ELECTRONEUROPHYSIOLOGICAL PARAMETERS OF THE BRAIN IN PATIENTS WITH CHIARI MALFORMATION BEFORE AND AFTER SURGERY

Objective. The impartial instrument assessment of a nature and degree of cephalic and cervical spinal cord functional abnormalities and dynamics of their changes in patients with Chiari malformation before and after surgery. Material and Methods. Visual evoked potentials (VEP), somatosensory (SSEP) and brainstem auditory evoked potentials (BAEP), and motor responses to the transcranial magnetic stimulation (TMS) were registered in 28 patients preoperatively and in 12–30 days postoperatively. Results. Initial VEP and SSEP showed deviations from normal values caused by hydrocephalus and increased intracranial pressure. In majority of patients a latent time of VEP P100 was abnormally short. Lateral asymmetries of P100 delay and amplitude, and VEP shape changes were also observed. P100 delays increase and VEP asymmetry were observed when foci of vascular dysmetabolic genesis and dystrophic changes were present. SSEP had changes in N30 cortical components. Initial N20 components were radically changed only in patients with cervical syringomyelia. The same patients had the worst M-responses to the TMS. BAEP were registered with decreased V component and increased interpeak IV–V interval. Conclusion. Arnold – Chiari syndrome is reflected in various deviations of electrophysiological parameters characterizing a functional condition of the central nervous system. Postoperative dynamics showed prevalence of positive shifts and normalization of electrophisiological parameters