The Effect of Diabetes on Cortical Function in Stroke: Implications for Poststroke Plasticity.
Diabetes may impair the capacity for neuroplasticity such that patients experience a slower and poorer recovery after stroke. The current study investigated changes in cortical function in stroke patients with diabetes to determine how this comorbidity may affect poststroke cortical plasticity and thereby functional recovery. From a cohort of 57 participants, threshold-tracking transcranial magnetic stimulation was used to assess cortical function over the ipsilateral and contralesional hemispheres in 7 patients with diabetes after an acute stroke compared with 12 stroke patients without diabetes. Cortical function was also assessed in 8 patients with diabetes without stroke and 30 normal control subjects. After acute stroke, short-interval intracortical inhibition (SICI) was reduced over both motor cortices in stroke patients without diabetes compared with normal control patients, while in stroke patients with diabetes, SICI was only reduced over the contralesional but not the ipsilesional cortex compared with control patients with diabetes. In addition, SICI was significantly reduced in the control patients with diabetes compared with normal control patients. These results have demonstrated the absence of ipsilesional cortical excitability change after diabetic strokes, suggesting impaired capacity for neuroplasticity over this hemisphere as a consequence of a "double-hit" phenomenon because of preexisting alterations in cortical function in nonstroke patients with diabetes. The reliance on reorganization over the contralesional cortex after stroke will likely exert influence on poststroke recovery in patients with diabetes.
Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia w.huynh@neura.edu.au.|Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia.
William
0000-0002-6504-8107
W
Huynh
School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
Natalie
N
Kwai
School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
Ria
R
Arnold
Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia.
Arun V
AV
Krishnan
School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
Cindy S-Y
CS
Lin
Westmead Clinical School, University of Sydney, Sydney, New South Wales, Australia.
Steve
S
Vucic
Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia.
Matthew C
MC
Kiernan
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D009433:Neural Inhibition; D009473:Neuronal Plasticity; D020127:Recovery of Function; D020521:Stroke / Q000150:complications / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation