Mackenzie Vestibular common mistakes
Mackenzie Vestibular · Understand the traps and how to avoid them.
Naming the canal involved in BPPV from the symptom story alone and starting a repositioning maneuver without first confirming the characteristic torsional-upbeating nystagmus on a Dix-Hallpike or supine roll test.
Candidates memorize that 'posterior canal is most common' and skip the diagnostic step under time pressure, or they treat a positive history of positional vertigo as equivalent to a confirmed canal localization.
What to do instead
Always perform and describe the provoking test first: Dix-Hallpike for vertical canal, supine roll for horizontal canal. State the observed nystagmus direction, latency, duration, and fatigability, then select the maneuver that matches the identified canal and side.
Performing a canalith repositioning maneuver with the head hanging over the edge of the bed and no support, or allowing the patient to sit up abruptly between positions, on a patient with neck pathology or mobility limitations.
Candidates focus on the geometric sequence of the maneuver and forget the safety envelope: cervical spine clearance, fall risk, and the need for a second person or gait aid after the procedure.
What to do instead
Screen for cervical spine disease, recent surgery, and balance/fall risk before positioning. Use a supported setup, keep the patient's shoulders on the surface, move slowly through each position, and observe the patient seated for several minutes before ambulation.
Interpreting a head impulse test as 'normal' when the clinician performed a small, slow, or unpredictable head thrust, or when the patient made corrective saccades that were missed because the examiner did not watch the eyes continuously.
The test is technically demanding; candidates under-rotate the head or break fixation, and covert saccades are easy to miss without high-speed video or careful observation.
What to do instead
Deliver brief, high-acceleration, unpredictable thrusts of about 10-20 degrees with the patient fixating a target. Watch for both overt and covert catch-up saccades; if bedside results are equivocal, corroborate with vHIT rather than declaring the reflex intact.
Treating a normal bithermal caloric result as proof that the peripheral vestibular system is intact, ignoring that caloric testing probes only low-frequency horizontal canal function.
Candidates conflate 'VNG was normal' with 'vestibular system is normal' and stop the workup, missing high-frequency deficits or vertical canal and otolith involvement.
What to do instead
Interpret each test by the frequency band and canal it probes: caloric for low-frequency horizontal, vHIT for high-frequency canals, VEMP for otolith pathways. Assemble a canal-by-canal and frequency-by-frequency picture before concluding normality.
Reading a VNG report as a single 'percent asymmetry' number and calling it abnormal without checking calibration, fixation suppression, and whether the asymmetry exceeds the laboratory's normative cutoff with adequate slow-phase velocity.
Candidates memorize a single threshold (for example, 25 percent) and apply it mechanically without considering test quality, artifact, or the clinical context that determines whether the finding is peripheral or central.
What to do instead
Review the raw tracing: calibration validity, presence of artifact, slow-phase gain, and fixation index. Compare against the lab's age-matched norms, then integrate with the bedside exam and history rather than acting on one number.
Prescribing a generic vestibular rehabilitation handout of gaze stabilization and balance exercises without tailoring to the diagnosis, the affected side, or the patient's functional goals and fall risk.
Candidates default to a standard exercise list because it is easy to recall, and they skip the assessment of compensatory strategies, secondary anxiety, and activity avoidance that drive outcomes.
What to do instead
Base the plan on the identified deficit: side-specific gaze stabilization, habituation graded to symptom provocation, canal-specific repositioning, and balance/gait tasks matched to the patient's environment. Set measurable goals and a review interval, and document the rationale.
Attributing acute prolonged vertigo with nystagmus that does not suppress with fixation, plus new truncal ataxia or other neurologic signs, to vestibular neuritis and sending the patient home without urgent imaging or stroke evaluation.
Candidates anchor on the common peripheral diagnosis and under-weight the HINTS components and vascular risk factors; posterior circulation stroke can mimic neuritis closely.
What to do instead
Apply HINTS systematically (head impulse, nystagmus type, test of skew) and treat any central pattern, new focal deficit, or high vascular risk as an emergency requiring urgent stroke workup. Document the reasoning and the escalation explicitly.
Clearing a concussed patient for return to sport or driving on symptom resolution alone, without a graded exertion challenge or assessment of dynamic visual acuity, gait, and autonomic response.
Candidates equate 'no headache today' with recovery and skip the provocation testing that reveals exercise intolerance or persistent postural-perceptual dizziness.
What to do instead
Use a stepwise exertion progression with symptom and vital-sign monitoring, test dynamic visual acuity and gait under dual-task conditions, and document clearance criteria and restrictions in writing.
Writing a note that records only the final interpretation ('consistent with right posterior canal BPPV') without the observed findings, maneuvers performed, patient response, and post-procedure instructions.
Candidates document conclusions rather than the data and actions that support them, which fails audit standards and makes handoff or repeat testing unreliable.
What to do instead
Record the specific tests and their results (nystagmus direction and latency, head impulse findings, caloric values), the maneuver and number of cycles, the patient's tolerance, and written aftercare and follow-up instructions.
Failing to screen for red flags before vestibular testing or rehabilitation, such as undiagnosed cardiac arrhythmia, vertebrobasilar insufficiency, or a recent cervical injury, and proceeding with provocative positioning anyway.
Candidates treat vestibular assessment as low-risk and skip the history elements that change the plan, especially when the referral is vague or the schedule is tight.
What to do instead
Build a standard pre-test screen into every encounter: cardiovascular history, neck and vascular symptoms, medications, pregnancy, and fall risk. Document the screen, modify or defer provocative testing when positive, and refer appropriately.