Adults with diabetic peripheral neuropathy exhibit impairments in multitasking and other executive functions.

BACKGROUND AND
PURPOSE: Diabetic peripheral neuropathy (DPN) contributes to functional impairment, and there is growing evidence that neuropsychological factors also influence physical function. We compared cognitive and executive function in adults with DPN with an age-matched comparison group, and examined the relationships between DPN, executive function, and physical function.
METHODS: Twenty subjects with DPN and 20 comparison subjects were assessed. Diabetic peripheral neuropathy was quantified via the Michigan Neuropathy Screening Instrument and nerve conduction velocity testing. Subjects were administered Beck's Depression Inventory, the Mini-Mental Status Examination, and the Timed Up and Go (TUG) test. Each participant also completed a battery of 7 executive function tasks, including the Cognitive Timed Up and Go (cTUG) test, in which a concurrent mental subtraction task was added to the standard TUG test.
RESULTS: The DPN group demonstrated poorer letter fluency (34.2 ± 11.6 words vs 46.2 ± 12.2 words; P = 0.001), category fluency (47.0 ± 8.1 words vs 56.3 ± 8.5 words; P = 0.003), and Rey-Osterrieth scores (25.9 ± 4.3 points vs 31.7 ± 2.4 points; P < 0.001), and took longer to complete both the TUG (10.3 ± 2.8 seconds vs 5.9 ± 1.0 seconds; P < 0.001) and cTUG (13.0 ± 5.8 seconds vs 6.9 ± 1.6 seconds; P < 0.001). Poorer global cognitive performance and greater depression symptoms were significantly related to each other (r = -0.46; P = 0.04) and to slower TUG times (r = -0.53; P = 0.02; and r = 0.54; P = 0.02, respectively). DISCUSSION AND
CONCLUSIONS: Verbal, visuospatial, and multitasking measures of executive function may be impaired in adults with DPN. Future research should examine how these and other cognitive and psychological factors, such as depression, affect physical function in this population.