A diagnostic framework to identify vestibular involvement in multi-sensory neurological disease.

BACKGROUND AND PURPOSE: Identifying vestibular causes of dizziness and unsteadiness in multi-sensory neurological disease can be challenging, with problems typically attributed to central or peripheral nerve involvement. Acknowledging vestibular dysfunction as part of the presentation provides an opportunity to access targeted vestibular rehabilitation, for which extensive evidence exists. A diagnostic framework was developed and validated to detect vestibular dysfunction, benign paroxysmal positional vertigo or vestibular migraine. The specificity and sensitivity of the diagnostic framework was tested in patients with primary mitochondrial disease. METHODS: Adults with a confirmed diagnosis of primary mitochondrial disease were consented, between September 2020 and February 2022. Participants with and without dizziness or unsteadiness underwent remote physiotherapy assessment and had in-person detailed neuro-otological assessment. The six framework question responses were compared against objective neuro-otological assessment or medical notes. The output was binary, with sensitivity and specificity calculated. RESULTS: Seventy-four adults completed the study: age range 20-81 years (mean 48 years, ±SD 15.05 years); ratio 2:1 female to male. The framework identified a vestibular diagnosis in 35 participants, with seven having two diagnoses. The framework was able to identify vestibular diagnoses in adults with primary mitochondrial disease, with a moderate (40-59) to very high (90-100) sensitivity and positive predictive value, and moderate to high (60-74) to very high (90-100) specificity and negative predictive value. CONCLUSIONS: Overall, the clinical framework identified common vestibular diagnoses with a moderate to very high specificity and sensitivity. This presents an opportunity for patients to access effective treatment in a timely manner, to reduce falls and improve quality of life.

Auditory processing disorder: an online survey of hearing healthcare professionals' knowledge and practices.

OBJECTIVE: To investigate (1) the current level of awareness and knowledge on Auditory Processing Disorder (APD) among Audiologists and other hearing healthcare professionals; (2) current practices in screening, diagnosis, and management of APD in children and adults across the UK; (3) professional's acceptance of APD assessment and diagnosis. DESIGN: An online survey was disseminated through the British Academy of Audiology and ENT UK. STUDY SAMPLE: A total of 191 hearing healthcare professionals responded to the survey. RESULTS: Overall, while 63% of the respondents considered themselves to be adequately informed about APD, only 4% viewed themselves as very informed on the topic. Fewer than half of the respondents report screening (31%), diagnosing (14%), or managing (36%) cases of APD. For screening APD, professionals most commonly use auditory processing tests in adults and take case histories in children, whereas routine audiological procedures are the primary method for diagnosing APD in both adults and children. Although modifying the listening environment is a widely recommended management strategy for APD, half of the respondents indicated that a diagnosis of APD has no implications for patient management. CONCLUSIONS: There is a critical need to promote APD-related training to ensure they can provide appropriate referrals and management.

Acute truncal ataxia without nystagmus in patients with acute vertigo.

BACKGROUND AND PURPOSE: Differentiating between peripheral and central aetiologies can be challenging in patients with acute vertigo, given substantial symptom overlap. A detailed clinical history and focused physical eye movement examination such as the HINTS eye examination appear to be the most reliable approach to identify acute cerebellar/brainstem stroke, outperforming even acute brain imaging. We have observed, however, that isolated vertigo of central cause may be accompanied by acute truncal ataxia, in the absence of nystagmus. METHODS: We explored the frequency of ataxia without concurrent nystagmus in a cross section of patients with acute vertigo who presented to the emergency department at two centres in Argentina (Group A) and the UK (Group B). Patients underwent detailed clinical neuro-otological assessments (Groups A and B), which included instrumented head impulse testing and oculography (Group B). RESULTS: A total of 71 patients in Group A and 24 patients in Group B were included in this study. We found acute truncal ataxia-without nystagmus-in 15% (n = 14) of our overall cohort. Lesions involved stroke syndromes affecting the posterior inferior cerebellar artery, anterior inferior cerebellar artery, and superior cerebellar artery, thalamic stroke, cerebral hemisphere stroke, multiple sclerosis, and a cerebellar tumour. Additional oculomotor deficits did not reliably identify a central cause in these individuals, even with oculography. CONCLUSIONS: We have identified a significant subpopulation of patients with acute vertigo in whom the current standard approaches such as the HINTS examination that focus on oculomotor assessment may not be applicable, highlighting the need for a formal assessment of gait in this setting.

Auditory Phenotypic Variability in Friedreich's Ataxia Patients.

Auditory neural impairment is a key clinical feature of Friedreich's Ataxia (FRDA). We aimed to characterize the phenotypical spectrum of the auditory impairment in FRDA in order to facilitate early identification and timely management of auditory impairment in FRDA patients and to explore the relationship between the severity of auditory impairment with genetic variables (the expansion size of GAA trinucleotide repeats, GAA1 and GAA2), when controlled for variables such as disease duration, severity of the disease and cognitive status. Twenty-seven patients with genetically confirmed FRDA underwent baseline audiological assessment (pure-tone audiometry, otoacoustic emissions, auditory brainstem response). Twenty of these patients had additional psychophysical auditory processing evaluation including an auditory temporal processing test (gaps in noise test) and a binaural speech perception test that assesses spatial processing (Listening in Spatialized Noise-Sentences Test). Auditory spatial and auditory temporal processing ability were significantly associated with the repeat length of GAA1. Patients with GAA1 greater than 500 repeats had more severe auditory temporal and spatial processing deficits, leading to poorer speech perception. Furthermore, the spatial processing ability was strongly correlated with the Montreal Cognitive Assessment (MoCA) score. To our knowledge, this is the first study to demonstrate an association between genotype and auditory spatial processing phenotype in patients with FRDA. Auditory temporal processing, neural sound conduction, spatial processing and speech perception were more severely affected in patients with GAA1 greater than 500 repeats. The results of our study may indicate that auditory deprivation plays a role in the development of mild cognitive impairment in FRDA patients.

Prevalence of acute dizziness and vertigo in cortical stroke.

BACKGROUND AND PURPOSE: In posterior circulation stroke, vertigo can be a presenting feature. However, whether isolated hemispheric strokes present with vertigo is less clear, despite a few single case reports in the literature. Here, (a) the prevalence of vertigo/dizziness in acute stroke is explored and (b) the cortical distribution of the lesions in relation to both the known vestibular cortex and the evolution of the symptoms, are considered. METHODS: Structured interviews were conducted in 173 consecutive unselected patients admitted to the hyperacute stroke unit at the University College London Hospitals. The interview was used to evaluate whether the patient was suffering from dizziness and/or vertigo before the onset of the stroke and at the time of the stroke (acute dizziness/vertigo), and the nature of these symptoms. RESULTS: In all, 53 patients had cortical infarcts, of which 21 patients reported acute dizziness. Out of these 21, five patients reported rotational vertigo. Seventeen of the total 53 patients had lesions in known vestibular cortical areas distributed within the insular and parietal opercular cortices. CONCLUSIONS: The prevalence of vertigo in acute cortical strokes was 9%, with no single locus of lesion overlap. There is growing evidence supporting a lateralized vestibular cortex, with speculation that cortical strokes affecting the right hemisphere are more likely to cause vestibular symptoms than left hemispheric strokes. A trend was observed for this association, with the right hemisphere affected in four of five patients who reported spinning vertigo at the onset of the stroke.

Peripheral vestibular dysfunction is prevalent in older adults experiencing multiple non-syncopal falls versus age-matched non-fallers: a pilot study.

BACKGROUND: vestibular disorders are common in the general population, increasing with age. However, it is unknown whether older adults who fall have a higher proportion of vestibular impairment compared with age-matched older adult non-fallers. OBJECTIVE: to identify whether a greater proportion of older adult fallers have a peripheral vestibular impairment compared with age-matched healthy controls. DESIGN: case-controlled study. SETTING: tertiary falls and neuro-otology clinics and local community centres, London, UK. PARTICIPANTS AND METHODS: community-dwelling older adults experiencing: (i) ≥2 unexplained falls within the previous 12-months (Group F, n = 25), (ii) a confirmed peripheral vestibular disorder (Group PV, n = 15) and (iii) healthy non-fallers (Group H, n = 16). All the participants completed quantitative vestibular function tests, the functional gait assessment (FGA), physiological profile assessment (PPA) and subjective measures for common vestibular symptoms (i.e. giddiness), balance confidence during daily activities and psychological state. RESULTS: a clinically significant vestibular impairment was noted for 80% (20/25) of Group F compared with 18.75% (3/16) for Group H (P < 0.01). Group F performed less well in complex gait tasks (FGA), and reported a greater number of falls than both Groups H and PV (P < 0.05). Vestibular symptom scores showed no significant difference between Groups F and PV. CONCLUSION: vestibular dysfunction is significantly more prevalent in older adult fallers versus non-fallers. Individuals referred to a falls clinic are older, more impaired and report more falls than those referred to a neuro-otology department. A greater awareness of vestibular impairments may lead to more effective management and treatment for older adult fallers.

Digital biomarkers from gaze tests for classification of central and peripheral lesions in acute vestibular syndrome.

Acute vestibular syndrome (AVS) is characterised by a sudden vertigo, gait instability, nausea and nystagmus. Accurate and rapid triage of patients with AVS to differentiate central (potentially sinister) from peripheral (usually benign) root causes is a challenge faced across emergency medicine settings. While there exist bedside exams which can reliably differentiate serious cases, they are underused due to clinicians' general unfamiliarity and low confidence interpreting results. Nystagmus is a fundamental part of AVS and can facilitate triaging, but identification of relevant characteristics requires expertise. This work presents two quantitative digital biomarkers from nystagmus analysis, which capture diagnostically-relevant information. The directionality biomarker evaluates changes in direction to differentiate spontaneous and gaze-evoked (direction-changing) nystagmus, while the intensity differential biomarker describes changes in intensity across eccentric gaze tests. In order to evaluate biomarkers, 24 sets of three gaze tests (left, right, and primary) are analysed. Both novel biomarkers were found to perform well, particularly directionality which was a perfect classifier. Generally, the biomarkers matched or eclipsed the performance of quantitative nystagmus features found in the literature. They also surpassed the performance of a support vector machine classifier trained on the same dataset, which achieved an accuracy of 75%. In conclusion, these biomarkers simplify the diagnostic process for non-specialist clinicians, bridging the gap between emergency care and specialist evaluation, ultimately benefiting patients with AVS.

Acceptability of Audiovestibular Assessment in the Home-A Patient Survey.

The COVID-19 pandemic dramatically changed health service delivery with vulnerable patients advised to isolate and appointments provided virtually. This change affected recruitment into an observational cohort study, undertaken at a single site, where participants with mitochondrial disorders were due to have specialist hospital-based audiovestibular tests. To ensure study viability, the study protocol was amended to allow home-based assessment for vulnerable participants. Here, we report outcomes of an online survey of participants who underwent home-based assessment, related to the experience, perceived benefits, and drawbacks of home audiovestibular assessments. Seventeen participants underwent home-based neuro-otological assessment, due to the need to isolate during COVID-19. Following the assessment, 16 out of 17 participants completed an anonymised online survey to share their experiences of the specialist home-based assessment. One hundred percent of participants rated the home-based assessment 'very positively' and would recommend it to others. Sixty-three percent rated it better than attending hospital outpatient testing settings. The benefits included no travel burden (27%) and reduced stress (13%). A majority reported no drawbacks in having the home visit. The patient-reported feedback suggests a person-centred approach where audiovestibular assessments are conducted in their homes is feasible for patients, acceptable and seen as beneficial to a vulnerable group of patients.

Hearing rehabilitation of adults with auditory processing disorder: a systematic review and meta-analysis of current evidence-based interventions.

Background: For adults with auditory processing disorder (APD), listening and communicating can be difficult, potentially leading to social isolation, depression, employment difficulties and certainly reducing the quality of life. Despite existing practice guidelines suggesting treatments, the efficacy of these interventions remains uncertain due to a lack of comprehensive reviews. This systematic review and meta-analysis aim to establish current evidence on the effectiveness of interventions for APD in adults, addressing the urgent need for clarity in the field. Methods: Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic search across MEDLINE (Ovid), Embase (Ovid), Web of Science and Scopus, focusing on intervention studies involving adults with APD. Studies that met the inclusion criteria were grouped according to intervention with a meta-analysis only conducted where intervention, study design and outcome measure were comparable. Results: Out of 1,618 screened records, 13 studies were included, covering auditory training (AT), low-gain hearing aids (LGHA), and personal remote microphone systems (PRMS). Our analysis revealed: AT, Mixed results with some improvements in speech intelligibility and listening ability, indicating potential benefits but highlighting the need for standardized protocols; LGHA, The included studies demonstrated significant improvements in monaural low redundancy speech testing (p < 0.05), suggesting LGHA could enhance speech perception in noisy environments. However, limitations include small sample sizes and potential biases in study design. PRMS, Demonstrated the most consistent evidence of benefit, significantly improving speech testing results, with no additional benefit from combining PRMS with other interventions. Discussion: PRMS presents the most evidence-supported intervention for adults with APD, although further high-quality research is crucial for all intervention types. The establishment and implementation of standardized intervention protocols alongside rigorously validated outcome measures will enable a more evidence-based approach to managing APD in adults.

Exploring Inner Ear and Brain Connectivity through Perilymph Sampling for Early Detection of Neurological Diseases: A Provocative Proposal.

Recent evidence shows that it is possible to identify the elements responsible for sensorineural hearing loss, such as pro-inflammatory cytokines and macrophages, by performing perilymph sampling. However, current studies have only focused on the diagnosis of such as otologic conditions. Hearing loss is a feature of certain neuroinflammatory disorders such as multiple sclerosis, and sensorineural hearing loss (SNHL) is widely detected in Alzheimer's disease. Although the environment of the inner ear is highly regulated, there are several communication pathways between the perilymph of the inner ear and cerebrospinal fluid (CSF). Thus, examination of the perilymph may help understand the mechanism behind the hearing loss observed in certain neuroinflammatory and neurodegenerative diseases. Herein, we review the constituents of CSF and perilymph, the anatomy of the inner ear and its connection with the brain. Then, we discuss the relevance of perilymph sampling in neurology. Currently, perilymph sampling is only performed during surgical procedures, but we hypothesize a simplified and low-invasive technique that could allow sampling in a clinical setting with the same ease as performing an intratympanic injection under direct visual check. The use of this modified technique could allow for perilymph sampling in people with hearing loss and neuroinflammatory/neurodegenerative disorders and clarify the relationship between these conditions; in fact, by measuring the concentration of neuroinflammatory and/or neurodegenerative biomarkers and those typically expressed in the inner ear in aging SNHL, it could be possible to understand if SNHL is caused by aging or neuroinflammation.

Acute positional vertigo in the emergency department-peripheral vs. central positional nystagmus.

Introduction: Benign paroxysmal positional vertigo (BPPV) is the most common cause of positional vertigo. However, positional vertigo can also be due to diseases affecting the central vestibular pathways, such as vestibular migraine. Accurate and timely diagnosis enables effective triage and management. Objectives: To evaluate diagnoses made by emergency clinicians compared to acute vertigo specialists, in patients presenting to an emergency department (ED) with positional vertigo. Methods: Following routine ED care, patients with a primary complaint of dizziness, vertigo, light-headedness or unsteadiness, underwent detailed neuro-otological assessment by acute vertigo specialists. Demographics and final diagnoses were recorded and analyzed. Results: Of 71 consented patients (21-91 years; mean 56 years, ±16.7 years, 40 females), ED identified 13 with a peripheral cause of positional vertigo (mean 48.85 years, ±16.19, 8 females). Central positional nystagmus was not noted in any of the patients with positional vertigo seen by the ED clinicians. Acute vertigo specialists diagnosed nine patients with BPPV (age range 50-88 years, mean 66 years, ±12.22, 5 females), and six with central positional nystagmus (age range 23-59 years, mean 41.67 years, ±15.78, 6 females). Conclusion: Positional vertigo should be assessed with positional maneuvers such as Dix-Hallpike and Roll tests in the ED to identify peripheral and central nystagmus features. Central causes are more common in younger females, with the presence of vomiting, and/or a background of motion sensitivity.

Neuroinflammatory disorders of the brain and inner ear: a systematic review of auditory function in patients with migraine, multiple sclerosis, and neurodegeneration to support the idea of an innovative 'window of discovery'.

Background: Hearing can be impaired in many neurological conditions and can even represent a forme fruste of specific disorders. Auditory function can be measured by either subjective or objective tests. Objective tests are more useful in identifying which auditory pathway (superior or inferior) is most affected by disease. The inner ear's perilymphatic fluid communicates with the cerebrospinal fluid (CSF) via the cochlear aqueduct representing a window from which pathological changes in the contents of the CSF due to brain inflammation could, therefore, spread to and cause inflammation in the inner ear, damaging inner hair cells and leading to hearing impairment identifiable on tests of auditory function. Methods: A systematic review of the literature was performed, searching for papers with case-control studies that analyzed the hearing and migraine function in patients with neuro-inflammatory, neurodegenerative disorders. With data extracted from these papers, the risk of patients with neurological distortion product otoacoustic emission (DPOAE) was then calculated. Results: Patients with neurological disorders (headache, Parkinson's disease, and multiple sclerosis) had a higher risk of having peripheral auditory deficits when compared to healthy individuals. Conclusion: Existing data lend credence to the hypothesis that inflammatory mediators transmitted via fluid exchange across this communication window, thereby represents a key pathobiological mechanism capable of culminating in hearing disturbances associated with neuroimmunological and neuroinflammatory disorders of the nervous system.

Video head impulse testing: Pitfalls in neurological patients.

The video head impulse test (vHIT) assesses the vestibulo-ocular reflex (VOR) during a rapid high-velocity low amplitude (10°-20°) head rotation. Patients with peripheral vestibulopathy have a reduced VOR gain with corrective catch-up saccades during the head turn. There are several pitfalls, mainly technical, which may interfere with interpretation of vHIT data. In addition, intrusive eye movement disorders such as spontaneous nystagmus that affect normal eye position and tracking can affect the vHIT results. To date there has been little study of neurological saccadic eye movements that may interfere with the interpretation of vHIT data. Here, in ten patients with a range of central neurological disorders, we describe oculomotor abnormalities on vHIT in the presence of normal range VOR gain values, recorded at a tertiary vestibular neurology service.

Patient Experience of Flunarizine for Vestibular Migraine: Single Centre Observational Study.

Vestibular migraine (VM) is a leading cause of episodic vertigo, affecting up to 1% of the general population. Despite established diagnostic criteria, there is currently no evidence-based approach for acute treatment of VM, with treatment recommendations generally extrapolated from studies on classical migraine headache. Several small-scale studies have identified flunarizine as a potentially effective prophylactic medication in VM. We conducted a single-centre observational service evaluation study exploring patient experiences of preventative medications over a 28-month period, including flunarizine, for control of VM symptoms. To compare patient experience of flunarizine with other medications, data from patients taking flunarizine were separately analysed. A total of 90% of VM patients taking flunarizine reported symptomatic improvement, compared to only 32% of patients on other medications. Whilst 50% of patients on flunarizine reported side effects. these were not deemed to outweigh the clinical benefits, with most patients deciding to continue treatment. Our data supports the use of flunarizine in VM.

Clinician's perspectives in using head impulse-nystagmus-test of skew (HINTS) for acute vestibular syndrome: UK experience.

BACKGROUND: Acute vestibular syndrome (AVS) features continuous dizziness and may result from a benign inner ear disorder or stroke. The head impulse-nystagmus-test of skew (HINTS) bedside assessment is more sensitive than brain MRI in identifying stroke as the cause of AVS within the first 24 hours. Clinicians' perspectives of the test in UK secondary care remains unknown. Here, we explore front-line clinicians' perspectives of use of the HINTS for the diagnosis of AVS. METHODS: Clinicians from two large UK hospitals who assess AVS patients completed a short online survey, newly designed with closed and open questions. RESULTS: Almost half of 73 total responders reported limited (n=33), or no experience (n=19), reflected in low rates of use of HINTS (n=31). While recognising the potential utility of HINTS, many reported concerns about subjectivity, need for specialist skills and poor patient compliance. No clinicians reported high levels of confidence in performing HINTS, with 98% identifying training needs. A lack of formalised training was associated with onward specialist referrals and neuroimaging (p=0.044). CONCLUSIONS: Although the low sample size in this study limits the generalisability of findings to wider sites, our preliminary data identified barriers to the application of the HINTS in AVS patients and training needs to improve rapid, cost-effective and accurate clinical diagnosis of stroke presenting with vertigo.

Head shaking does not alter vestibulo ocular reflex gain in vestibular migraine.

Vestibular Migraine (VM) is the most common cause of non-positional episodic vestibular symptoms. Patients with VM commonly report increased motion sensitivity, suggesting that vestibular responses to head movement may identify changes specific to VM patients. Here we explore whether the vestibulo-ocular reflex (VOR) gain alters in response to a clinical "headshake" maneuver in patients with VM. Thirty patients with VM in the inter-ictal phase, 16 patients with Benign Positional Paroxysmal Vertigo (BPPV) and 15 healthy controls were recruited. Patients responded to the question "Do you feel sick reading in the passenger seat of a car?" and completed a validated motion sickness questionnaire as a measure of motion sensitivity. Lateral canal vHIT testing was performed before and after headshaking; the change in VOR gain was calculated as the primary outcome. Baseline VOR gain was within normal limits across all participants. There was no significant change in VOR gain after headshaking in any group (p = 0.264). Patients were 4.3 times more likely to be in the VM group than in the BPPV group if they reported nausea when reading in the passenger seat of a car. We postulate that a headshake stimulus may be insufficient to disrupt cortical interactions and induce a change in VOR gain. Alternatively, changes in VOR gain may only be apparent in the acute phase of VM. Reading in the passenger seat of a car was considered uncomfortable in all VM patients suggesting that this specific question may be useful for the diagnosis of VM.