Background: Patients suffering from Parkinson's disease (PD) are often reported to have an impaired performance on tests measuring executive functioning, such as fluency tasks. Aim: To investigate whether verbal fluency is impaired in PD patients (n = 25) compared with healthy controls (n = 15) using a 2-min semantic and phonemic verbal fluency test. A 2-min version of the fluency task was used to allow for more switches between clusters to study retrieval strategies more adequately. Results: No differences in performance on both semantic and phonemic fluency tasks between the PD patients and the control persons were found. Moreover, both groups appeared to use the same retrieval strategies. Conclusion: Patients suffering from PD appear to use the same strategies for producing words as healthy controls do. Different pathways may be involved in switching clusters during the fluency task than in other types of switching that may be impaired in PD, such as motor switching and concept-shifting.
Scholtissen, B., Reithler, J., Dijkstra, J., & Leentjens, A. F. G. (2006). Verbal fluency in Parkinson's disease: results of a two minute fluency test. Acta Neuropsychiatrica, 18, 38-41. https://doi.org/10.1111/j.0924-2708.2006.00122.x