Brainstem dysfunction protects against syncope in multiple sclerosis

BACKGROUND: The aim of this study was to investigate the correlation between autonomic dysfunction in multiple sclerosis (MS) and brainstem dysfunction evaluated with the vestibular evoked myogenic potentials (VEMP) score and conventional MRI. ----- METHODS: Forty-five patients with the diagnosis of clinically isolated syndrome (CIS) suggestive of MS were enrolled. VEMP, heart rate, and blood pressure responses to the Valsalva maneuver, heart rate response to deep breathing, and pain provoked head-up tilt table test, as well as brain and spinal cord MRI were performed. ----- RESULTS: There was no difference in the VEMP score between patients with and without signs of sympathetic or parasympathetic dysfunction. However, patients with syncope had significantly lower VEMP score compared to patients without syncope (p<0.01). Patients with orthostatic hypotension (OH) showed a trend of higher VEMP score compared to patients without OH (p=0.06). There was no difference in the presence of lesions in the brainstem or cervical spinal cord between patients with or without any of the studied autonomic parameters. The model consisting of a VEMP score of ≤5 and normal MRI of the midbrain and cervical spinal cord has sensitivity and specificity of 83% for the possibility that the patient with MS can develop syncope. ----- CONCLUSIONS: Pathophysiological mechanisms underlying functional and structural disorders of autonomic nervous system in MS differ significantly. While preserved brainstem function is needed for development of syncope, structural disorders like OH could be associated with brainstem dysfunction

Auditory evoked potentials and vestibular evoked myogenic potentials in evaluation of brainstem lesions in multiple sclerosis

OBJECTIVE: The aim of this study was to determine the roles of magnetic resonance imaging (MRI), auditory evoked potentials (AEP) and vestibular evoked myogenic potentials (VEMP) in the evaluation of brainstem involvement in multiple sclerosis (MS). ----- PATIENTS AND METHODS: Altogether 32 patients with the diagnosis of MS participated in the study. The following data was collected from all patients: age, gender, Expanded Disability Status Scale (EDSS) score, brainstem functional system score (BSFS) (part of the EDSS evaluating brainstem symptomatology), and involvement of the brainstem on the brain MRI. AEP and ocular VEMP (oVEMP) and cervical VEMP (cVEMP) were studied in all patients. ----- RESULTS: BSFS, MRI, AEP, oVEMP and cVEMP involvement of the brainstem was evident in 9 (28.1%), 14 (43.8%), 7 (21.9%), 12 (37.5%) and 10 (31.0%) patients, respectively. None of the tests used showed statistically significant advantage in the detection of brainstem lesions. When combining oVEMP and cVEMP 18 (56.3%) patients showed brainstem involvement. This combination showed brainstem involvement in greater percentage than BSFS or AEP, with statistical significance (p=0.035 and p=0.007, respectively). ----- CONCLUSION: VEMP is a reliable method in detection of brainstem involvement in MS. It is comparable with MRI, but superior to clinical examination or AEP

Correlation of the VEMP score, ambulation and upper extremity function in clinically isolated syndrome

OBJECTIVE: To investigate the correlation of the vestibular evoked myogenic potential (VEMP) score with Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT), Paced Auditory Serial Addition Test (PASAT) and EDSS in patients with multiple sclerosis (MS). ----- METHODS: This prospective, cross sectional study included 52 patients with clinically isolated syndrome (CIS). Cervical VEMP (cVEMP) and ocular VEMP (oVEMP), analyzed in the form of the cVEMP, oVEMP and VEMP scores, T25FW, 9HPT, PASAT and Expanded Disability Status Scale (EDSS) were performed. ----- RESULTS: The only predictor of walking impairment in this study was general disability as measured by the EDSS, after controlling for age, gender, PASAT and EDSS the effect of VEMP score was non-significant (p=0.419). 9HPT of the dominant hand did not correlate with the oVEMP score (rs=0.258, p=0.065), however after controlling for age, gender, PASAT and EDSS, the effect of the oVEMP score on 9HPT of the dominant hand was statistically significant (p=0.017). After controlling for age, gender and oVEMP score, the effect of the PASAT on 9HPT variable for the non-dominant hand was statistically significant (p=0.001). ----- CONCLUSION: We found possible effects of brainstem dysfunction on walking impairment, however they were not seen after correction for EDSS and cognitive dysfunction. On the other hand, dominant hand function seems to be influenced by upper brainstem dysfunction measured with oVEMP, while cognitive dysfunction is related to non-dominant hand function

Association of autonomic nervous system abnormalities on head-up tilt table test with joint hypermobility

AIM: The aim of this study was to investigate the association of autonomic nervous system abnormalities on head-up tilt table test (HUTT) with generalized joint hypermobility, expressed by Beighton score (BS). ----- METHODS: This was a prospective study that included 115 consecutive patients (91 females; mean age 34.35 ± 14.11) referred either for the HUTT or testing of the cardiovascular autonomic reflexes together with HUTT. Generalized joint hypermobility was evaluated according to the BS system after which HUTT was performed. Clinically significant BS was considered if ≥4. ----- RESULTS: Fifteen patients (15.1%) had BS ≥4. Results of the HUTT were normal in 58 (50.4%) patients and in 57 (49.6%) patient HUTT was abnormal. Fifteen (13.0%) patients fulfilled criteria for orthostatic hypotension, 30 (26.1%) for reflex syncope and 21 (18.3%) for postural orthostatic tachycardia syndrome. Patients with pathological findings on HUTT had significantly higher BS compared to patients with normal HUTT (median 1 vs. 0, p = 0.001). There was a significant association between participants with BS ≥4 and pathological HUTT (χ[1] = 6.392, p = 0.011). Results of the multivariate regression analysis revealed that increase in the BS is associated with the increased likelihood of HUTT pathology (Exp[B] 1.44, 95% CI 1.084-1.922, p = 0.012), while increase in age is associated with lower risk of HUTT pathology (Exp[B] 0.968, 95% CI 0.939-0.998, p = 0.036). ----- CONCLUSION: There is an association between autonomic nervous system abnormalities on HUTT test and generalized joint hypermobility

Video head impulse test can detect brainstem dysfunction in multiple sclerosis

BACKGROUND: The aim of this study was to investigate the potential role of video head impulse test (vHIT) in the detection of brainstem lesions in patients with multiple sclerosis (MS). ----- METHODS: Sixty-eight participants were enrolled and divided into two groups: 39 healthy subjects (HC) (78 ears, 20 females, mean age 25,3±6,3) and 29 MS patients (58 ears, 14 females, mean age 33,7±7,7). Both groups underwent vHIT, and in MS group MRI was analyzed for the presence of brainstem lesions. vHIT pathology was defined as presence of overt saccades (<200ms) or lateral gain lower than 0.8 for lateral canal, and presence of overt saccades (<200ms) or posterior/anterior slope lower than 0.7. ----- RESULTS: In HC, decreased gain on horizontal canals was found in 8 out of 78 ears (11%), while 16 out of 58 ears (38%) had pathological results in the MS group. Mean gain of the lateral canals (60ms) was significantly reduced in MS group compared to HC (0.874±0143 vs. 0.954±0,170, p=0.004, respectively). Compared to HC overt saccades 200ms in lateral (p<0.001), anterior (p=0.019) and posterior canals (p=0.009), and covert saccades in the anterior (p=0.042) and posterior canals (p=0.046) were more frequent in the MS group. There was statistically significant association between the presence of BS MR lesions and bilateral pathology on vHIT for lateral semicircular canal (χ(1)=3.982, p=0.046). ----- CONCLUSION: These results indicate that vHIT can detect brainstem dysfunction in patients with MS