High-Level Language Production in Parkinson's Disease: A Review <s> Positional Level Processing. <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> Positional Level Processing. <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> Positional Level Processing. <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> Positional Level Processing. <s> Language comprises a lexicon for storing words and a grammar for generating rule-governed forms. Evidence is presented that the lexicon is part of a temporal-parietalhnedial-temporal “declarative memory” system and that granlmatical rules are processed by a frontamasal-ganglia “procedural” system. Patients produced past tenses of regular and novel verbs (looked and plagged), which require an -ed-suffixation rule, and irregular verbs (dug), which are retrieved from memory. Word-finding difficulties in posterior aphasia, and the general declarative memory impairment in Alzheimer's disease, led to more errors with irregular than regular and novel verbs. Grammatical difficulties in anterior aphasia, and the general impairment of procedures in Parkinson's disease, led to the opposite pattern. In contrast to the Parkinson's patients, who showed sup pressed motor activity and rule use, Huntington's disease patients showed excess motor activity and rule use, underscoring a role for the basal ganglia in grammatical processing. <s> BIB004 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Positional Level Processing. <s> Preparing words in speech production is normally a fast and accurate process. We generate them two or three per second in fluent conversation; and overtly naming a clear picture of an object can easily be initiated within 600 msec after picture onset. The underlying process, however, is exceedingly complex. The theory reviewed in this target article analyzes this process as staged and feedforward. After a first stage of conceptual preparation, word generation proceeds through lexical selection, morphological and phonological encoding, phonetic encoding, and articulation itself. In addition, the speaker exerts some degree of output control, by monitoring of self-produced internal and overt speech. The core of the theory, ranging from lexical selection to the initiation of phonetic encoding, is captured in a computational model, called weaver ++. Both the theory and the computational model have been developed in interaction with reaction time experiments, particularly in picture naming or related word production paradigms, with the aim of accounting for the real-time processing in normal word production. A comprehensive review of theory, model, and experiments is presented. The model can handle some of the main observations in the domain of speech errors (the major empirical domain for most other theories of lexical access), and the theory opens new ways of approaching the cerebral organization of speech production by way of high-temporal-resolution imaging. <s> BIB005 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Positional Level Processing. <s> The present study investigates the production of regular and irregular verbs in the past tense and the comprehension of passive sentences by Greek-speaking PD patients, and compares their behavior to that of normal speakers. Although the two groups manifest large scale differences at all the above constructions, the behavior of PDs is not different at regular vs. irregular past tense formation neither did we obtain strong evidence that they do not comprehend passives, most importantly, they certainly do not perform at chance. On the basis of the above, we conclude that there are no indications for a clearly linguistic deficit of the PD group, hence, their difference with the control group should be attributed to other factors, such as the computational demands of the tasks. <s> BIB006 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Positional Level Processing. <s> The Declarative/Procedural Model of Pinker, Ullman and colleagues claims that the basal ganglia are part of a fronto-striatal procedural memory system which applies grammatical rules to combine morphemes (the smallest meaningful units in language) into complex words (e.g. talk-ed, talk-ing). We tested this claim by investigating whether striatal damage or loss of its dopaminergic innervation is reliably associated with selective regular past tense deficits in patients with subcortical cerebrovascular damage, Parkinson's disease or Huntington's disease. We focused on past tense morphology since this allows us to contrast the regular past tense (jump-jumped), which is rule-based, with the irregular past tense (sleep-slept), which is not. We used elicitation and priming tasks to test patients' ability to comprehend and produce inflected forms. We found no evidence of a consistent association between striatal dysfunction and selective impairment of regular past tense morphology, suggesting that the basal ganglia are not essential for processing the regular past tense as a sequence of morphemes, either in comprehension or production, in contrast to the claims of the Declarative/Procedural Model. All patient groups showed normal activation of semantic and morphological representations in comprehension, despite difficulties suppressing semantically appropriate alternatives when trying to inflect novel verbs. This is consistent with previous reports that striatal dysfunction spares automatic activation of linguistic information, but disrupts later language processes that require inhibition of competing alternatives. <s> BIB007
From the functional level of processing, information flows to the positional processing level during which the phonological forms of words are activated and the linear structure of the sentence is generated   BIB003 . Tasks requiring sentence repetition may begin the language process about here, since no message generation or grammatical formulation is required. Notably, in our study described above, only fluency was impaired in the repetition task in PD, regardless of grammatical complexity. Fluency is discussed below in Section 3.4. Other deficits that might be attributed to dysfunction at the positional level of processing would be increased tip-of-the-tongue phenomena, phonemic paraphasias, aberrant word order, and some types of grammatical errors. While word finding difficulties have been reported in PD BIB001 , no experimental investigations of TOT phenomena in PD have been reported to our knowledge. Phonemic paraphasias would be difficult to distinguish in PD due to the prevalence of hypokinetic dysarthria. To our knowledge, there have been no reports of the production of sentences with aberrant word order in PD. Positional level grammatical processing is associated with accessing phonetic forms of inflectional morphology and closed class words    . As mentioned above, Ullman and colleagues BIB004 have reported morphological difficulties affecting the production of regular past tense verbs in PD, which would implicate difficulties at the positional level of processing. However, several studies have failed to replicate this effect  BIB006 BIB007 . Further, while several studies detailed above have reported grammatical errors, none of the current studies on PD have distinguished between functional level and positional level grammatical errors; therefore, the etiology of grammatical errors in PD is unknown. Thus, there is little evidence that the grammatical errors in PD originate in dysfunction at the positional processing level although there may be fluency impairments at this level, as discussed below. We suspect the grammatical errors in PD occur before positional level processing during functional level, grammatical formulation, or the transfer of information from functional to positional level processing, because they occur in generation but not repetition tasks. BIB003 BIB005 also include a monitor in their model of language production that checks planned language output (after or during positional processing) against the conceptual representation of the intended utterance. Levelt et al. BIB005 argue that monitoring focuses on either the phonetic or phonological level, as well as on overt speech, but it is unknown whether the monitor is equally adept at detecting all types of errors (e.g., semantic and phonemic paraphasias and grammatical errors). The typical effects of the monitor would be false starts, in which the speaker halts mid-sentence and begins again with a sentence plan that may or may not be completely different from originally intended utterance. Of the studies discussed, only Illes BIB002 specifically assessed self-corrections and found that individuals with PD produced about the same number of self-corrections as control subjects. However, the author does not report the proportion of potential corrections for each group, so it is unknown whether this self-correction rate represents preserved or impaired monitoring. However, reviewing the studies above, the prevalence of uncorrected grammatical errors suggests that monitoring of this type of error may be impaired in PD. On the other hand, few (if any) studies of grammatical error monitoring have been reported, so it is unknown how frequently healthy speakers detect and correct grammatical errors. Therefore, whether self-monitoring of language production is impaired in PD is an open question.