Subclinical central nuropathy in thype 2 diabetes mellitus

ABSTRACT

Involvement of the peripheral and autonomic nervous systems is frequently encountered in diabetes mellitus [DM]. However, there is a paucity of data regarding central neuropathy in DM. To evaluate central nervous system neuropathic changes in patients with type 2 DM with and without peripheral neuropathy. The study included three groups; group 1 Fifteen patients with type 2 DM with clinical and electrophysiological findings of peripheral neuropathy, group 2 Fifteen patients with type 2 DM without any clinical or electrophysiological evidence of peripheral neuropathy and group 3 Fifteen healthy subjects as a control group. All groups were age and sex matched and subjected to physical examination, laboratory investigations including Complete blood cell count, fasting plasma glucose. glycated hemoglobin [HbAlc], serum lipid profile, renal fitnctions and other necessary tests, in addition to the electrophysiological study including Somatosensory evoked potentials [SEP], motor evoked potentials [MEP], visual evoked potentials [VEP] and brainstein auditory evoked potentials [BAEP]. Group I had a statistically significant higher mean values of fasting plasma glucose, HbAlc, urinary albumin excretion [UAE] and serum creatinine compared with group 2. Both diabetic groups had similar changes in VEP P100 latency and its amplitude, MEF central motor conduction time, amplitude percentage quotient and duration of the MEP, and BAEP wave II latency, with statistically significant differences compared to healthy controls. There was a statistically significant delay in all of the BAEP waves interpeak latency only in group 1. The other tested parameters of central neuropathy showed statisticasly signficant differences between all studied groups. A statistically significant positive correlation was observed between some of the studied parameters of central neuropathy in diabetic patients and each of the patient age, duration of diabetes, HbA1c, serum total cholesterol, serum triglycerides and UAE. Central neuropathy in type 2 diabetics is not uncommon even in absence of peripheral neuropathy. It is related to the patient age, duration of diabetes, glycated hemoglobin value, dyslipidemia and diabetic nephropathy. The use of more than one modality of the electrophysiological tests [multimodal evoked potential studies] can buffer the fallacies of a single mode and is advisable in evaluating central neuropathy in patients with type 2 DM. Early diagnosis of central neuropathy is recommended to offer an early opportunity for a proper management