Comparison of brainstem reflex abnormalities in patients with multiple sclerosis, Behçet and stroke and its topodiagnostic value

Abstract

Background Our current understanding of brainstem reflex physiology comes chiefly from the classic anatomical–functional correlation studies that traced the central circuits underlying brainstem reflexes and establishing reflex abnormalities as markers for specific areas of lesion. Our aim is to investigate the correlation between the brainstem reflex abnormalities and lesion localization in three different diseases with brainstem lesions. Methods Masseter inhibitory and blink reflexes were studied in 21 multiple sclerosis, 15 stroke and 17 Behcet’s disease patients with brainstem lesions on brain magnetic resonance imagings. The reflex responses were compared with those of 20 healthy subjects of comparable age. SPSS for Windows 11.5 package was employed for statistical processing. Results Latency abnormalities of the blink and the masseter inhibitory reflexes were the most prominent in MS group. No significant differences were found in duration and degree of suppression among the groups in MIR responses. The highest abnormality percentages in MS group were in R1component of blink reflex (% 71, 4) and S2 component of masseter inhibitory reflex (% 90, 5). And also R1 of BR and S2 of MRI were the most abnormal responses in the all groups compared to other parameters. Conclusions Distinct reflex abnormalities indicate lesions at specific sites. A number of lesions suspected on clinical data may be confirmed by reflex findings only and not by imaging studies. Reflex testing can be utilized to demonstrate multiple lesions and evaluate dissemination of central nervous involvement in patients with brainstem lesions. Increased abnormality percentage in MS group may be explained by the fact that supratentoriel lesions affect brainstem reflex responses. Since lesions in Behcet’s disease are localised in mesencephalon commonly, superior to MIR and BR circuits, the abnormality in this group is much less relatively.