The Virtual (Telemedicine) Vestibular Examination

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This document is based on Approach to the Ocular Motor & Vestibular History and Examination: https://collections.lib.utah.edu/ark:/87278/s64x9bq1, but adapted and edited for the telemedicine exam. Virtual vestibular examination • Dix-Hallpike Maneuver: used to test for posterior canal (PC) BPPV. The patient can be guided through a self-administered Dix-Hallpike (DH) maneuver using two techniques. The safety of the patient should be prioritized when completing these tests virtually, and the examiner should avoid putting the patient in a position where a fall may occur. When the test is positive [https://collections.lib.utah.edu/details?id=1281863&q=dix+hallpike&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold], the nystagmus 1) typically begins with a short latency (sometimes as long as 30 secs) after change in head position, 2) lasts less than 1 min, 3) fatigues with repeated testing, and 4) often reverses direction (downbeat-torsional towards the left ear with right PC-BPPV) when the patient sits up again [https://collections.lib.utah.edu/details?id=1281864&q=dix+hallpike&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold]. o Floor (or bed) Dix-Hallpike: this test can be used for patients who are fully mobile and able to get down to the floor and up again without assistance. Instruct the patient to sit upright on the floor and place a pillow directly behind them (which will align to their mid-back when lying supine). Then have the patient turn their head 45o to the right/left and lie back quickly, with proper placement of the pillow allowing the head/neck to extend slightly as they lie back. The patient should hold the camera in front of their eyes throughout the maneuver. Assess for nystagmus and symptom provocation. If dizziness is provoked, allow the patient sufficient time to recover before instructing them to sit up. Have the patient keep the camera on the eyes as they sit up to see if there is reversal of the nystagmus (see example in PC-BPPV - https://collections.lib.utah.edu/ark:/87278/s6ng8nbm). o Modified (chair) Dix-Hallpike:(1) this test can be used for patients who may not be able to safely undertake the traditional Dix-Hallpike. Instruct the patient to sit at the front of the chair, turn their head 45o to the right/left and sit back quickly, allowing their neck to extend slightly over the back of the chair. The patient should hold the camera in front of their eyes throughout the maneuver. Assess for nystagmus and symptom provocation. If dizziness is provoked, allow the patient sufficient time to recover before instructing them to sit up. When nystagmus is provoked, continue to observe the eyes after returning to an upright seated position to evaluate for reversal. • Supine roll test: used to test for horizontal canal (HC) BPPV. While horizontal nystagmus due to HC-BPPV is often seen with DH, the roll test will usually maximize nystagmus and vertigo with the HC variant. The patient can be guided through a self-administered supine roll test while lying on the floor or bed. Instruct the patient to lie supine with a pillow under their head (so the head is flexed 20-30o, making the HC perpendicular to the ground), then turn their head (or their whole body and head) 90o to the right/left. Assess for nystagmus and symptom provocation, and instruct the patient to return to the initial supine position before testing the opposite side. Nystagmus seen in HC BPPV may be geotropic (https://collections.lib.utah.edu/details?id=1281862&q=horizontal+canal+bppv&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold) or apogeotropic (https://collections.lib.utah.edu/details?id=1281861&q=horizontal+canal+bppv&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold), and the nystagmus is more intense when beating toward the affected ear. If dizziness is provoked, allow the patient sufficient time to recover before instructing them to sit up. • Active head impulse test (HIT): instruct the patient to fix their eyes on the camera and turn their head 20o to the right/left, and then make a rapid movement toward the midline to align their head with the camera again, keeping their eyes fixed on the camera throughout. A simple instruction is to ask the patient to move the head from the initial eccentric position back to a neutral position as quickly as they can. The test can also be completed with rapid movements away from the midline (thus making the maneuver less predictable for the patient - however, it is not clear that one method is superior to the other for the purposes of the active HIT). In the case of an acute right peripheral vestibulopathy (e.g., vestibular neuritis), a rightward HIT will result in the eyes moving to the right with the head initially, so that a corrective re-fixation saccade will be needed to move the eyes back to the target, or to the left. This is considered an abnormal or positive HIT and generally suggests a peripheral process (although there are exceptions). Note that a mildly abnormal HIT may not be detectable virtually, as patients may struggle to achieve the same rapid velocity of head movement and rapid deceleration that are controlled by the examiner during the passive bedside HIT (https://collections.lib.utah.edu/details?id=187678). Also, the unpredictability of the passive (bedside) HIT makes it more challenging for patients to make compensatory (covert) saccades during the head movement. Even a patient with known severe vestibular loss may or may not have an abnormal active HIT (see example - https://collections.lib.utah.edu/ark:/87278/s6d84xrj). • Dynamic Visual Acuity: the examiner can use screen-sharing to provide a visual acuity chart. Instruct the patient to sit at the appropriate distance from their screen at which the lowest line on the visual acuity chart is just readable. Have the patient move their head (horizontally to evaluate the horizontal SCC and vertically to evaluate the anterior and posterior SCC function) at ~2 Hz while viewing the chart. A decrease in best-corrected acuity of 2 lines or more from baseline is considered abnormal - patients with unilateral vestibular loss may loss 2-3 lines prior to compensation, while patients with bilateral vestibular loss will often lose 4 or more lines. Encourage the patient to keep moving their head throughout, as patients may have a natural tendency to slow or interrupt their active head movements in order to best visualize the target. • Penlight cover test (partial removal of fixation): during in-person clinical encounters, the maneuvers below are best tested with complete (or near complete) removal of fixation (e.g., Frenzel or video Frenzel goggles). Removal of fixation is more challenging during virtual evaluations but can be approximated using the penlight cover test. Instruct the patient to go into a dark area and shine a light from a cell phone or torch into one eye (holding the light source at a distance of 2-3 inches from the eye to make fixation more challenging due to the brightness of the light) while occluding the fellow eye with the other hand. Assess for spontaneous nystagmus or nystagmus in eccentric gaze. If a dark area is not available, the following tests can be completed in normal lighting, but abnormalities may be more subtle since removal of fixation will accentuate peripheral vestibular nystagmus. o Head-shaking: instruct the patient to close their eyes and perform active rapid head-shaking at 2-3 Hz for ~15 secs. If a unilateral vestibulopathy is present, head-shaking-induced (contralesional) nystagmus is often provoked, with the slow phase toward the affected ear. With central lesions, the nystagmus may be vertical (see example - https://collections.lib.utah.edu/details?id=1550674&q=hyperventilation&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold) or may change direction from the baseline spontaneous nystagmus. If there's strong HSN without clear unilateral vestibular loss (https://collections.lib.utah.edu/details?id=1295175), think about a central process. o Hyperventilation: instruct the patient to breathe rapidly in and out of their mouth for 40-60 seconds. Alkalosis and changes in ionized calcium may improve conduction through an affected segment of 8th cranial nerve due to vestibular schwannoma (https://collections.lib.utah.edu/details?id=1213447) or neurovascular compression, usually causing an excitatory (ipsilesional) nystagmus. When a chronic vestibular imbalance has been compensated for by central mechanisms, hyperventilation can cause a transient decompensation and bring out nystagmus with an ipsilesional slow phase. Hyperventilation can enhance/produce downbeat nystagmus in cerebellar disease (https://collections.lib.utah.edu/details?id=1427580&q=hyperventilation&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold). o Valsalva (closed glottis or pinched nose): instruct the patient to take a deep breath and ‘bear down' (closed glottis) or take a deep breath and ‘try to pop their ears' (pinched nose). Assess for nystagmus. In superior canal dehiscence, pressure changes may be transmitted to the superior canal, causing an excitatory pattern of nystagmus with the nose pinched (https://collections.lib.utah.edu/details?id=1307322&q=valsalva&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold), or an inhibitory pattern with Valsalva against a closed glottis. o Vibration: instruct the patient to self-administer this test with an electric toothbrush or vibrator/massager, if available. Vibration of the mastoids and vertex will induce an ipsilesional slow phase with unilateral vestibular loss (https://collections.lib.utah.edu/details?id=1427582&q=vibration&fd=title_t%2Cdescription_t%2Csubject_t&facet_setname_s=ehsl_novel_gold). 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This video demonstrates one approach to performing the vestibular examination virtually in a normal subject https://collections.lib.utah.edu/ark:/87278/s6sj78fz. (Video created with the assistance of Dr. Olwen Murphy)