Primary Position Upbeat Nystagmus during an Acute Attack of Multiple Sclerosis

BACKGROUND AND PURPOSE: Ocular manifestation is one of the frequent signs of an acute attack in multiple sclerosis (MS), although primary position upbeat nystagmus (PPUN) is rare. The purpose of this study is to determine the incidence of PPUN in MS and to determine the lesions that are responsible for this sign. METHODS: The medical records of 120 MS patients with acute brain lesions were reviewed over a consecutive period of 9 years; of these, 6 patients were found to have PPUN. Other ocular motor abnormalities were analyzed in combination with upbeat nystagmus, video-oculographic findings, and lesions detected on brain MRI. RESULTS: Lesions in the pontine tegmentum involving the medial longitudinal fasciculus (MLF) and ventral tegmental tract (VTT) were the most common, being observed in three of the six patients with PPUN. One patient exhibited caudal medullary lesions bilaterally affecting the paramedian portion of the posterior tegmentum, and two patients exhibited multiple lesions involving the pons with the cerebral peduncle or medulla. In five patients, other ocular motor dysfunctions, such as gaze-evoked nystagmus (n=3) and internuclear ophthalmoplegia (n=1), were found in combination with upbeat nystagmus. CONCLUSIONS: PPUN is an infrequent, ocular manifestation noted during an acute attack of MS, and was observed in 5% of the present cases. Brainstem lesions in these cases primarily involved the pontine tegmentum and the caudal medulla. These findings support the theory that upbeat nystagmus is attributable to damage to the upward vestibulo-ocular reflex pathway related to the vestibular nucleus, VTT, and interconnecting pathways.

EXPERIMENTAL MORPHOLOGIC STUDY ON THE ARTIFICIAL BLADDER REFLEX ARC ESTABLISHED BY ABDOMINAL REFLEX AFTER SPINAL CORDINJURY / 解放军医学杂志

To study the neural morphological basis of the "abdominal reflex spinal cord center bladder" artificial bladder reflex arc established by abdominal reflex. It is achieved by intradural microanastomosis of the right T 13 ventral root was anastomosed under microscope to S 2 ventral root by autogenous nerve grafting intraduraly, with the right T 13 dorsal root remaining intact and the right L 5 ～S 4 ventral roots severed. three to four months were allowed to achieve axonal regeneration, and new "abdominal reflex spinal cord center bladder" artificial bladder reflex pathway was established. Eight months after the operation, it was seen under light microscopy that regenerative nerve fibers of ventral root of T 12 had grown through the anastomotic site to distal nerve root. Under electron microscopy, nerve endings in the detrusor of the bladder were seen on the experimental side. The basic structure of the junction between parasympathetic nerve endings and bladder detrusor cells on the experimental side was similar to that on the control side. These features were not seen in the control group. The results suggested that the somatic motor axons above the lumbosacral paraplegia level could innervate bladder parasympathetic ganglion cells, and thereby transfersed somatic reflex activity to the bladder detrusor muscle, which was the morphological basis of the artificial bladder reflex arc leading to controllable micturition