Vestibular evoked myogenic potential for diagnoses of multiple sclerosis: is it beneficial?

AIM: To determine the sensitivity of the vestibular evoked myogenic potential (VEMP) in multiple sclerosis (MS) patients as well as its relation to clinical signs and symptoms, course of the disease and other evoked potentials. METHODS: This case-control study was conducted on 40 subjects (20 MS patients and 20 healthy participants). Participants were selected from Imam Khomeini Hospital, Tehran, Iran. Two hundred stimuli (clicks of 0.1 ms of duration and 2 Hz frequency) were applied to each ear. These stimuli were repeated in two consecutive cycles. In order to evaluate the reproducibility the stimulation intensity of 95dBNHL was applied. During the test, individuals were requested to be seated on a chair and rotate their head to the opposite side of the stimulated ear to activate the ipsilateral sternocleidomastoid muscle (SCM). RESULTS: A biphasic, initially positive, p13-n23 wave pattern was found in all patients. All of the parameters, including latencies and amplitudes fit the normal Kolmogorov-Smirnov (KS) distribution. Fourteen (70%) patients reported abnormal results, and VEMP abnormality was significantly related to disease duration also. In addition, there was a significant correlation between abnormality of VEMP and abnormality of visual evoked potential (VEP) as well as the abnormality of VEMP and brainstem auditory evoked potential (BAEP). CONCLUSION: Vestibular evoked myogenic potential has a high sensitivity (70%) in MS patients, and VEMP could be recommended as a useful complementary neurophysiological method to evaluate the MS patients.

Could Helicobacter pylori play an important role in axonal type of Guillain-Barré syndrome pathogenesis?

In this case-control study, ELISA and Western blot with whole bacterial protein lysate were performed on serum and cerebrospinal fluid (CSF) of 15 controls and 15 patients. According to Griffin subtypes, 10 of our patients were in acute inflammatory demyelinating polyradiculoneuropathy (AIDP) group, 3 in acute motor axonal neuropathy (AMAN) group, and 2 in acute motor sensory axonal neuropathy (AMSAN) subtype. 86.6% of patients were positive for Helicobacter pylori (H. pylori) IgG. Serum anti-H. pylori IgG of patients and controls were significantly different. CSF anti-H. pylori IgG was significantly higher in patients than controls. In patients, the titer of anti-H. pylori IgG in serum was significantly higher than CSF, which may indicate extra-neural antibody synthesis. CSF IgG titer was higher in patients having axonal pattern. Western blot was positive in CSF of 13 patients and negative in all controls. There was a correlation between the number of antibody types against H. pylori particles and the titer of anti-H. pylori IgG in CSF and serum. Also, antibody against cytotoxin associated protein (CagA) was associated with primary axonal pattern. The association between the presence of anti-CagA and primary axonal pattern, is in favor of the relation between axonal neuropathy and H. pylori infection.