Balance in multiple sclerosis: relationship to central brain regions.

Dizziness, postural instability, and ataxia are among the most debilitating symptoms of multiple sclerosis (MS), reflecting, in large part, dysfunctional integration of visual, somatosensory, and vestibular sensory cues. However, the role of MS-related supratentorial lesions in producing such symptoms is poorly understood. In this study, motor control test (MCT) and dynamic sensory organization test (SOT) scores of 58 MS patients were compared to those of 72 healthy controls; correlations were determined between the MS scores of 49 patients and lesion volumes within 26 brain regions. Depending upon platform excursion direction and magnitude, MCT latencies, which were longer in MS patients than controls (p < 0.0001), were correlated with lesion volumes in the cortex, medial frontal lobes, temporal lobes, and parietal opercula (r's ranging from 0.20 to 0.39). SOT test scores were also impacted by MS and correlated with lesions in these same brain regions as well as within the superior frontal lobe (r's ranging from - 0.28 to - 0.40). The strongest and most consistent correlations occurred for the most challenging tasks in which incongruent visual and proprioceptive feedback were given. This study demonstrates that supratentorial lesion volumes are associated with quantitative balance measures in MS, in accord with the concept that balance relies upon highly convergent and multimodal neural pathways involving the skin, muscles, joints, eyes, and vestibular system.

Streamlining the Cochlear Implant Evaluation: Utility of Community Audiometry in Cochlear Implant Candidacy Assessment.

OBJECTIVE: To identify redundancy in the cochlear implant candidacy evaluation and assess its financial impact. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care academic cochlear implant center. PATIENTS: One hundred thirty-five patients referred for cochlear implant candidacy evaluation from 2004 through 2019. INTERVENTION: Community and academic audiometry were compared in a matched-pair analysis. MAIN OUTCOME MEASURES: Pure-tone audiometry and word recognition scores (WRS) were compared using the Wilcoxon signed-rank test. Cost of repeated audiometry was estimated using the Medicare Provider Utilization and Payment data. RESULTS: The majority of pure-tone thresholds (PTT) and pure-tone averages (PTA) had no statistically significant differences between community and academic centers. Only air PTT at 2000 Hz on the right and air PTA on the right demonstrated differences with α = 0.05 after Bonferroni correction. Despite statistical differences, mean differences in PTT and PTA were all under 3.5 dB. WRS were on average lower at the academic center, by 14.7% on the right (p < 0.001) and 10.6% on the left (p = 0.003). Repeating initial audiometry costs patients up to $60.58 and costs the healthcare system up to $42.94 per patient. CONCLUSIONS: Pure-tone audiometry between community and academic centers did not demonstrate clinically significant differences. Lower academic WRS implies that patients identified as potential cochlear implant candidates based on community WRS are likely suitable to proceed to sentence testing without repeating audiometry, saving patients and the healthcare system time and resources.

Head shake computerized dynamic posturography in peripheral vestibular lesions.

PURPOSE: To determine the sensitivity of a head shake modification to the Sensory Organization Test (SOT) of dynamic posturography in identifying (a) those patients with unilateral, peripheral vestibular hypofunction as indicated by caloric irrigation findings and (b) those patients who report that head movements provoke disruption in postural control. METHOD: A prospective, single-blinded, random selection methodology was used with 91 patients stratified by the presence or absence of a significant caloric asymmetry and by the presence or absence of head movement provoked symptoms (independent variables). Postural control performance, as measured by EquiTest during the standard test and a head shake modification, served as the dependent variables. RESULTS: Receiver operating characteristic curves demonstrated only minor improvement in sensitivity (a) with the head shake modification for unilateral peripheral asymmetry and (b) for identification of those with complaints of head movement provoked imbalance. CONCLUSIONS: The head shake modification to standard SOT increased the test sensitivity to identification of patients with unilateral, peripheral vestibular hypofunction and those with head movement provoked symptoms. However, this occurred with low specificity, resulting in no significant improvement in overall performance with this head shake protocol. Suggestions for further research to improve the performance of the head shake modification of SOT for clinical application are discussed.

Pure-tone auditory thresholds are not chronically elevated in multiple sclerosis.

Despite the fact that acute cases of multiple sclerosis (MS)-related pure-tone hearing loss have been reported in the literature, consensus is lacking as to the chronic influences of MS on pure-tone thresholds. Most studies examining such influences have been limited by small sample sizes, lack of statistical comparisons between patients and controls, and confounding of the hearing measure with influences from sex and age. To date, associations between pure-tone thresholds and central MS-related brain lesions have not been assessed. In this study, pure-tone thresholds ranging from 0.5 to 8 kHz were measured in 73 MS patients and 73 individually age- and gender-matched normal controls. In 63 MS patients, correlations were computed between the threshold values and MRI-determined lesion activity in 26 central brain regions. Although thresholds were strongly influenced by sex, age, and tonal frequency, no meaningful influences of MS were discerned. Moreover, no significant association between the threshold values and central MS-related lesion activity was evident in any brain region evaluated. This study, the largest on this topic to use carefully matched control subjects and the sole study to assess relationships between auditory thresholds and central MS-related lesions, strongly suggests that (a) MS is not chronically associated with pure-tone hearing loss and (b) pure-tone thresholds are unrelated to MS lesion activity in higher brain regions. These findings, along with general reports from the literature, support the concept that when MS-related hearing threshold deficits are found, they are episodic and primarily dependent on lesions within the eighth nerve or brainstem.