Dizziness, Migraine, Motion Sickness, Vestibular Disorder, Vestibular Migraine, Vestibular Schwannoma
Conditions
Keywords
sensory integration, cochlear implant, vestibular implant, balance, dizziness, vestibular disorders
Brief summary
Multiple sensory cues are typically generated by discrete events, and while they do not reach the cerebrum simultaneously, the brain can bind them temporally if they are interpreted as corresponding to a single event. The temporal binding of vestibular and non-vestibular sensory cues is poorly understood and has not been studied in detail, despite the fact that the vestibular system operates in an inherently multimodal environment. In this study, the researchers are investigating the physiology and pathophysiology of vestibular temporal binding by studying normal subjects, patients with peripheral and central vestibular dysfunction, and patients with vestibular and cochlear signals provided by prosthetic implants in the inner ear.
Detailed description
Multiple sensory cues are generated by discrete events (e.g., the vestibular-visual signals after hitting a pothole) and while they do not reach the cerebrum simultaneously, the brain can synthesize them if they are interpreted as corresponding to a single event. This is critical because the central representation of an event is improved if two or more relevant cues are integrated but conversely is degraded if unrelated inputs are synthesized. Little research has focused on temporal binding of vestibular signals with other sensory cues, even though the vestibular system operates in an inherently multimodal environment, and virtually nothing is known about temporal binding abnormalities in patients with peripheral or central vestibular disorders. The investigators will use psychophysical tests (quantifying the PSS \[point of subjective simultaneity\] and TBW \[temporal binding window\]) to study vestibular temporal binding in normal people, patients with combined vestibular and cochlear prostheses, and patients with peripheral or central vestibular dysfunction. The researchers will investigate two fundamental aspects of temporal binding: its dependence on signal precision and adaptation driven by habitual exposure to sensory patterns. Furthermore, the researchers will investigate how and why temporal binding differs from normal in patients with peripheral and central vestibular dysfunction.
Interventions
BEHAVIORALTemporal Binding Adaptation - PSS training
After the PSS and TBW are calculated with the standard TOJ paradigm, 100 training trials are provided where the SOA is set to a PSS slightly greater than what was the mean calculated for normal subjects, with the goal of shifting the PSS in a direction associated with better clinical vestibular parameters and vestibular precision measurements (e.g. standard rotational testing VOR time constant, lower DHI, higher FGA score) . Then the TOJ task will be repeated but every 10 testing trials will be followed by 10 training trials (SOA = PSS desired or mean normal PSS), and this pattern will be repeated 10 times to 100 more training trials interspersed with the Post TOJ data. Subjects will respond after all trials and testing and training will not be distinguished. After this is completed, the new PSS and TBW are calculated. Sham PSS training will be identical to the above except that the 'training' period will consist of random SOAs rather than a series of fixed SOAs.
BEHAVIORALTemporal Binding Adaptation - PSS adaptation with VI stimulation
The adaptation will utilize the same approach used in non-implanted patients. The investigators will provide a repeated, fixed SOA with either the CI or VI leading the other stimulus by 220 ms. After the training period, which will match the number of stimuli pairs provided to our normal vestibular-auditory control subjects undergoing PSS adaptation, the TOJ study is repeated to recalculate the PSS and TBW.
BEHAVIORALChronic Motion-modulated Stimulation
To provide 8 hours of 'physiologic' CI and VI inputs during normal activities, the investigators will employ standard motion-modulated stimulation with the VI. This requires pre-adaptation to a 200 pps tonic stimulation rate (to emulate the push-pull design of the native vestibular system allowing modulating stimulation upward or downward with opposite directions of motion). The three electrodes are connected to the head-mounted prosthetic circuit, which consists of three angular velocity sensors (one aligned with the sensitive axis of each canal) such that head rotations in the plane of the given canal modulate the stimulation rate of the corresponding electrode, upward (for ipsi) or downward (for contralateral) head rotations, thereby simulating normal canal-mediated modulations.
Sponsors
National Institute on Deafness and Other Communication Disorders (NIDCD)
Oregon Health and Science University
University of Geneva, Switzerland
Massachusetts Eye and Ear Infirmary
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
8 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
Normal subjects * normal vestibular-oculomotor exams * normal low-frequency standard rotational testing * normal hearing Migraine * meets International Headache Society (IHS) criteria for migraine with or without aura * tested more than 2 weeks after most recent migraine headache Vestibular Migraine * meets Barany Society criteria for vestibular migraine, which includes: * episodic vestibular symptoms that occur with headaches that meet the IHS criteria for migraine * tested more than 2 weeks after most recent migraine headache or vestibular episode Vestibular Schwannoma * existence of unilateral vestibular schwannoma (pre & post clinical intervention e.g. surgical resection) * must plan to have clinical intervention such as sub-occipital surgical approach with complete sectioning of the vestibular nerve * rotational testing to assess pre-surgical vestibular function * audiogram * brain MRI consistent with vestibular schwannoma * audiography in each ear Vestibular (VI) and Cochlear (CI) Implant subjects * scheduled for CI surgery because of deafness * minimum 5 year history of documented absence of auditory and vestibular function, based on review of their audiograms and vestibular tests * specific vestibular criteria: peak ice water caloric response of less than 3deg/s for each ear; yaw VOR time constant \<3s and gain \<0.25; and reduced head impulse gain (\<0.25) for all canal planes * specific audiographic criteria: 80dB or greater sensorineural hearing loss in both ears
Exclusion criteria
Normal subjects * history of otologic or neurologic disease * on vestibular suppressant medication (benzodiazepine, antihistamine, anticholinergic) * pregnant or recently (\<6mos) pregnant Migraine * history of vestibular symptoms (other than motion sickness) * evidence of other neurologic or otologic dysfunction * on migraine prophylactic medications * on vestibular suppressant medication (benzodiazepine, antihistamine, anticholinergic) Vestibular Migraine (VM) * other neurologic or otologic dysfunction as defined above except for central eye movement findings that are consistent with VM and therefore not exclusionary. * on migraine prophylactic medication * on vestibular suppressant medication (benzodiazepine, antihistamine, anticholinergic) Vestibular Schwannoma * other otologic disease (other than presbycusis) or any neurologic disease (other than migraine) * on vestibular suppressant medication (benzodiazepine, antihistamine, anticholinergic)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in postural sway/balance | baseline and post-PSS adaptation (1 hour) | Measurements of postural sway during Romberg testing on floor and foam (including an extra 60s balance test during which subject stands on foam and shakes head left and right at 1hz frequency while fixating on a point a set distance away) pre & post temporal binding adaptation (TBW & PSS training). |
| Change in rapid measure of gait | baseline and post-PSS adaptation (1 hour) | This measure is scored before and after PSS adaptation in UVD (unilateral vestibular dysfunction) patients. Gait is scored by performance on a task derived from the FGA (walking 40 feet while turning the head from side to side). It is scored on a 0 to 10 visual scale and provides a rapid assessment of vestibular function pre and post adaptation. |
| Change in measure of inducible dizziness | baseline and post-PSS adaptation (1 hour) | Looking at the change between before and after PSS adaptation in UVD (unilateral vestibular dysfunction) patients. Inducible dizziness is the symptom severity provoked by a task derived from the FGA (walking 40 feet while turning the head from side to side). It is scored on a 0 to 10 visual scale and provides a rapid assessment of vestibular function pre and post adaptation. |
| Change in Point of Subjective Simultaneity (PSS) | baseline and 1 hour post 8-hour VI-CI 'physiologic' stimulation | Pre and post chronic motion-modulated stimulation in CI/VI patients - the PSS will be measured during temporal binding testing |
Countries
United States
Outcome results
None listed