Reduced Purposeful Head Movements During Community Ambulation Following Unilateral Vestibular Loss.

BACKGROUND: Individuals with unilateral vestibular hypofunction (UVH) alter their movement and reduce mobility to try to stabilize their gaze and avoid symptoms of dizziness and vertigo. OBJECTIVE: To determine if individuals with UVH 6 weeks after surgery demonstrate altered head and trunk kinematics during community ambulation. METHODS: A total of 15 vestibular schwannoma patients with documented postoperative unilateral vestibular loss and 9 healthy controls with symmetrical vestibulo-ocular reflexes participated in this cross-sectional study. Head kinematics (head turn frequency, amplitude, and velocity) and head-trunk coordination during community ambulation were obtained from inertial measurement units for all head movements and within specific amplitudes of head movement. RESULTS: Individuals with UVH made smaller (mean 26° [SD = 3°] vs 32° [SD = 6°]), fewer (mean 133 [SD = 59] vs 221 [SD = 64]), and slower (mean 75°/s [SD = 8°/s] vs 103°/s [SD = 23°/s]) head turns than healthy individuals ( P < .05) but did not demonstrate significantly increased head-trunk coupling (mean 38% [SD = 18%] vs 31% [SD = 11%], P = .22). When small (≤45°) and large (>45°) head turns were considered separately, individuals with UVH demonstrated increased head-trunk coupling compared with healthy individuals for large head turns (mean 54% [SD = 23%] vs 33% [SD = 10%], P = .005). CONCLUSIONS: This study demonstrated that although walking at an adequate speed, individuals with UVH made fewer, smaller, and slower head movements symmetrically in both directions compared with healthy individuals and did not decouple their head movement relative to their trunk when required to make larger purposeful head turns during community ambulation.

Characterization of Head-Trunk Coordination Deficits After Unilateral Vestibular Hypofunction Using Wearable Sensors.

Importance: Individuals with vestibular hypofunction acutely restrict head motion to reduce symptoms of dizziness and nausea. This restriction results in abnormal decoupling of head motion from trunk motion, but the character, magnitude, and persistence of these deficits are unclear. Objective: To use wearable inertial sensors to quantify the extent of head and trunk kinematic abnormalities in the subacute stage after resection of vestibular schwannoma (VS) and the particular areas of deficit in head-trunk motion. Design, Setting, and Participants: This cross-sectional observational study included a convenience sample of 20 healthy adults without vestibular impairment and a referred sample of 14 adults 4 to 8 weeks after resection of a unilateral VS at a university and a university hospital outpatient clinic. Data were collected from November 12, 2015, through November 17, 2016. Exposures: Functional gait activities requiring angular head movements, including items from the Functional Gait Assessment (FGA; range, 1-30, with higher scores indicating better performance), the Timed Up & Go test (TUG; measured in seconds), and a 2-minute walk test (2MWT; measured in meters). Main Outcomes and Measures: Primary outcomes included peak head rotation amplitude (in degrees), peak head rotation velocity (in degrees per second), and percentage of head-trunk coupling. Secondary outcomes were activity and participation measures including gait speed, FGA score, TUG time, 2MWT distance, and the Dizziness Handicap Inventory score (range, 0-100, with higher scores indicating worse performance). Results: A total of 34 participants (14 men and 20 women; mean [SD] age, 39.3 [13.6] years) were included. Compared with the 20 healthy participants, the 14 individuals with vestibular hypofunction demonstrated mean (SD) reduced head turn amplitude (84.1° [15.5°] vs 113.2° [24.4°] for FGA-3), reduced head turn velocities (195.0°/s [75.9°/s] vs 358.9°/s [112.5°/s] for FGA-3), and increased head-trunk coupling (15.1% [6.5%] vs 5.9% [5.8%] for FGA-3) during gait tasks requiring angular head movements. Secondary outcomes were also worse in individuals after VS resection compared with healthy individuals, including gait speed (1.09 [0.27] m/s vs 1.47 [0.22] m/s), FGA score (20.5 [3.6] vs 30.0 [0.2]), TUG time (10.9 [1.7] s vs 7.1 [0.8] s), 2MWT (164.8 [37.6] m vs 222.6 [26.8] m), and Dizziness Handicap Inventory score (35.4 [20.7] vs 0.1 [0.4]). Conclusions and Relevance: With use of wearable sensors, deficits in head-trunk kinematics were characterized along with a spectrum of disability in individuals in the subacute stage after VS surgery compared with healthy individuals. Future research is needed to fully understand how patterns of exposure to head-on-trunk movements influence the trajectory of recovery of head-trunk coordination during community mobility.

Relationship of hearing loss and dementia: a prospective, population-based study.

OBJECTIVE: To determine whether baseline hearing loss increases cognitive decline and risk for all-cause dementia in a population of elderly individuals. STUDY DESIGN: Longitudinal cohort study. SETTING: Community-based, outpatient. PATIENTS: Men and women aged 65 years or older without dementia at baseline. INTERVENTION(S): All subjects completed the Modified Mini-Mental Status Exam (3MS-R) at baseline and over 3 triennial follow-up visits. Hearing loss (HL) at baseline was based on observation of hearing difficulties during testing or interview. Incident dementia was determined by clinical assessment and expert consensus. MAIN OUTCOME MEASURE(S): Dementia and 3MS-R score. RESULTS: At baseline, 4,463 subjects were without dementia, 836 of whom had HL. Of those with HL, 16.3% developed dementia, compared with 12.1% of those without HL (p < 0.001). Mean time to dementia was 10.3 years in the HL group versus 11.9 years for non-HL (log rank test p < 0.001). In Cox regression analyses controlling for sex, presence of APOE- [Latin Small Letter Open E]4 allele, education, and baseline age, and cardiovascular risk factors, HL was an independent predictor of developing dementia (hazard ratio = 1.27, p = 0.026 [95% CI, 1.03-1.56]). Linear mixed models controlling for similar covariates showed HL was associated with faster decline on the 3MS-R, at a rate of 0.26 points/year worse than those without HL. CONCLUSION: Elderly individuals with HL have an increased rate of developing dementia and more rapid decline on 3MS-R scores than their nonhearing impaired counterparts. These findings suggest that hearing impairment may be a marker for cognitive dysfunction in adults age 65 years and older.

Recurrent contralateral hearing loss after 2 craniotomies for vestibular schwannoma: etiologic implications.

OBJECTIVE: To describe recurrent sudden sensorineural hearing loss after contralateral vestibular schwannoma resection and re-resection. STUDY DESIGN: Clinical capsule report. SETTING: Tertiary academic referral hospital. PATIENT: A patient who underwent 2 craniotomies for vestibular schwannoma. RESULTS: In 2003, a patient experienced contralateral low-frequency sensorineural hearing loss after undergoing translabyrinthine resection of a vestibular schwannoma. This resolved after a course of oral steroids. Seven years later, in 2010, the patient developed tumor recurrence. After retrosigmoid resection, the patient experienced a similar episode of transient, contralateral, low-frequency predominant sensorineural hearing loss. CONCLUSION: The recurrence of contralateral hearing loss after craniotomies years apart suggests that patient specific anatomic risk factors predispose an individual to hearing loss after contralateral cerebellopontine angle surgery. Patients with previous history of contralateral hearing loss should be counseled that they may be at increased risk for recurrent loss in the setting of re-resection.