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KEY POINTS: Sensory systems are adapted to the statistical structure of natural stimuli, thereby optimizing neural coding. Head motion during natural activities is first sensed and then processed by central vestibulo-motor pathways to influence subsequent behaviour, thereby establishing a feedback loop. To investigate the role of this vestibular feedback on the statistical structure of the head movements, we compared head movements in patients with unilateral vestibular loss and healthy controls. We show that the loss of vestibular feedback substantially alters the statistical structure of head motion for activities that require rapid online feedback control and predict this change by modelling the effects of increased movement variability. Our findings suggest that, following peripheral vestibular loss, changes in the reliability of the sensory input to central pathways impact the statistical structure of head motion during voluntary behaviours. ABSTRACT: It is widely believed that sensory systems are adapted to optimize neural coding of their natural stimuli. Recent evidence suggests that this is the case for the vestibular system, which senses head movement and contributes to essential functions ranging from the most automatic reflexes to voluntary motor control. During everyday behaviours, head motion is sensed by the vestibular system. In turn, this sensory feedback influences subsequent behaviour, raising the questions of whether and how real-time feedback provided by the vestibular system alters the statistical structure of head movements. We predicted that a reduction in vestibular feedback would alter head movement statistics, particularly for tasks reliant on rapid vestibular feedback. To test this proposal, we recorded six-dimensional head motion in patients with variable degrees of unilateral vestibular loss during standard balance and gait tasks, as well as dynamic self-paced activities. While distributions of linear accelerations and rotational velocities were comparable for patients and age-matched healthy controls, comparison of power spectra revealed significant differences during more dynamic and challenging activities. Specifically, consistent with our prediction, head movement power spectra were significantly altered in patients during two tasks that required rapid online vestibular feedback: active repetitive jumping and walking on foam. Using computational methods, we analysed concurrently measured torso motion and identified increases in head-torso movement variability. Taken together, our results demonstrate that vestibular loss significantly alters head movement statistics and further suggest that increased variability and impaired feedback to internal models required for accurate motor control contribute to the observed changes.

BackgroundThis paper describes a protocol for determining the incidence of serious fall injuries for Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE), a large, multicenter pragmatic clinical trial with limited resources for event adjudication. We describe how administrative data (from participating health systems and Medicare claims) can be used to confirm participant-reported events, with more time- and resource-intensive full-text medical record data used only on an "as-needed" basis.MethodsSTRIDE is a pragmatic cluster-randomized controlled trial involving 5451 participants age ≥ 70 and at increased risk for falls, served by 86 primary care practices in 10 US health systems. The STRIDE intervention involves a nurse falls care manager who assesses a participant's underlying risks for falls, suggests interventions using motivational interviewing, and then creates, implements and longitudinally follows up on an individualized care plan with the participant (and caregiver when appropriate), in partnership with the participant's primary care provider. STRIDE's primary outcome is serious fall injuries, defined as a fall resulting in: (1) medical attention billable according to Medicare guidelines with a) fracture (excluding isolated thoracic vertebral and/or lumbar vertebral fracture), b) joint dislocation, or c) cut requiring closure; OR (2) overnight hospitalization with a) head injury, b) sprain or strain, c) bruising or swelling, or d) other injury determined to be "serious" (i.e., burn, rhabdomyolysis, or internal injury). Two sources of data are required to confirm a serious fall injury. The primary data source is the participant's self-report of a fall leading to medical attention, identified during telephone interview every 4 months, with the confirmatory source being (1) administrative data capturing encounters at the participating health systems or Medicare claims and/or (2) the full text of medical records requested only as needed.DiscussionAdjudication is ongoing, with over 1000 potentially qualifying events adjudicated to date. Administrative data can be successfully used for adjudication, as part of a hybrid approach that retrieves full-text medical records only when needed. With the continued refinement and availability of administrative data sources, future studies may be able to use administrative data completely in lieu of medical record review to maximize the quality of adjudication with finite resources.Trial registrationClinicalTrials.gov (NCT02475850).

Introduction: Spatial navigation, the ability to move through one's environment, is a complex skill utilized in everyday life. The effects of specific vestibular end-organ deficits and hearing impairments on spatial navigation have received little to no attention. We hypothesized that hearing impairment adversely affects spatial navigation and that bimodal impairments (vestibular and hearing) further impair navigation ability. Methods: Data from 182 participants in the Baltimore Longitudinal Study of Aging who had interpretable results for the video head impulse test (vHIT), cervical vestibular evoked myogenic potentials (cVEMP) and ocular vestibular evoked myogenic potentials (oVEMP), audiometric testing, and the triangle completion test (TCT) were retrospectively analyzed. Multiple linear regression, controlling for age, sex, and cognition, was employed to identify predictors of TCT performance in terms of end-point error, angle deviation, and distance walked. Results: oVEMP abnormalities were associated with larger end-point error (p = 0.008) and larger angle deviation (p = 0.002) but were not associated with distance walked (p = 0.392). Abnormalities on cVEMP testing and vHIT were not associated with distance walked (p = 0.835, p = 0.300), end-point error (p = 0.256, p = 0.808), or angle deviation (p = 0.192, p = 0.966). Compared with normal-hearing adults, hearing-impaired adults walked a shorter distance during the TCT (p = 0.049) but had a similar end-point error (p = 0.302) and angle deviation (p = 0.466). There was no interaction between vestibular and hearing function for predicting spatial navigation ability. Conclusion: In this cohort analysis, utricular dysfunction and hearing impairment were associated with poorer spatial navigation performance. We postulate that hearing impairment negatively affects one's ability to use real-time, intrinsic auditory cues and/or prior experience to guide navigation. Plain Language Summary: Spatial navigation, the ability to move through one's environment, is a complex skill utilized in everyday life. The effects of specific balance and hearing deficits on spatial navigation have not been extensively studied. Thus, we analyzed data from 182 participants in the Baltimore Longitudinal Study of Aging who completed balance, hearing, and spatial navigation tests to determine if hearing impairment may adversely affect spatial navigation and if combined deficits in balance and hearing further impair navigation ability. Our analyses accounted for the confounding effects of age, sex, and cognition on aspects of spatial navigation performance. We found that deficits in hearing and in the balance organ that senses horizontal translational movements were associated with worse performance on spatial navigation. However, deficits in the balance organs that sense vertical translational movements and horizontal rotational movements were not associated with worse spatial navigation ability. Surprisingly, we found that those with combined balance and hearing deficits did not perform significantly worse on spatial navigation than those with deficits in either balance or hearing alone. We believe that the abnormal function of the horizontal translational movement sensors likely explains the gait disorientation experienced by persons with inner ear problems. Additionally, we propose that hearing deficits impede one's ability to use real-time sound cues to guide navigation. Many of our participants had mild deficits; thus, further research on the effects of more severe balance and hearing deficits on spatial navigation is needed to gain a better understanding of how different sensory inputs contribute to spatial navigation ability. [ABSTRACT FROM AUTHOR]

ObjectiveTo determine postoperative hearing outcomes after surgical plugging via middle cranial fossa approach for superior semicircular canal dehiscence syndrome (SCDS).Study designClinical review.SettingTertiary care medical center.PatientsForty-three cases of SCDS based on history, physical examination, vestibular function testing, and computed tomography imaging confirming the presence of a dehiscence. All patients underwent surgical plugging of the superior semicircular canal via middle cranial fossa approach.InterventionPure tone audiometry was performed preoperatively and at 7 days and at least 1 month postoperatively.Main outcome measuresChange in air-bone gap (ABG) and pure tone average (PTA).ResultsPreoperative average ABG across 0.25, 0.5, 1, and 2 kHz was 16.0 dB (standard deviation [SD], 7.5 dB). At 7 days postoperatively, average ABG was 16.5 dB (SD, 11.1; p = 0.42), and at greater than 1 month was 8.1 dB (SD, 8.4; p < 0.001). 53% (95% confidence interval, 33-69) of affected ears had greater than 10 dB increase in their 4-frequency (0.5, 1, 2, and 4 kHz) PTA measured by bone-conduction (BC) threshold 7 days postoperatively and 25% (95% confidence interval, 8-39) at greater than 1 month postoperatively. Mean BC PTA of affected ears was 8.4 dB hearing loss (HL) (SD, 10.4) preoperatively. Compared with baseline, this declined to 19.2 dB HL (SD, 12.6; p < 0.001) at 7 days postoperatively and 16.4 dB HL (SD, 18.8; p = 0.01) at greater than 1 month. No significant differences in speech discrimination score were noted (F = 0.17).ConclusionLow-frequency air-bone gap decreases after surgical plugging and seems to be due to both increased BC thresholds and decreased AC thresholds. Surgical plugging via a middle cranial fossa approach in SCDS is associated with mild high-frequency sensorineural hearing loss that persists in 25% but no change in speech discrimination.

Background Poor motor function is associated with brain atrophy and cognitive impairment. Less is known about the relationship between motor domains and brain atrophy and whether associations are affected by cerebrovascular burden and/or physical activity. Methods We analyzed data from 726 Baltimore Longitudinal Study of Aging participants (mean age 70.6 ± 10.1 years, 56% women, 27% Black), 525 of whom had repeat MRI scans over an average of 5.0 ± 2.1 years. Two motor domains, manual dexterity and gross motor, were operationalized as latent variables. Associations between the latent variables and cortical and subcortical brain volumes of interest were examined using latent growth curve modeling, adjusted for demographics, white matter hyperintensities, and physical activity. Results Both higher manual dexterity and gross motor function were cross-sectionally associated with smaller ventricular volume and greater white matter volumes in the frontal, parietal, and temporal lobes (all p  < .05). Manual dexterity was also cross-sectionally associated with parietal gray matter (B  = 0.14; 95% CI: 0.05, 0.23), hippocampus (B  = 0.10; 95% CI: 0.01, 0.20), postcentral gyrus (B  = 0.11; 95% CI: 0.01, 0.20), and occipital white matter (B  = 0.10; 95% CI: 0.01, 0.21) volumes, and gross motor function with temporal gray matter volume (B  = 0.16; 95% CI: 0.05, 0.26). Longitudinally, both higher manual dexterity and gross motor function were associated with less temporal white matter and occipital gray matter atrophy (all p  < .05). Manual dexterity was also associated with a slower rate of ventricular enlargement (B  = −0.17; 95% CI: −0.29, −0.05) and less atrophy of occipital white matter (B  = 0.39; 95% CI: 0.04, 0.71). Conclusions Among cognitively normal middle- and older-aged adults, manual dexterity and gross motor function exhibited shared as well as distinct associations with brain atrophy over time. [ABSTRACT FROM AUTHOR]

Due to the long prodromal period for dementia pathology, approaches are needed to detect cases before clinically recognizable symptoms are apparent, by which time it is likely too late to intervene. This study contrasted two theoretically-based algorithms for classifying early cognitive impairment (ECI) in adults aged ≥50 enrolled in the Baltimore Longitudinal Study of Aging. Two ECI algorithms were defined as poor performance (1 standard deviation [SD] below age-, sex-, race-, and education-specific means) in: (1) Card Rotations or California Verbal Learning Test (CVLT) immediate recall and (2) ≥1 (out of 2) memory or ≥3 (out of 6) non-memory tests. We evaluated concurrent criterion validity against consensus diagnoses of mild cognitive impairment (MCI) or dementia and global cognitive scores using receiver operating characteristic (ROC) curve analysis. Predictive criterion validity was evaluated using Cox proportional hazards models to examine the associations between algorithmic status and future adjudicated MCI/dementia. Among 1,851 participants (mean age = 65.2 ± 11.8 years, 50% women, 74% white), the two ECI algorithms yielded comparably moderate concurrent criterion validity with adjudicated MCI/dementia. For predictive criterion validity, the algorithm based on impairment in Card Rotations or CVLT immediate recall was the better predictor of MCI/dementia (HR = 3.53, 95%CI: 1.59–7.84) over 12.3 follow-up years. Impairment in visuospatial ability or memory may be capable of detecting early cognitive changes in the preclinical phase among cognitively normal individuals. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to characterize the associations of sensory impairments, including olfaction (OI), vision (VI), hearing (HI), and touch (TI), with telomere length (TL) in a group of community‐dwelling older adults who participated in the Health ABC study. Methods: Across 1603 participants, OI was classified with the Brief Smell Identification Test (<11), HI with pure‐tone averages (<25 dB), VI with visual acuity (20/50 or worse), and TI with monofilament testing (inability to detect three of four touches). Shorter TL was defined as the lowest quartile of sample TLs. Adjusted multivariable regressions were used to examine the cross‐sectional association between the modality, severity, and number of sensory impairments with TL. Results: Participants had an average age of 77.4 ± 2.84 years, and 89.7% (n = 1438) had at least one or more sensory impairments. Severe OI (odds ratio [OR] = 1.73, 95% confidence interval [CI] = [1.19, 2.6]) was independently associated with increased odds of shorter TL. Additionally, having one (OR = 2.79, 95% CI = [1.69, 4.70]), two (OR = 2.5, 95% CI = [1.51, 4.26]), three (OR = 3.04, 95% CI = [1.79, 5.36]), or four impairments (OR = 3.72, 95% CI = [1.52, 7.33]) was associated with increased odds of shorter TL in a dose‐dependent manner. Conclusion: Severe OI and TI appear to be particularly robust markers of shortened TL. Additionally, multiple sensory impairment is strongly associated with shortened TL, suggesting that sensory dysfunction may represent a unique biomarker of unhealthy aging. Level of Evidence: Level II Laryngoscope, 133:3132–3138, 2023 [ABSTRACT FROM AUTHOR]