Objective: There is an evidence of central nervous system (CNS) involvement in diabetic patients. The aim of the study was to determine a conduction slowing in CNS pathways using a transcranial magnetic stimulation (TMS) and F-wave latency measurement.
Methods: Diabetic patients and a control group, both without clinical symptoms and signs of CNS lesion were evaluated. Motor evoked potentials were recorded from upper and lower extremities and central conduction time (CCT) was calculated according to formula: CCT = MEP-[0.5x(F-M-1)+M]. Obtained results and data from literature were compared.
Results: There was a significant prolongation of CCT recorded from lower extremities. The prolongation of CCT recorded from upper extremities was not statistically significant. Our results correlate with previously published data.
Conclusion: In spite of missing clinical signs of CNS lesion in diabetic patients, a significant prolongation of CCT compared to control group and literature data was recorded. We assume a presence of diffuse subclinical CNS lesion induced by metabolic changes in DM. Difference between CCT obtained from upper and lower extremities implicate, that changes are analogical to peripheral neuropathies ("central length-dependent injury?"). Measurement of CCT using TMS could become a complementary electrophysiological method for assessment of subclinical CNS involvement in diabetic patients. (Tab. 4, Ref. 17.)