COMPARING THE DIFFICULTY OF LETTER, SEMANTIC, AND NAME FLUENCY TASKS FOR NORMAL ELDERLY AND PATIENTS WITH PARKINSONS-DISEASE

Research on the effect of Parkinson's disease (PD) on verbal fluency h as produced conflicting results. In this study, 88 PD patients with no dementia, 11 PD patients with questionable mental status, 15 PD patie nts with dementia, and 46 elders free from mental disorder were admini stered a variety of semantic, letter, and name fluency tasks. The resu lts revealed that, contrary to popular assumption, semantic fluency wa s not always superior to letter fluency. Rather, verbal fluency was in fluenced by the nature of the individual categories. Interestingly, th e relative difficulty of many categories was fairly stable across grou ps. The results also indicated that the individual fluency tasks were differentially sensitive to the mental status of the PD patients. Over all, the findings su sst that closer attention to the nature of the te sted categories may help clarify the inconsistent effects of PD on ver bal fluency.