Head movement and its relation to hearing.

Head position at any point in time plays a fundamental role in shaping the auditory information that reaches a listener, information that continuously changes as the head moves and reorients to different listening situations. The connection between hearing science and the kinesthetics of head movement has gained interest due to technological advances that have increased the feasibility of providing behavioral and biological feedback to assistive listening devices that can interpret movement patterns that reflect listening intent. Increasing evidence also shows that the negative impact of hearing deficits on mobility, gait, and balance may be mitigated by prosthetic hearing device intervention. Better understanding of the relationships between head movement, full body kinetics, and hearing health, should lead to improved signal processing strategies across a range of assistive and augmented hearing devices. The purpose of this review is to introduce the wider hearing community to the kinesiology of head movement and to place it in the context of hearing and communication with the goal of expanding the field of ecologically-specific listener behavior.

Hearing and Mobility in Aging-The Moderating Role of Neuropsychological Function.

BACKGROUND: In older persons, neuropsychological function, especially sensorimotor function, is strongly associated with mobility. Hearing impairment is related to poor mobility, and we hypothesize that such relationships would be stronger in persons with compromised sensorimotor function than those with preserved sensorimotor function. METHODS: We analyzed 601 cognitively normal (Mini-Mental State Examination ≥24 or free of cognitive impairment/dementia) Baltimore Longitudinal Study of Aging participants aged 50 or older with concurrent data on hearing (better ear pure-tone average [PTA]), mobility (6 m usual gait, 400 m endurance walk), and neuropsychological function including attention via Trail Making Test (TMT)-A, executive function via the difference between TMT-A and B, and Digit Symbol Substitution Test, and manual dexterity via Pegboard performance. We examined the association of PTA, each cognitive measure, and their interaction with mobility using multivariable linear regression, adjusted for covariates. RESULTS: After covariate adjustment, there were significant interactions between PTA and all cognitive measures in the association with 400 m endurance walking speed as the outcome. There was also a significant interaction between PTA and pegboard nondominant hand performance in the association with 6 m gait as the outcome. In all these cases, the PTA-mobility relationship was stronger among participants with lower cognition. CONCLUSION: Impaired hearing more strongly relates to poor mobility among those with compromised neuropsychological performance, especially manual dexterity reflecting the motor-cognitive interface and sensorimotor function, than those with preserved neuropsychological performance. Future longitudinal studies are needed to test whether hearing impairment more strongly predicts mobility decline over time in older persons with compromised neuropsychological function.

Reliability of a Novel Video-Based Method for Assessing Age-Related Changes in Upper Limb Kinematics.

Monitoring age-related changes in motor function can be used to identify deviations that represent underlying diseases for which early diagnosis is often paramount for efficacious, interventional therapies. Currently, the availability of cost-effective and reliable diagnostic tools capable of routine monitoring is limited. Adequate diagnostic systems are needed to identify, monitor and distinguish early subclinical symptoms of neurological diseases from normal aging-associated changes. Herein, we describe the development, initial validation and reliability of the Hand-Arm Movement Monitoring System (HAMMS), a video-based data acquisition system built using a programmable, versatile platform for acquiring temporal and spatial metrics of hand and arm movements. A healthy aging population of 111 adults were used to evaluate the HAMMS via a repetitive motion test of changing target size. The test required participants to move a fiducial on their hand between two targets presented on a video monitor. The test-retest reliability based on Intraclass Correlation Coefficient (ICCs) for the system ranged from 0.56 to 0.87 and the Linear Correlation Coefficients (LCCs) ranged from 0.58 to 0.87. Average speed, average acceleration, speed error and center offset all demonstrated a positive correlation with age. Using an intertarget path of hand motion, we observed an age-dependent increase in the average number of points outside the most direct motion path, indicating a reduction in hand-arm movement control with age. The reliability, flexibility and programmability of the HAMMS makes this low cost, video-based platform an effective tool for evaluating longitudinal changes in hand-arm related movements and a potential diagnostic device for neurological diseases where hand-arm movements are affected.