High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> Future Directions and Conclusion <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> BIB002 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB003 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB004 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB005 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB006 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB007 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB008 </s> High-Level Language Production in Parkinson's Disease: A Review <s> Future Directions and Conclusion <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> BIB009
Future studies examining PD language within a specific model of language production that includes hypotheses about cognitive contributions to each stage of processing will advance our understanding of the effects of PD on language production and communication as well as further the overall understanding of the relationship between language production and cognitive processing. As shown here, while the literature is not extensive, language production in PD has been well described; therefore, future studies on language production in PD should continue to embrace hypothesisdriven experimental methods (e.g., BIB009 BIB008 BIB007  ). This will allow a more precise delineation of the language impairments in PD that can then be developed into therapeutic strategies to circumvent these impairments. Several topics suggest themselves for further research. First, it is highly likely that grammatical errors and fluency disruptions are not unitary constructs. Specific tasks could be designed, for example, that specifically target grammatical errors at the functional level versus the positional level of 9 language production. These studies should include a cognitive battery to determine whether each type of grammatical error is subject to the same cognitive constraints. Another important opportunity for research would be to explore the relationship between deficits in verb access in PD, cognitive abilities, and the various language impairments documented here (i.e., reduced information content, impaired grammaticality, reduced syntactic complexity, and reduced fluency). These types of studies would be theoretically enlightening, while also identifying potential therapeutic targets for intervention. Similarly, analyses that examine different types of disfluencies might clarify which aspects of the language production process are most responsible for the fluency difficulties in PD. For example, fluency difficulties due to formulation difficulties (i.e., abandoned utterances and false starts) are relatively easily distinguished from those that signify synchronization difficulties (sentence-medial pauses, restarts, and filled pauses) but not so easily distinguished from the effects of self-monitoring. A testable hypothesis is that these two types of fluency difficulty will align differently with cognitive measures; specifically, synchronization disfluencies may correlate with timing measures, while formulation and monitoring disfluencies may relate to executive function abilities. A study testing this hypothesis is currently underway in our lab. Another potential avenue of research could explore the effects of the decrease in information content and conceptual complexity on the adequacy of language output from the listener's point of view. Particular types of discourse could be contrasted in these studies, such as giving directions and procedural discourse (e.g., telling someone how change a flat tire) in which sufficiency of information would be a critical element for the listener. This issue should be explored using real-world communication scenarios involving complex topics to determine the extent to which crucial information is omitted during the discourse. This type of study is needed to determine if, for example, the decrease in information content in PD discourse might have functional consequences. Along similar lines, to our knowledge, there is no research on the relationship between language impairments in PD, especially impaired information content and fluency, and the dynamics of the 3-way conversation between the individual with PD, the spouse, and an authority figure. Anecdotally, it is not uncommon in PD for the caregiver to increasingly take over as the "voice" of the patient with PD so that their chances of participating in discussions about complex topics may diminish over time. It is possible that this change is directly related to the language production difficulties in PD such as reduced information content and impaired fluency. This type of study could lead to important insights into doctor-patient communication that could fundamentally change the communication dynamic in the examination room. This research could lead to family interventions to maximize the opportunities of the individual with PD to express their own thoughts and opinions. A related and completely unstudied avenue of research is the relationship between language production deficits, instrumental activities of daily living, and quality of life in PD. For example, there may be a direct relationship between a person's ability to communicate clearly and their ability to make appointments, take down telephone messages, communicate concerns to their physician, or discuss financial and legal issues. In summary, language production in PD has been well described with studies converging on several themes. There is general agreement that information content is reduced in PD across various language tasks, including conversational discourse, picture description tasks, and written sentences BIB001 BIB005 BIB004 BIB009 . These deficits likely represent limitations in activation at the message level of sentence production and in sentence formulation BIB003 BIB002 . Grammaticality of oral language production also appears to be vulnerable to impairment in PD, particularly in more difficult tasks BIB005 BIB009 BIB008  . Findings regarding the simplification of syntax have been mixed but suggest that in more difficult, constrained tasks such as picture description and syntax may be simplified BIB001 BIB005 , while in easier tasks like spontaneous conversation, syntactic complexity may be unimpaired BIB003 BIB002 BIB006 . Fluency is a common problem in PD language production BIB009 BIB003 BIB002 and should be investigated as a language impairment as well as motor speech impairment. An additional common theme throughout the complex language production studies reviewed above has been the contribution of cognitive ability to language performance. All of the impaired aspects of language production in PD have now been shown to be vulnerable to cognitive impairment BIB004 BIB009 BIB002 BIB008  . In addition, newly popular statistical procedures such as hierarchical linear modeling and multivariate regression offer a means to simultaneously determine the effects of group, cognitive covariates, experimental conditions, and their potential interactions. Continuing research on language production in PD is needed to provide practitioners with evidence-based targets for intervention.