One in six people in the United Kingdom and over 400 million people worldwide have disabling hearing loss. This figure will double by 2050 as predicted by the World Health Organisation. There is an urgent need to improve our knowledge regarding hearing loss, its underlying mechanisms, optimal diagnostic modalities, reliable and accurate functional and imaging biomarkers. A less-well studied condition associated with progressive hearing loss is infratentorial superficial siderosis (iSS). It results from iron deposition along the surfaces of brain structures which control hearing and balance. It is currently considered uncommon, but may well be under-recognised and therefore under-reported. Despite its severity, our current understanding of its impact on the hearing (auditory) and balance (vestibular) functions is limited, and this has an adverse impact on the treatment offered to these patients. Additionally, iSS patients have been reported to have cognitive impairment yet literature reports of cognitive assessment in iSS are few. The cognitive dysfunction may be specific to iSS or due to progressive hearing impairment or a combination of both, and further studies are required to establish this. Olfaction is also known to be affected in patients with iSS yet is rarely reported in the literature. Due to the significant morbidity and progressive nature, there is a clear need to improve our understanding of the audiovestibular dysfunction resulting from iSS. The aim of this study is to comprehensively assess audiovestibular function in iSS compared to age-related hearing loss and the controls/normative data and as a means to quantify deficits for monitoring disease progression and response to treatment, to assess the impact on the quality of life, to analyse clinically-obtained data (including imaging, cognitive and laboratory data), and correlate these with functional findings in iSS.
This study focuses on a rare condition called infratentorial superficial siderosis (iSS)-a disease where iron gradually accumulates in the superficial layers of the brain and spinal cord. Over time, this buildup can damage the nerves responsible for hearing and balance amongst others, leading to symptoms like progressive hearing loss, dizziness, and problems with coordination. iSS has not been well studied in the past. The hearing and balance function in persons with iSS has been described as variable - meaning, there has not been a specific pattern of hearing loss or imbalance or dizziness that can be associated with iSS. The studies to date have been with small groups of patients but mainly case reports. The aim of the AVISS study has been to address this gap in the knowledge. This study investigates how iSS affects hearing, balance, and even sense of smell by studying three groups of people: 1. People with iSS, who already have hearing and balance problems. 2. People with age-related hearing loss, to compare how hearing declines over time. 3. People with normal hearing, serving as a control group. The study will take place over three years, using a range of tests to assess hearing and balance: * Hearing tests like pure tone audiometry, speech-in-noise assessments, and auditory brainstem response. * Balance tests such as vestibular evaluations, gait assessments, and head impulse testing. * Olfactory (smell) tests, since iSS might also affect sensory perception. By collecting this data, the study aims to improve how iSS is diagnosed, identify better rehabilitation methods, and explore new treatment options for those affected. The study is funded by NIHR UCLH Biomedical Research Centre and the Bernice Bibby Research Trust, ensuring experts have the resources needed to make meaningful discoveries. Ultimately, the goal is to help doctors recognize iSS earlier, support affected individuals more effectively and improve their overall quality of life.
Study Type
OBSERVATIONAL
Enrollment
11
All study participants will undergo hearing tests, including hearing-specific questionnaires
Siderosis group participants will undergo vestibular/balance tests, including gait assessment and balance-specific questionnaires
All study participants will be asked to complete a set of quality of life questionnaires
Siderosis group participants will undergo a formal smell identification testing by means of self-administered smell chart to identify the revealed scents
Siderosis group participants will be asked to provide a saliva sample for DNA bio-banking
UCL Ear Institute
London, United Kingdom
University College London Hospitals NHS Foundation Trust
London, United Kingdom
Hearing Evaluation - Pure Tone Audiometry
Clinical audiological (hearing) tests were performed to assess hearing function. The hearing tests included psychophysical, physiological and electrophysiological measures, (pure-tone audiometry, tympanometry, auditory brainstem responses and acoustic reflexes). The tests were perfomed in line with the procedure guidelines by the British Society of Audiology (www.thebsa.org.uk). The mean value of pure-tone audiometric thresholds for both ears measured in decibel hearing level (as described in the guidelines by the British Society of Audiology) was calculated and reported. Other parameters were reported as normal or abnormal (in at least one ear) or inconclusive.
Time frame: Baseline visit
Vestibular/Balance Evaluation
Clinical vestibular and balance tests were performed to assess vestibular/balance function.
Time frame: Baseline visit
Hearing Evaluation - Auditory Brainstem Responses/Acoustic Reflexes
Clinical audiological (hearing) tests were performed to assess hearing function. The hearing tests included psychophysical, physiological and electrophysiological measures, (pure-tone audiometry, tympanometry, auditory brainstem responses and acoustic reflexes). The tests were perfomed in line with the procedure guidelines by the British Society of Audiology (www.thebsa.org.uk). The mean value of pure-tone audiometric thresholds for both ears measured in decibel hearing level (as described in the guidelines by the British Society of Audiology) was calculated and reported. Other parameters were reported as normal or abnormal (in at least one ear) or inconclusive.
Time frame: Baseline visit
Hearing Evaluation - Tympanogram
Clinical audiological (hearing) tests were performed to assess hearing function. The hearing tests included psychophysical, physiological and electrophysiological measures, (pure-tone audiometry, tympanometry, auditory brainstem responses and acoustic reflexes). The tests were perfomed in line with the procedure guidelines by the British Society of Audiology (www.thebsa.org.uk). The mean value of pure-tone audiometric thresholds for both ears measured in decibel hearing level (as described in the guidelines by the British Society of Audiology) was calculated and reported. Other parameters were reported as normal or abnormal (in at least one ear) or inconclusive.
Time frame: Baseline
Hearing Evaluation - Otoacoustic Emissions
Clinical audiological (hearing) tests were performed to assess hearing function. The hearing tests included psychophysical, physiological and electrophysiological measures, (pure-tone audiometry, tympanometry, auditory brainstem responses and acoustic reflexes). The tests were perfomed in line with the procedure guidelines by the British Society of Audiology (www.thebsa.org.uk). The mean value of pure-tone audiometric thresholds for both ears measured in decibel hearing level (as described in the guidelines by the British Society of Audiology) was calculated and reported. Other parameters were reported as normal or abnormal (in at least one ear) or inconclusive.
Time frame: Baseline
Hearing Evaluation - Listening in Spatialised Sentences Noise Test
Clinical audiological (hearing) tests were performed to assess hearing function. The hearing tests included psychophysical, physiological and electrophysiological measures, (pure-tone audiometry, tympanometry, auditory brainstem responses and acoustic reflexes). The tests were perfomed in line with the procedure guidelines by the British Society of Audiology (www.thebsa.org.uk). The mean value of pure-tone audiometric thresholds for both ears measured in decibel hearing level (as described in the guidelines by the British Society of Audiology) was calculated and reported. Other parameters were reported as normal or abnormal (in at least one ear) or inconclusive. Cameron S, Dillon H. The listening in spatialized noise-sentences test (LISN-S): comparison to the prototype LISN and results from children with either a suspected (central) auditory processing disorder or a confirmed language disorder. J Am Acad Audiol. 2008 May;19(5):377-91.
Time frame: Baseline
Correlation Between Clinically Obtained Imaging (Siderosis Group Participants) and the Hearing and Balance Assessment Results
Siderosis group participants underwent formal imaging procedures as part of their clinical care pathway. The imaging results were reviewed with the results obtained from hearing and vestibular/balance assessments. All participants had MRI Brain, as part of their clinical care pathway; susceptibility-weighted images were reviewed to identify the appearance of superficial siderosis, in keeping with the radiological diagnostic criteria (Reference: Wilson et al, 2017).
Time frame: Baseline visit
Correlation Between Clinically Obtained Results of Cognitive Function Assessment (Siderosis Group Participants) and the Hearing and Balance Assessments
Siderosis group participants underwent a formal neuro-cognitive assessment as part of their clinical care pathway. The results of this clinical assessment were reviewed to determine if an association exists between the cognitive assessment results and the results obtained from hearing and vestibular/balance assessments performed during the study. A formal neuro-cognitive assessment was performed using the Wechsler Adult Intelligence Scale test. Cognitive impairment in a domain was defined as scoring at or below the fifth percentile on any one test in that domain.
Time frame: Baseline visit
Smell Identification Test
University of Pennsylvania Smell Identification Test (UPSIT, British version) was performed (siderosis group participants) to assess their olfactory function. UPSIT is a forced-choice 40-item self-administered test. The scores are calculated using manufacturer's answer key as the sum of correct answers (maximum best = 40, minimum score 6; anosmia \<19(males, females); normosmia \>33 (males) and \>34 (females)), and compared to the age- and gender-matched norms. The scores are also grouped into categories (ranging from normosmia to anosmia), with higher scores indicating better olfactory function.
Time frame: Baseline visit
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