Cognitive or Cognitive-Motor Executive Function Tasks? Evaluating Verbal Fluency Measures in People with Parkinson's Disease

INTRODUCTION: Executive function deficits are observed in people with Parkinson's disease (PD) from early stages and have great impact on daily living activities. Verbal fluency and oral diadochokinesia involve phonarticulatory coordination, response inhibition, and phonological processing and may also be affected in people with PD. This study aimed to describe the performance of PD patients and an age- and education-matched control group on executive function, verbal fluency, and oral diadochokinesia tests and to investigate possible relationships between them. METHODS: Forty people with PD and forty controls were evaluated with Trail Making Test (TMT, executive function) and phonemic/semantic verbal fluency and oral diadochokinesia (/pataka/) tests. Groups were compared by ANOVA and relationships were investigated by Pearson tests. RESULTS: People with PD showed longer times in parts A and B of TMT. They also said fewer words in phonemic/semantic verbal fluency tests and less syllables in the diadochokinesia test. Oral diadochokinesia strongly correlated to parts A and B of TMT and to phonemic verbal fluency. CONCLUSION: Oral diadochokinesia was correlated to executive function and verbal fluency. The cognitive-motor interaction in verbal fluency and oral diadochokinesia must be considered not to overestimate the cognitive or motor impairments in people with PD.