Dual-Task Cost in Bilateral Hearing Loss

The specific aims of the research study are:

1. Compare single-task gait parameters between individuals with hearing loss (HL) and age and education matched controls with normal hearing \[normal vs moderate-profound hearing loss (N=23 for each group)\]. For that we will compare the primary outcome measure, gait speed, between the groups while participants are walking at a comfortable speed for 1 minute.
2. Compare cognitive function between individuals with HL and age and education matched controls. For that we will compare the Neurocognitive Index, derived from a cognitive assessment between groups.
3. Compare the effect of a cognitive task while walking on gait parameters between people with HL and age education matched controls with normal hearing. For that we will compare the primary outcome measure, gait speed, between groups while participants are walking at a comfortable speed and counting backwards \[serial subtraction of 3\] for 1 minute.
4. Explore whether cognitive performance (i.e., the Neurocognitive Index) is correlated with Dual task cost (DTC), a deterioration of gait speed while walking and performing concurrent cognitive task \[serial subtraction of 3\]. The formula to calculate this is the following: DTC = 100 X \[(DT - single task)/ single task\].

Procedure and Data Collection:

Participants will be tested at the NYU Physical Therapy department (380 2nd Ave 3rd and 4th floors). Data will be collected by the main researcher who proposes this research work and/or two other lab researchers who are trained to conduct the full protocol. Testing will take between 1.5 to 2 hours and will always start with the cognitive assessment in order to make sure participants will perform at their best and will not be fatigued. All participants will sign an informed consent form. Participates with HL will be tested without hearing aids since recent studies suggest a possible improvement in balance as well as cognition with amplification. Participates will take off their hearing aid at the beginning of testing.

Screening Examination and Descriptive Measures of participants:

The participants will undergo a sensory systems screen including: Early Treatment Diabetic Retinopathy Study (ETDRS) chart confirming normal vision and a 5.07 monofilament screen confirming normal protective sensation at the bottom of their feet. The screening for the vestibular system will include the Dizziness Handicap Inventory (DHI) questionnaire. Screening of the auditory system will be done in participants with HL (as part of their standard care) and for healthy controls who are 60 years of age or older. Participants will also complete the following questionnaires: a demographics and anthropometrics questionnaire, and Activities-Specific Balance Confidence (ABC) to assess balance confidence. To assess the history of falls questions about past falls will be asked. The MoCA will be administered for people with normal hearing, and the HI-MoCA for people with HL in order to assess mild cognitive decline. For people with HL, the Speech, Spatial and Qualities of Hearing Scale (SSQ12), a test assessing function and interference in hearing in daily living, will be conducted. To assess balance and mobility two tests will be conducted: the modified Clinical Test of Sensory Interaction on Balance (mCTSIB) and Time Up and Go Test (TUG). First participants will wear the APDM inertial motion sensors on both feet and waist and will perform the mCTSIB. They will stand with their hands at their sides, feet together and will perform the following sensory conditions for 30 sec: (1) Stand on a firm surface with eyes open, (2) Stand on a firm surface with eyes closed, (3) Stand on a foam with eyes open, and (4) Stand on a foam with eyes closed. Secondly, participants will perform the TUG twice. The best performance in each condition out of the 2 performances will be recorded.

Cognitive Assessment:

Participants will complete a computerized cognitive battery (CNS vital sign; CNSVS) that will include verbal memory, visual memory, Stroop test, shifting attention and 4-part continuous performance (sustained attention and working memory). Moreover, performance on the single cognitive task (serial subtraction in jumps of 3; measuring working memory and executive function) will also be evaluated while sitting (cognitive single task). The numbers will be recorded for offline processing and the outcome will be the number of correct numbers. These tests do not require the ability to hear in order to pass successfully. Also, there is a need for investigation of cognitive domains such as attention, memory, executive function, and cognitive flexibility in people with HL.

Gait Assessment:

The average speed of gait and spatiotemporal gait parameters would be calculated by the APDM, inertial motion units. Participants will walk in their normal speed for 1 minute along a corridor, back and forth, with or without performing a cognitive task (single or DT). The DT condition will include serial subtraction (counting backwards out loud) in jumps of 3 from a random three-digit number. Randomization of numbers will be done using the excel function generating random numbers (Excel RAND function). The numbers will be recorded for offline processing and the outcome will be the number of correct numbers. Each condition will be performed once, and all conditions will be randomized.

Eligibility Criteria:
Inclusion Criteria:

* Adults aged 40 and older with a clinical diagnosis of bilateral symmetrical moderate which is defined as a PTA between 41-55dB HL (0.5-4 kHz) in the better ear.
* Adults aged 40 and older with a clinical diagnosis of bilateral symmetrical moderately-severe which is defined as a PTA between 56-70dB HL (0.5-4 kHz) in the better ear.
* Adults aged 40 and older with a clinical diagnosis of bilateral symmetrical severe which is defined as a PTA between 71-90dB HL (0.5-4 kHz) in the better ear.
* Adults aged 40 and older with a clinical diagnosis of bilateral symmetrical profound which is defined as a PTA above 90+dB HL (0.5-4 kHz) in the better ear.
* No asymmetry of HL which is defined as a difference in PTA that is greater than 15 dB between ears or a difference greater than/equal to 20 dB at two contiguous frequencies or greater than/equal to 10 dB at three contiguous frequencies between ears.
* Adults aged 40 and older with normal hearing which is defined as a PTA below 25dB (0.5-4 kHz) bilaterally.
* Subjects above 65 years of age, with symmetric ARHL in the high frequencies (\>3K), with unaided PTA \< 40 dB (0.5-4KHz) will be included in the control group as well.

Exclusion Criteria:

* A medical diagnosis of peripheral neuropathy.
* Lack of protective sensation based on the Semmes-Weinstein 5.07 Monofilament Test.
* Visual impairment above 20/63 (NYS Department of Motor Vehicle cutoff for driving) on the Early Treatment Diabetic Retinopathy Study (ETDRS) Acuity Test that cannot be corrected with lenses.
* Active complaint of dizziness
* Conductive HL or air bone gap
* A recent onset of a sudden HL
* Pregnancy
* Any neurological condition interfering with balance or walking (e.g. multiple sclerosis, Parkinson's disease, stroke)
* Acute musculoskeletal pain at time of testing
* Currently seeking medical care for another orthopaedic condition or vestibular rehabilitation
* Take medications that might influence gait or balance (e.g., methylphenidate);
* Inability to read an informed consent form in English.