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Background: Mild cognitive impairment (MCI) in Parkinson’s disease (PD) is considered a risk factor for PD with dementia (PDD). Verbal fluency tasks are widely used to assess executive function in PDD. However, in cases of PD with MCI (PD-MCI), the relative diagnostic accuracy of different qualitative verbal fluency measures and their related neural mechanisms remain unknown. Objective: This study aimed to investigate the relative diagnostic accuracy of qualitative (clustering and switching) verbal fluency strategies and their correlates with functional imaging in PD-MCI. Methods: Forty-five patients with PD (26 with MCI and 19 without MCI) and 25 healthy controls underwent comprehensive neurocognitive testing and resting-state functional magnetic resonance imaging. MCI in patients with PD was diagnosed according to established clinical criteria. The diagnostic accuracy of verbal fluency measures was determined via receiver operating characteristic analysis. Changes in brain functional connectivity between groups and across clinical measures were assessed using seed-to-voxel analyses. Results: Patients with PD-MCI generated fewer words and switched less frequently in semantic and phonemic fluency tasks compared to other groups. Switching in semantic fluency showed high diagnostic accuracy for PD-MCI and was associated with reduced functional connectivity in the salience network. Conclusion: Our results indicate that reduced switching in semantic fluency tasks is a sensitive and specific marker for PD-MCI. Qualitative verbal fluency deficits and salience network dysfunction represent early clinical changes observed in PD-MCI.

Abstract:We developed a qualitative analysis method for verbal fluency tasks in Japanese natives. In this paper, we discuss the validity and characteristics of our qualitative analysis. The purpose of study 1 was to detect and visualize clusters seen during animal category verbal fluency. We used cluster analysis with collocation ratios between animal names seen in verbal fluency tasks as parameters. The purpose of study 2 was to verify the consistency between clusters seen during animal category verbal fluency and semantic similarity. We carried out a semantic similarity decision task of animal names and analyzed the scores with cluster analysis techniques. We compared the results with the results obtained in study 1. The purpose of study 3 was to examine the characteristics of our qualitative analysis method. We used principal component analysis on the collocation ratios obtained in study 1 and semantic similarity scores obtained in study 2 and compared the results. The results of 臨床福祉専門学校言語聴覚療法学科 1）