[Word fluency in spinocerebellar degeneration]

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• Verbal fluency tasks assess executive functions and semantic memory.
• Spinocerebellar degeneration (SCD) and Parkinson disease (PD) are neurodegenerative disorders affecting motor and cognitive functions.
• Understanding the specific cognitive deficits in these conditions is crucial for diagnosis and management.

Purpose of the Study:

• To investigate verbal fluency performance in patients with SCD and PD compared to controls.
• To differentiate the impact of initial letter fluency and category fluency on these patient groups.
• To explore the underlying neural mechanisms contributing to observed fluency deficits.

Main Methods:

• Eleven patients with SCD, twenty-four with PD, and twenty healthy controls participated.
• Participants underwent initial letter fluency and category fluency tasks.
• Dementia screening confirmed no cognitive impairment in participants.

Main Results:

• Category fluency was significantly lower in both SCD and PD patients compared to controls.
• Initial letter fluency was significantly lower in SCD patients but not in PD patients compared to controls.
• Performance on both tasks was generally lower than category fluency across all groups.

Conclusions:

• Subcortical impairment and semantic memory deficits contribute to reduced verbal fluency in SCD and PD.
• Frontostriatal circuit and linguistic system disturbances likely cause initiation and retrieval problems in SCD's initial letter fluency.
• The cerebellar hemisphere may play a role in the rule-based generation of letters, influencing order and timing.