Long-latency reflexes and cortical relay time in patients with Behçet?s disease

Objective: Behçet?s Disease (BD) is a multi-system inflammatory disease with a basic pathological characteristic of vasculitis. Neurological involvement was reported at a rate of %5-49 in various studies. Early diagnosis and proper treatment were emphasized to be significant in preventing the progression of the involvement of central neurological system (CNS). Recent studies have shown that subclinical neurological involvement is possible in BD patients which predominantly affects the motor pathway. Cortical relay time (CRT) calculated by long latency reflex II (LLR II) is considered to reflect the central transcortical conduction time of LLR II. While LLR II response provides information about the integrity of both descending and ascending neural pathways. Based on this information, the primary purpose of this study was to examine how the LLR II and CRT are affected in BD patients with out clinical neurological involvement. Methods: 37 BD patients with out neurological symptoms and findings were involved in the study. LLR II, somatosensory evoked potential (SEP) and motor evoked potential (MEP) studies were performed on bilateral abductor pollicis brevis muscles and median nerves in all patients. The difference between LLR II and H reflex latencies was calculated using the onset latency of H reflex obtained by the LLR II study. In addition, central sensory conduction time (CSCT) was calculated by substracting the peak latency of cervical SEP from the peak latency of cortical SEP. Central motor conduction time (CMCT) was calculated by the onset latency of cervical SEP from the onset latency of cortical SEP. CRT was calculated by subtracting the sum of cortical SEP (N20) peak latency and cortical MEP onset latency from LLR II onset latency. The data obtained was compared to the data obtained from 22 healthy controls. Results: No statistically significant difference was found between the two groups in H reflex onset latencies, N20 peak latencies, CSCT, cortical MEP onset latencies and CMCT (p?0.05). On the other hand, LLR II onset latency, the difference between LLR II?H reflex latencies and CRT values were found to be significantly higher in Behçet?s group (p<0,001, p<0,001 and p=0,003, respectively). Conclusion: LLR II, the difference between LLR II- H reflex latencies and CRT can be the leading parameters in the evaluation of subclinical neurological involvement in BD.