Date of Submission

11-6-2018

Abstract

Vestibular disorders significantly impact a person’s quality of life and daily function with symptoms such as dizziness, vertigo, visual disturbances and balance impairment. Vestibular disorders commonly cause hospital presentations and are often under diagnosed and therefore mis-managed in the emergency department (ED) and acute medical environment (AME). There is a lack of research assisting clinicians in identifying and managing vestibular disorders in these settings. There is also limited evidence concerning the effectiveness of a physiotherapy vestibular service in the acute hospital setting for managing non-emergent vestibular disorders (non-life threatening).

The primary aim of this thesis was to improve the service model of care (screening and physiotherapy clinical intervention) of people who present to hospital with non-emergent vestibular disorders. The sequence of studies involved in this research program were conducted as two phases and aimed to 1) construct and validate a new vestibular screening tool (VST) for use in the ED / AME to guide referral to physiotherapy vestibular rehabilitation; 2) determine the clinical effectiveness of a hospital based, physiotherapy-led vestibular service, and 3) compare an immediate physiotherapy intervention pathway with a delayed intervention pathway.

The background of the thesis highlights the high prevalence of vestibular disorders and contextualises the need for a clinical questionnaire to assist in the identification of such disorders in the ED / AME. The thesis includes a systematic review (Paper 1) demonstrating the lack of existing self-report questionnaires appropriate for use in the acute hospital setting. The systematic review utilised the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist to test the quality of existing patient-reported measures / screening tools.

Phase one of the thesis includes the construction and validation of a new questionnaire, the VST, to guide referral to physiotherapy vestibular rehabilitation. The first paper of Phase one (Paper 2) describes a methodological study undertaken in the ED / AME of a metropolitan hospital with adults (N = 114) presenting to hospital with dizziness complaints. The construction of the VST was based on two longer questionnaires identified in the systematic review, the dizziness handicap inventory (DHI) and the vestibular rehabilitation benefit questionnaire. The Rasch measurement model was utilised to develop the construct validity of the VST; factor analysis demonstrated unidimensionality; whilst Cronbach α statistic identified internal consistency of the VST. Receiver operating characteristic curves tested three versions of the VST for sensitivity and specificity. The 4-item VST had the greatest area under the curve (.894) with highest sensitivity (83%) and specificity

(84%) for identifying non-emergent vestibular disorders (cut-off value ≥ 4 / 8). The VST showed high inter-rater and intra-rater reliability.

The next paper of Phase one (Paper 3), describes a longitudinal prospective study, undertaken with adults (N =195) presenting to hospital with non-emergent vestibular disorders. Physiotherapy vestibular diagnostic tests categorised people into vestibular or non-vestibular groups. The VST and DHI were completed concurrently at 3 time-points with participants who received vestibular rehabilitation intervention. The VST was found to have concurrent validity against the DHI, across the continuum of care. The VST also demonstrated responsiveness to change after vestibular rehabilitation intervention.

Phase two, which deals with investigating aims 2 and 3 of the thesis, includes a prospective observational study (Paper 4), which determined the immediate and longer-term clinical effectiveness of a new vestibular rehabilitation service within the hospital setting (N = 193). Baseline, discharge and follow-up outcomes were reported. Linear mixed models determined significance of the mean difference of measures across the continuum of care. People had significantly reduced dizziness / vertigo symptoms and significantly improved mobility at discharge, which was maintained 3-months post discharge (p ≤ 0.001).

Recent research has suggested that early intervention of vestibular disorders is important. However, the best time to commence vestibular rehabilitation requires investigation. Therefore, Phase two (Paper 4) also tested the outcomes of people immediately referred to the physiotherapy vestibular service; compared to those referred through a waitlist, delayed pathway. Both immediate and delayed intervention groups reported significantly reduced dizziness / vertigo impairment (p ≤ 0.001), but only the immediate group significantly improved in all mobility measures (p ≤ 0.005). Resultant symptoms and functional impact of a vestibular disorder did not significantly subside to normal without vestibular rehabilitation, even 3-weeks after presenting to hospital.

The results of this thesis, including the construction and validation of the VST, may clinically assist with screening and therefore referral to physiotherapy vestibular services. The validation of the VST provides a clinically useful tool for a hospital setting. Findings from this research support the clinical effectiveness of a hospital-based physiotherapy vestibular service. Finally, results indicate immediate referral to physiotherapy vestibular services should be considered.

School/Institute

School of Physiotherapy

Document Type

Thesis

Access Rights

Open Access

Extent

402 pages

Degree Name

Doctor of Philosophy (PhD)

Faculty

Faculty of Health Sciences

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