Did you know posterior fossa lesions in MS portend a poor prognosis? #MSBlog #MSResearch #ClinicSpeak
"The brainstem is the part of the central nervous system (CNS) between the spinal cord and so called cerebral hemispheres. The brainstem is like a very busy railway junction with many fibre tracts (axons) passing through it on the way to the spinal cord and back from the spinal cord to the brain. In addition, it houses many of the so called autonomic centres that control breathing, blood pressure, pulse rates and swallowing. The brain stem also houses the centres for eye movements, hearing, balance, coordination, walking and the nerve cell bodies of most of the cranial nerves. The brainstem is also closely linked to the cerebellum or mini-brain that controls many motor functions. The brainstem and cerebellum are housed in the so called posterior fossa of the skull. When MS lesions occur in the posterior fossa, i.e. brainstem and cerebellum, they are frequently symptomatic and can be very devastating. MSers with posterior fossa disease have a far worse outcome than those without lesions in this area. I personally include posterior fossa signs in my crude prognostic index when advising patients about DMTs. Do you have posterior fossa disease? If you have had an MRI you should ask your neurologist if you have any lesions in the posterior fossa."
"The following is a list of symptoms that can be associated with posterior fossa involvement in MS; double vision, oscillopsia (jumping images), jerky eye movements, unsteady gait, incoordination, vertigo, tinnitus, deafness, hyperacusis, nausea, vomiting, hiccoughs, slurred speech, swallowing problems, choking, loss of taste, loss of sensation on the face or in the mouth, emotional incontinence or inappropriate crying or laughing and rarely hallucinations (pontine hallucinosis). More recently we have begun to identify cognitive impairment been linked to disease of the cerebellar hemispheres; typically MSers with severe cerebellar dysfunction have poor memory and the temporal sequencing of memories. When you talk to them they are come across as being very vague. As many fibre tracts pass through the brainstem weakness of the limbs, loss of sensation on the body, bowel, bladder and sexual problems can also occur from brainstem disease. It is clear that the brain stem is a very important structure and needs to be protected from the ravages of MS wherever possible."
"The study below uses a new neurophysiological technique to assess brainstem function. Unsurprisingly, they show that MSers with brainstem involvement have more disability. It would be interesting to see in future studies if this technique could be used as part of a surrogate outcome to monitor MS progression, specifically of the brainstem."
"Please note that brainstem disease may be linked to sudden unexplained death in MS (SUDMUS), which I have posted on before."
BACKGROUND AND PURPOSE: Concerning the great importance of brainstem involvement in MS, the aim of this study was to explore the role of the newly developed vestibular evoked myogenic potentials (VEMP) score as a possible marker of brainstem involvement in MSers.
PATIENTS AND METHODS: This was a prospective case-control study which included 100 MSers divided into two groups (without and with clinical signs of brainstem involvement) and 50 healthy controls. Ocular VEMP (oVEMP) and cervical VEMP (cVEMP) measurements were performed in all participants and analyzed for latencies, conduction block and amplitude asymmetry ratio. Based on this the VEMP score was calculated and compared with Expanded Disability Status Scale (EDSS), disease duration and magnetic resonance imaging data.
RESULTS: MSers with clinical signs of brainstem involvement (group 2) had a statistically significant higher percentage of VEMP conduction blocks compared with MSers without clinical signs of brainstem involvement (group 1) and healthy controls (P = 0.027 and P < 0.0001, respectively). Similarly, the VEMP score was significantly higher in group 2 compared with group 1 (P = 0.018) and correlated with EDSS and disease duration (P = 0.011 and P = 0.032, respectively). Multivariate linear regression analysis showed that the VEMP score has a statistically significant influence on the EDSS score (P < 0.001, R2 = 0.239).
CONCLUSIONS: Interpretation of the oVEMP and cVEMP results in the form of the VEMP score enables better evaluation of brainstem involvement than either of these evoked potentials alone and correlates well with disability.