Demyelinating Brain Stem Lesions Research Articles

Cervical vestibular evoked myogenic potentials and video head impulse test studies: alternative methods for detecting brainstem involvement in multiple sclerosis

Background Brainstem involvement (BSI) has been reported as a major predictive factor for future disability in Multiple Sclerosis (MS). Aims/Objectives To evaluate whether Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) and Video Head Impulse Test (vHIT) can be used to detect demyelinating lesions in vestibular pathways in MS. Material and Methods Fifty three people with MS and 40 controls were evaluated with Dizziness Handicap Inventory (DHI), vHIT and cVEMP. Results The median value of DHI in MS group was significantly higher than controls (p<.001). According to vHIT results, while the results of horizontal canal vestibulo-ocular reflex gain in group with brain stem involvement (gBSI (+)) were significantly different from both controls and group without brain stem involvement (gBSI (−)) (p= .036 and .024, respectively), results of gBSI (−) were similar with controls (p= .858). When cVEMP results were examined, mean P1 wave latency in gBSI (+) was significantly longer than controls (p= .002), but difference between gBSI (−) and controls and gBSI (+) was not statistically significant (p= .104 and .279, respectively). Conclusions and Significance vHIT and cVEMP can be used in diagnosis and follow-up of people with MS without demyelinating brainstem lesions on MRI.

Operative findings and outcome of microvascular decompression/adhesiolysis for trigeminal neuralgia in multiple sclerosis without demyelinating brain stem lesions

ObjectiveTrigeminal neuralgia (TN) in multiple sclerosis (MS) poses several challenges for treatment. Although these patients often have typical attacks, they may not be considered as candidates for microvascular decompression (MVD). Here we report on surgical findings and long term follow-up of MVD/ adhesiolysis in a series of patients with multiple sclerosis but without demyelinating brain stem lesions. MethodsFifteen patients with MS-related TN underwent MVD/ adhesiolysis. Demyelinating brain stem lesions were excluded radiologically. Outcome of the intervention was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at 3, 12, 24 months follow-up and at the last available follow-up (mean 88.2 months, range 38–146). ResultsAll 15 patients benefited from MVD/adhesiolysis and were pain free on the first day of surgery. Intraoperative findings included arterial contact in 7/15 (47 %) patients, venous contact in 9/15 (60 %), and prominent arachnoid thickening in 12/15 (80 %). The distribution of the BNI pain intensity scores showed marked improvement at all follow-up evaluations. Five patients underwent repeat MVD/adhesiolysis for pain recurrence at a mean of 43 months after the first surgery. Long term evaluation at the last available follow-up demonstrated favorable outcome in 13/15 patients (BNI I-IIIa) (87 %), while 2/15 patients had limited benefit (BNI IV). ConclusionsMS-related TN in patients without demyelinating brain stem lesions may be related either to vascular conflicts or to focal arachnoiditis at the trigeminal nerve entry zone. MVD/ adhesiolysis may be considered as a useful treatment option in this subgroup of patients with regard to long term outcome.

Clinical Course of Patients With Ophthalmoplegia Caused by Radiographically Detectable Brainstem Demyelination Occurring as a Clinically Isolated Demyelinating Syndrome

Demyelinating brainstem lesions often causing ophthalmoplegia may occur as the first manifestation of a clinically isolated demyelinating syndrome (CIS). CIS could be the initial attack of clinically definite multiple sclerosis (CDMS) should a second symptomatic attack occur. We report a series of patients with ophthalmoplegia occurring as CIS and assess potential factors affecting the clinical course and final outcome. A computer search was performed for patients evaluated in a university academic neurology practice to identify those with the diagnosis of diplopia. Selection was then made of patients who met the criteria for CIS, and these individuals formed the basis of this study. Ten of 327 patients presenting with diplopia fulfilled inclusion criteria. Of these, all had ophthalmoplegia in primary position of gaze or symptomatic internuclear ophthalmoplegia, and all recovered irrespective of brain MRI findings, steroid use, presence of oligoclonal bands, or progression to CDMS. The ophthalmoplegia of CIS tends to improve with time, regardless of later progression to CDMS. More analysis is needed to fully understand this unique presentation of demyelination.

Isolated cranial nerve palsies due to brainstem lesions

Isolated cranial nerve palsies are often attributed to lesions of the respective nerves along their extraaxial courses. There are a significant number of reports of individual patients with cranial nerve palsies, mostly of the 3rd and 6th nerves, as the sole manifestation of brainstem lesions proven by magnetic resonance imaging (MRI) or computer-assisted tomography (CT). An intraaxial basis may still be underestimated if based on MRI only, as electrophysiological abnormalities indicating brainstem lesions (masseter reflex, blink reflex, DC electrooculography) may be independent from MRI-documented morphological lesions. This article reviews the evidence that ischemic and demyelinating brainstem lesions are an important and underestimated cause of clinically isolated cranial nerve palsies. Especially in middle-aged and elderly people with 3rd and 6th nerve palsies, small pontine and mesencephalic infarctions seem to be more frequent than small-vessel ischemic infarctions of the extraaxial nerves.

Isolated sixth-nerve palsy as the presenting sign of multiple sclerosis

The author reports a young patient presenting isolated (fascicular) abducens nerve palsy as the only and first sign of multiple sclerosis. Whereas diplopia-a common symptom of multiple sclerosis-is usually due to supranuclear brainstem dysfunction, it is rarely caused by sixth-nerve palsy. In larger series analysing the aetiologies of sixth-nerve palsies, multiple sclerosis was a rare cause, particularly in the case of isolated sixth-nerve palsy. However, these studies were done decades ago when adequate imaging procedures were not available. Nowadays, the large group with undetermined cause should shrink when appropriate diagnostic work-up such as application of MRI is performed. This case demonstrates that demyelinating brainstem lesions with appropriate location in the course of the sixth-nerve fascicle may cause isolated sixth-nerve palsy.