Cognition Effects of Hearing Aids and Auditory Training in Older Age
Condition: Hearing Loss, Sensorineural
MeSH terms: Hearing Loss; Deafness; Hearing Loss, Sensorineural
Study type: Interventional

Summary: 
      Sensorineural type of hearing loss is the most common sensory deficit among older adults.
      Some of the psychosocial consequences of this condition include difficulty in understanding
      speech, depression and social isolation. Studies have shown that older adults with hearing
      loss show some age-related cognitive decline. There is no clinically proven method to predict
      the onset of this condition, as its occurrence is slow and progressive, affecting both ears
      equally. Although hearing aid use and auditory training have been proven as successful
      interventions to alleviate sensorineural hearing loss, no research has been designed to look
      at the effect of both hearing aid use coupled with auditory training on cognitive performance
      in older adults. This study will investigate whether wearing hearing aids will improve the
      impact of auditory training on cognition, mood and social interaction for older adults with
      sensorineural hearing loss.

      This is a crossover trial targeting older adults between 50 and 90 years with either mild or
      moderate symmetric sensorineural hearing loss. Consented, willing participants will undergo a
      six month intensive auditory training program (active control), as a rigorous means of
      examining the impact hearing aid use has on a person's cognition, mood and social
      interaction. Participants will be assigned in random order to receive hearing aid
      (intervention) for either the first three or last three months of the six month auditory
      training program. Each participant will be tested at baseline, three and six months on a
      battery of computer based cognitive assessments, together with mood, and social engagement
      measures. Effectiveness of hearing aids and auditory training will be evaluated using an
      online speech perception test (SPT) and the Abbreviated Profile of Hearing Aid Benefit
      (APHAB) Inventory.

      This study will investigate whether using a hearing aid coupled with auditory training can
      improve a person's cognition and learning abilities, relationships with family and friends,
      and quality of life. Results from the study will inform strategies for aural rehabilitation,
      hearing aid delivery and future hearing loss intervention trials.
    

Detailed description: 
      Background:

      Sensorineural hearing loss is the most common sensory deficit among older adults. There is no
      clinically proven method to predict the onset of this condition, as its occurrence is
      generally slow and progressive, affecting both ears equally. Recent studies have documented
      that hearing loss in older adults is independently associated with reduced cognitive
      functioning, mood and social interaction, and that hearing aid use and auditory training
      could improve cognitive abilities, social, emotional, psychological, and physical well-being
      of people. Despite the high prevalence of hearing loss in older adults, and the consequences
      for health outcomes, people are generally slow to acquire hearing aids, and almost two-thirds
      of older adults with hearing impairment do not use hearing aids. The popularity of auditory
      training has also declined in recent years and the focus of research has been shifted to only
      improving wearable amplification such as hearing aids. No research has been designed to
      specifically look at the effect of both hearing aid use coupled with auditory training on
      cognitive performance in older adults.

      Study aim:

      The aim of the current study is to investigate the impact of hearing aid use coupled with
      auditory training on mood, social relationships and cognitive functioning in a crossover
      intervention trial.

      Study hypothesis:

      The rationale for this study objective is based on the following hypotheses:

      H1: In older adults with sensorineural hearing loss, hearing aids in combination with
      auditory training will be more effective for improving cognition than auditory training on
      its own.

      H2: In older adults with sensorineural hearing loss, hearing aids in combination with
      auditory training will be more effective for improving mood and social interaction than
      auditory training on its own.

      Crossover design:

      This is a randomised crossover trial with a total of 40 participants randomized into two
      equal groups (20 each) to carry out separate crossover experiments. All participants will
      undergo individualised auditory training for a period of 6 months, and will be randomly
      allocated to one of the following groups.

        1. Participants who will be fitted with hearing aids only for the first 3 months of the
           auditory training program - Group A

        2. Participants who will be fitted with hearing aids only for the last 3 months of the
           auditory training program - Group B Participants will be tested at baseline, and at
           three and six months in terms of cognition, mood and social engagement. The primary
           outcome measure will be changes in cognitive performance as measured by the Swinburne
           University Computerized Assessment Battery (SUCCAB). Secondary outcome measures will
           include changes in mood and social engagement scores.

      Setting of the study This study is set in Victoria, Australia. It will be conducted in
      independent living aged care facilities across Melbourne. These residents live in their own
      unit or similar accommodation, and are generally capable of caring for themselves in all
      aspects of daily living. In addition, elderly participants from the Swinburne University of
      Technology's Centre for Human Psychopharmacology (CHP) database who live independently will
      be recruited to take part in the study.

      Recruitment:

      Independent living aged care facilities will be contacted by telephone to explain the study.
      If an aged care facility shows interest in the study, researchers will visit the facility to
      provide the facility manager with more detailed written and oral information. If the facility
      manager consents for their facility to participate in the study, the study will be advertised
      at the facility and flyers will be distributed to all the residents inviting them to an
      information session. Participants from the Swinburne University of Technology's CHP database
      will be contacted by telephone and email to explain the study and participants who express
      interest will be invited to attend an information session. At the information session,
      researchers will explain the purpose and significance of the study. At the same time, a
      pre-selection screening will be conducted to identify participants who are cognitively
      healthy, likely to benefit from hearing rehabilitation, and who will be able to participate
      in the cognition battery testing (reasonable sight and not colour blind). Selected
      participants will be sent a Participant Information and Consent Form package that includes
      detailed information on the study procedure, a consent form and a return pre-paid envelope.
      Once written consent is received, participants will be invited to complete baseline measures
      and to confirm their eligibility before enrolment into the study.

      Participants:

      The baseline cohort will consist of forty (40) older adults with either a mild or moderate
      symmetric sensorineural hearing loss. All participants will be first time hearing aid users,
      having never worn hearing aids previously. Participants will be screened for adequate
      cognitive functioning using the Mini-mental state examination (MMSE). Participants must have
      a global cognitive impairment as determined by a score greater than 24 on the (MMSE).

      Sample size:

      Power analyses were conducted to determine the sample size required. Previous research and
      the results of the power analysis suggest that a total sample size of 36 is sufficient to
      detect a moderate size effect (f=0.25), with power of 80% and a significance level of 5%.
      Therefore, a total sample size of 40 participants will be recruited to provide a definitive
      test of the hypotheses, while allowing for 10% attrition.

      Data collection methods:

      The assessments selected for this study are categorized as:

        1. Hearing Assessments

             -  Otoscopy and tympanometry: Following otoscopy, all participants will undergo
                tympanometry and acoustic reflex testing to assess the status of the middle ear.

             -  Pure tone audiometry in each ear: To understand the degree of hearing impairment,
                hearing ability will be measured at threshold frequencies 0.5, 1, 2, 3, 4, 6 kHz in
                both ears. An online Speech Perception Test will be used in addition to the
                standard audiograms for the purpose of measuring hearing loss and hearing aid
                fitting.

        2. Paper-based Questionnaire

      Participants will complete a paper-based questionnaire which will be structured in the
      following sections:

        -  Demographics: Information on a variety of demographic variables will be collected in
           order to describe the characteristics of the study participants

        -  The Geriatric Depression Scale (GDS): To assess mood, the short version of the GDS will
           be used to detect the depressive symptoms in the elderly.

        -  Social Engagement Measure: The Berkman-Syme Social Network Index will be used to measure
           participants' social engagement and connections with families, friends, etc.

        -  The Mini-Mental State Examination (MMSE) Questionnaire: The MMSE will be used as a
           screening criterion to assess cognition.

           3. Cognitive Assessments

        -  The Swinburne University Computerized Assessment Battery (SUCCAB) will be used as a
           primary measure to assess cognitive performance. Reliability and validity testing of
           this battery has demonstrated that the SUCCAB is sensitive to ageing, and has been shown
           to be particularly effective for measuring short-term changes in cognition for the
           elderly. The SUCCAB correlates strongly with memory subsets in the Wechsler Adult
           Intelligence Scales.

      All participants who will be enrolled into the study will complete these assessments again at
      3 months and at 6 months.

      Interventions:

      Fitting of hearing aids for Group A and Group B participants:

      Participants will be fitted with two Blamey Saunders hearing aids known as the LOF for a
      period of 3 months. The hearing aids will be fitted according to the manufacturer's protocol,
      and explanation of the hearing aid usage, insertion of the aids and batteries along with a
      step-by-step guide on how to use the hearing aid will be given. A data logging function in
      the hearing aids will be used to assess hours of hearing aid use.

      After 3 months (with wearing their hearing aids)

      In addition, the Abbreviated Profile of Hearing Aid Benefit (APHAB), a self-assessment
      inventory, will be carried out with the assistance of the researcher to assess hearing aid
      benefit. Four scales of the APHAB will be assessed namely:

        -  Ease of communication (EC)

        -  Effects of background noise (BN)

        -  Effects of reverberation (RV), such as listening to sounds across a large room
           Aversiveness (AV), which will look at uncomfortable loudness of background sounds such
           as traffic and alarm bells.

      Auditory training:

      All participants enrolled into the study will undergo weekly auditory training for a period
      of 6 months. Over the 6 month period, each participant will undergo a two 12-week
      individualised speech tracking program, called the Continuous Discourse Speech Tracking, with
      and without hearing aids. Each test session will last for approximately 15 minutes. The
      procedure will be timed and scored in number of words per minute (wpm) transmitted. Tracking
      rate will be calculated as the number of words correctly repeated divided by the time
      elapsed.

      Working Alliance Inventory:

      At the end of the 6 month period after all examinations have been completed, Group A and B
      participants will complete a working alliance inventory, in order to evaluate the following:
      the quality of participant-researcher relationship, the collaborative nature of agreeing on
      tasks and goals of both auditory training and hearing aid compliance, and the outcome
      measures from auditory training provided to participants. Some randomized controlled trials
      have demonstrated that this evaluation is crucial for engaging, retaining and improving
      positive outcomes for study participants, and is vital for relationship-building.

      Planned analysis

        -  Baseline comparison of the two groups in terms of demographics, cognition, mood, social
           engagement, hearing loss and hearing satisfaction using appropriate chi-square test,
           t-test and non-parametric Mann-Whitney tests.

        -  Comparison of the two groups in terms of changes in cognition, mood, social engagement
           from baseline to 3 months and 6 months, using a crossover analysis and multi-level
           models, allowing for any carry-over effect.

        -  The analysis of speech perception test results with and without hearing aids as a
           measure of the effectiveness of hearing aids and auditory training with and without
           hearing aids using multi-level models and again allowing for carry-over effects.

        -  The speech tracking rates from the two 12-week programs of speech tracking will be
           analysed for each participant using a learning model. This analysis will yield learning
           and forgetting rates with and without hearing aids. These learning and forgetting rates
           are valid measures of cognitive processes that are likely to be affected by the use of
           hearing and hearing aids. This data will also be analysed using multi-level models and
           again allowing for carry-over effects.

      Contingency Plan: For participants who decide to discontinue auditory training because
      hearing aids have been beneficial, or decide to drop out entirely in the course of the
      auditory training program, they will be retained in the study as a third group, with a
      suitable modification to the analysis.
    

Intervention name(s): Hearing aid; Auditory Training
Intervention type(s): Device; Behavioral
Intervention description(s): LOF hearing aid
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This is a randomised crossover trial with participants randomized into two equal groups to carry out separate crossover experiments. All participants will undergo an individualised auditory training for a period of 6 months, and will be randomly allocated to one of the following groups.
Participants who will be fitted with hearing aids for the first 3 months of auditory training program - Group A
Participants who will be fitted with hearing aids for the last 3 months of auditory training program - Group B Groups will be matched in terms of the degree of hearing loss with one member from each matched pair randomly assigned to Group A and the other member of each matched pair assigned to Group B. A random sequence of binary digits will be used for this purpose.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Crossover design; Randomized controlled trial; Aural rehabilitation intervention