The role of axonopathy in the mechanisms of development of demyelination processes in the central and peripheral nervous system.

The role of axonopathy in the development of demyelinating processes in the CNS and peripheral nervous system was addressed in studies of 43 patients with multiple sclerosis (MS) and 144 patients with chronic inflammatory demyelinating polyneuropathy (CIDPN). Patients with MS were found to have foci of reduced MRI intensity in the T1 regime ("black holes," present in 28%) and regional atrophy of the cerebral cortex (in 46%), which showed a significant association with the degree of invalidity on the EDSS (Kendall tau = 0.38 and 0.43; p = 0.038 and 0.021, respectively). The mean fatigue score on the FSS was 4.9 (3.6; 5.4). A significant increase in the central conduction time on the background of fatigue (p = 0.016), along with an absence of signs of impaired reliability of neuromuscular transmission and an absence of past-activation phenomena, suggested that central mechanisms were predominant in the formation of fatigue phenomena in MS. In addition, 34.9% of patients with MS showed signs of peripheral nervous system involvement, while the clinical-electrophysiological pattern in 12.5% of patients with CIDPN showed signs of CNS involvement. These data widen existing concepts of the mechanisms of formation of axonopathy in the CNS, based on evidence for the development of axon-demyelinating processes in CIDPN, which is the most accessible model of demyelination for study using contemporary neurophysiological methods.