Abstract:
Background
Vestibular dysfunction arising from the central components of the vestibular system
are associated with impaired balance. Due to decreased spontaneous recovery of the
central vestibular system post-stroke, patients may develop maladaptive sensory
strategies in the early months post-stroke in response to the absence of specific
management to address vestibular dysfunction following a stroke.
Methods
A phase 1 cross-sectional survey was conducted to determine the prevalence of
clinical features and activity limitations associated with central vestibular dysfunction
in patients who are in the sub-acute phase post-stroke (N=102). A phase 2 singleblind
cluster randomised controlled trial (RCT) was conducted to determine the effect
of vestibular rehabilitation therapy (VRT) integrated with task-specific activities
received by patients in the experimental group, compared to patients who received
task-specific activities alone in the control group. After central vestibular dysfunction
was diagnosed based on the outcome of the assessment of smooth pursuit or
saccadic eye movement using videonystagmography (VNG) or the assessment of
vestibulo-ocular reflex (VOR)-gain using video head impulse test (vHIT) during the
cross-sectional survey, 60 patients were randomly allocated to either an experimental
group (N=30) or control group (N=30). Patients in the experimental group received a
combination of VRT integrated with task-specific activities as part of the treatment as
an “add-on” intervention compared to patients in the control group who received taskspecific
activities alone during the two-week intervention period.
Results
A high prevalence of clinical features associated with central vestibular dysfunction,
including impairment of smooth pursuit eye movement (97.1%-99.0%), utricle and
superior vestibular nerve function (97.1%) and higher vestibular function (97.1%),
were observed. A high prevalence of activity limitations associated with central
vestibular dysfunction, including impaired functional ability (98.0%), ability to modify
gait in response to changing task demands (97.1%) and functional balance (87.3%),
were also observed in the current study. Findings of the single-blind cluster RCT demonstrated that between-group comparison
based on logistic regression adjusted for age, gender and race, patients in the
experimental group that received VRT integrated with task-specific activities improved
significantly more in oculomotor function, specifically saccadic movement (velocity and
accuracy), level of depression and functional ability, compared to patients in the
control group who received task-specific activities alone.
Conclusion
The high prevalence of clinical features and activity limitations associated with central
vestibular dysfunction on body structure and function, as well as activity level in
patients post-stroke, may suggest that the measurement of these clinical features and
activity limitations associated with central vestibular dysfunction might be a robust
biomarker that may be applied in the guidance and interpretation of treatment
outcomes post-stroke.
Findings of the study adds to an increasing body of evidence that the CNS has the
capability to compensate for central vestibular dysfunction and re-weight sensory
inputs post-stroke. Input from the visual system may compensate for the loss of
vestibular information and is thus a substitute as a reference for earth vertical in
controlling posture and trunk stability.
Implication
Vestibular rehabilitation therapy integrated with task-specific activities are a low cost,
safe and effective complement to standard treatment of stroke patients.