[Word fluency for "Ka" in Parkinson's disease patients: comparison with memory clinic patients]

Domestic studies examining word fluency tasks in patients with Parkinson's disease (PD) are limited. This study compared quantitative and qualitative features of a word fluency task included in the Japanese version of the Montreal Cognitive Assessment (MoCA-J) between patients with PD and patients attending a memory clinic. We retrospectively analyzed the MoCA-J word fluency task requiring the generation of words beginning with the Japanese syllable "ka" in 100 patients with PD and 100 memory clinic patients. The number of recalled words and linguistic characteristics of the responses were evaluated. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and MoCA-J. The mean MMSE scores were higher in the PD group than in the memory clinic group (27.6 vs. 24.4), as were MoCA-J scores (23.5 vs. 18.7). The mean number of recalled words did not differ between groups (PD: 9.1; memory clinic: 9.2) and showed positive correlations with cognitive scores. The PD group produced 318 unique words, whereas the memory clinic group produced 285. The proportion of adjectives was lower in the PD group. No significant between-group differences were observed in semantic category classifications, including object names, motion-related words, and emotion/state-related words. Although global cognitive function was relatively preserved in patients with PD, their word fluency performance was comparable to that of memory clinic patients, with subtle differences in linguistic characteristics.