PD and whether they are associated with individual differences in cognitive ability. Our goals are to determine which stages of the language production process are affected in PD and, to the extent we can from the limited studies available, which stages are vulnerable to cognitive limitations. While earlier studies compared performance to dementia severity or divided groups by dementia severity BIB001 BIB002 BIB011 BIB006 BIB008 , more recent studies have begun to use a larger variety of tasks measuring both working memory BIB007 BIB014 BIB009 and executive function BIB014 BIB013  . The consistent finding has been that, as cognition becomes more impaired, difficulties in language production increase. The dominant model of sentence production today was first suggested by Garrett    , and later refined by Levelt and Bock BIB005  BIB003 . This model specifies five stages in the sentence generation process: the message level, functional processing, positional processing, motor programming, and articulation. The current paper has been primarily concerned with processing at the first three levels.