Short and valid assessment of apraxia in Parkinson's disease.

Background: Valid assessment of apraxia in usually non-apraxic Parkinson's disease helps to delineate atypical parkinsonism frequently associated with apraxia. Furthermore, in a subgroup of late Parkinson's disease apraxia, typically the ideomotor subtype, may gradually superimpose onto parkinsonian motor symptoms contributing to defective manual skill. Here we evaluate the utility of a brief, standardized test, the apraxia screen of TULIA (AST).
Methods: Seventy five Parkinson's disease patients were tested with the AST. Parkinsonian motor deficits were measured using Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III and difficulties in activities of daily living (ADL) by modified MDS-UPDRS part II (eating, dressing, personal hygiene, and writing).
Results: No association was found between the AST and MDS-UPDRS part III, indicating that AST discriminates well (discriminative validity) between apraxia and parkinsonism. Furthermore, AST was associated with ADL and Hoehn & Yahr stage (convergent validity).
Conclusions: AST is a short and valid test to rule out or detect apraxia in Parkinson's disease.
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