Migraine-anxiety related dizziness (MARD): a new disorder?
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Anxiety↗
Biomedical subjects
J M Furman
Publications and source records attributed to J M Furman.
Cognitive requirements for vestibular and ocular motor processing in healthy adults and patients with unilateral vestibular lesions.
This study investigated the role of cognition in the vestibulo-ocular reflex (VOR) and ocular pursuit using a dual-task paradigm in patients with unilateral peripheral vestibular loss and healthy adults. We hypothesized that cognitive resources are involved in successful processing and integration of vestibular and ocular motor sensory information, and this requirement would be greater in patients with vestibular dysfunction. Sixteen well-compensated patients with surgically confirmed absent unilateral peripheral vestibular function and 16 healthy age- and sex-matched controls underwent seven combinations of vestibular-only, visual-only, and visual-vestibular stimuli while performing three different information processing tasks. Visual-vestibular stimuli included a semicircular canal and an otolith stimulus provided through seated chair rotations; fixation on a laser target and sinusoidal smooth pursuit while still; and fixation on a head-fixed laser target during chair rotations. The information processing tasks were three different auditory reaction time (RT) tasks: (1) simple RT, (2) disjunctive RT, and (3) choice RT. Our results showed increases in RTs in both patients and controls under all vestibular-only stimulation conditions and during ocular pursuit. Patients showed greater increases in RTs during vestibular stimulation and the more complex disjunctive and choice RT tasks. No differences between the groups were found during the visual-only or visual-vestibular interaction conditions. These results reveal interference between vestibulo-ocular processing and a concurrent RT task, suggesting that the VOR and the ocular motor system are dependent upon cognitive resources to some extent, and thus, are not fully automatic systems. We speculate that this interference with cognition occurs as a result of the sensory integration required for resolving inputs from multiple sensory streams. The particularly large decrement in information processing task performance of the patients compared with controls during vestibular stimulation suggests that compensation for unilateral vestibular loss requires continued cognitive resources.
Acoustic Stimulation↗
The steady-state postural response to continuous sinusoidal galvanic vestibular stimulation.
Galvanic vestibular stimulation (GVS) applied between the mastoids during quiet standing elicits postural sway. The aim of this study was to characterize the postural sway response to continuous sinusoidal GVS across various stimulus frequencies and amplitudes. Binaural bipolar sinusoidal GVS was applied to the skin overlying the mastoid processes of 10 subjects while they stood on a force plate with eyes closed. The position of the center of pressure (COP) at the feet was recorded from a forceplate, while the head displacement was measured with a magnetic position tracking system. The stimulus conditions included four frequencies (0.1, 0.25, 0.45, and 1.1 Hz) and five peak amplitudes (0.05, 0.1, 0.25, 0.5, and 1.0 mA). Each subject experienced one trial at each amplitude-frequency pair. Additionally, each subject underwent three trials in which a dual-frequency stimulus (0.1 plus 0.45 Hz at a peak of 0.5 mA each) was presented. The stimuli elicited sway in the frontal plane in all subjects, as evidenced by changes in the displacement of the COP and head. Sway magnitude decreased with increasing stimulus frequency and increased with increasing stimulus amplitude. However, the response magnitude saturated at higher stimulus amplitudes. Phase lag increased with increasing stimulus frequency. The response to the dual-frequency stimulus was reduced at 0.1 Hz and nearly equal at 0.45 Hz in comparison with the single-frequency responses. This study suggests that the postural sway response is nonlinear due to saturation and violation of the principle of superposition.
Adult↗
The "practical mathematics" of recording three-dimensional eye position using scleral coils.
The "gold standard" for recording the three-dimensional rotation of the eye involves placing two coils of wire, embedded in a soft plastic ring, on the sclera of the eye, then placing the subject inside a set of orthogonal oscillating magnetic fields, and using the currents induced in the eye coils to deduce the position of the coil, and hence of the eye, in space. Eye movements are actually eye rotations, which can be described mathematically by a special class of matrices, rotation matrices, or, alternatively, by a rotation vector related to the axis of the rotation. This article deals with the mathematical tools needed to implement the signal processing from such a multifield, dual-coil system and compute the precise rotational movement of the eye. One reason for making such careful measurements is to study an interesting constraint on eye movements, called Listing's law, which expresses ocular torsion, or rotation of the eye about its line of sight, in terms of the direction of gaze. Techniques for experimentally quantitating these constraints are also presented. Following a treatment of the "ideal" case, with coils and eye in perfect alignment, the additional techniques for dealing with various departures from ideality that are almost always encountered experimentally are examined. A final section deals with developing a validation protocol for eye movement analysis techniques using mechanical and computer simulations of eye movements.
Algorithms↗
Semicircular canal-otolith organ interaction during off-vertical axis rotation in humans.
The aim of this study was to examine the interaction of signals from the semicircular canals and the otolith organs during off-vertical axis rotation (OVAR). We recorded horizontal eye position using electro-oculography in 22 young normal human subjects and stimulated the vestibulo-ocular reflex with both constant velocity trapezoids and sinusoidal yaw rotations, using both earth-vertical axis rotation (EVAR) and OVAR. We found that per-rotatory long vestibulo-ocular reflex (VOR) time constants during velocity trapezoids were shorter for OVAR than for EVAR, suggesting a reduction in the efficacy of the velocity storage system during OVAR. However, when we tested with very-low-frequency sinusoids (0.01 Hz and below), the phase lead of the VOR re head velocity was smaller during OVAR than EVAR, suggesting a longer time constant and enhanced efficacy of velocity storage during OVAR. These rotational responses can be explained by two competing influences of signals from the otolith organs, one that diminishes the effectiveness of velocity storage and another that contributes to an estimate of head velocity.
Acceleration↗
Attention influences sensory integration for postural control in older adults.
This study investigated the influence of attention on the sensory integration component of postural control in young and older adults. Eighteen young and 18 older healthy subjects performed information-processing tasks during different postural challenge conditions. Postural conditions included seated, standing on a firm surface, standing on a sway-referenced floor, and standing on a sway-referenced floor while viewing a sway-referenced scene. During each condition, reaction time (RT) was measured during two simple and one inhibitory RT tasks. For the inhibitory task, the time required to inhibit an action was derived, termed the inhibitory time (IT). Performing a RT task was associated with increased postural sway in older subjects, but not in young subjects. The greatest influence of RT task on sway of older subjects was found during the sway-referenced floor/sway-referenced scene condition. Conversely, postural condition had an influence on RT task performance in both young and older subjects. The IT was increased in both young and older subjects only during the sway-referenced floor/scene condition. These results suggest that the sensory integration component of postural control in particular seems to require attention. Further, our data suggest that attentional processes related to inhibitory control are engaged when sensory integration requirements are high.
Age Factors↗
Otolith function after acoustic neuroma surgery.
The response of the vestibular system after acoustic neuroma surgery was investigated in nine patients. The otolith system was studied by means of ocular counterrolling, assessed by video oculography. Horizontal vestibulo-ocular reflex (VOR) function was tested by the sinusoidal harmonic acceleration test using electronystagmography. The results were compared with those obtained from a normal control population. The response to slow rotation tests was symmetric, but the gain was significantly reduced when compared to the normal population. Phase lag was significantly increased. No difference in ocular torsion was observed with lateroflexion of the head to the ipsilateral side in comparison with lateroflexion to the contralateral side. Moreover, the overall ocular counterrolling was well within normal limits. We conclude that the semicircular canal response differs from the otolith response. The component of the torsional VOR mediated by otolith stimulation appears to be more robust than the horizontal VOR mediated mainly by the horizontal semicircular canal system. Ocular counterrolling induced by lateroflexion does not reveal abnormalities in patients with surgically produced unilateral peripheral loss.
Adult↗
Physical therapy outcomes for persons with bilateral vestibular loss.
OBJECTIVE: The purpose of the study was to assess the efficacy of physical therapy for patients with bilateral vestibular loss. STUDY DESIGN: Retrospective case series. METHODS: Twenty-four patients with a diagnosis of bilateral vestibular loss were identified by a retrospective chart review. Thirteen of the 24 patients met the inclusion criteria of having a moderate or greater loss of vestibular function bilaterally as rated by an otoneurologist based on the patient's vestibular function tests. These patients were treated with a custom-designed physical therapy program for a mean of 4.6 visits over an average period of 3.8 months. Patients completed the Dizziness Handicap Inventory and the Activities-specific Balance Confidence Scale at initial evaluation and discharge. Patients were asked to perform the balance and gait tasks of the Dynamic Gait Index, Sensory Organization Test of computerized dynamic posturography, and the Timed "Up and Go" test at their first and last physical therapy sessions. The number of falls in the previous 4 weeks and the use of an assistive device at initial evaluation and discharge were reported. Composite score, an overall score of clinical outcome, was calculated to determine clinically significant changes in physical performance and subjective information. RESULTS: On a population basis, statistically significant improvement was observed after physical therapy for each of the outcome measures including the composite score (P < .05). Clinically significant changes were demonstrated by 33% to 55% of the patients on the various outcome measures. No change was noted in the patients' risk of falling, their number of falls, and the use of assistive devices. CONCLUSION: Many patients with bilateral vestibular loss benefit from an individualized vestibular physical therapy exercise program based on improved physical function and reduced self-perceived levels of handicap.
Accidental Falls↗
Psychiatric consequences of vestibular dysfunction.
Anxiety and dizziness are co-morbid symptoms in a larger percentage of patients than would be expected from chance alone. Such patients have an increased handicap and poorer prognosis. In this review, we discuss the interface between vestibular disorders and anxiety disorders. The two conditions are functionally related via both somatopsychic and psychosomatic mechanisms, and are linked via overlapping neural circuits that include monoaminergic pathways and the parabrachial nucleus network. An alternative conceptualization to the common notion of 'psychogenic' dizziness is presented. Implications for patient management are discussed.
Anxiety↗
Interface between vestibular dysfunction and anxiety: more than just psychogenicity.
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Anxiety Disorders↗
Effect of aging on the otolith-ocular reflex.
We assessed the influence of age on the otolith-ocular reflex and semicircular canal-otolith interaction. Healthy young (n=30) and healthy older (n=60) subjects were rotated about an earth vertical axis, and about a 30 degree off-vertical axis. Eye movements during and following rotation were recorded using electro-oculography. Results indicated that there were statistically significant changes in the otolith-ocular reflex and semicircular canal-otolith interaction as a function of age. The modulation component during off-vertical axis rotation (OVAR) was greater in the older group compard to the young adults, whereas the bias component was smaller with advanced age. The foreshortening of the vestibulo-ocular reflex time constant induced by post-rotatory head tilt following cessation of rotation was less prominent in the older group. There were no consistent changes in the semicircular canal-ocular reflex. Overall, response parameters showed more variability in the older subjects. We conclude that age related changes in the otolith-ocular reflex and semicircular canal-otolith interaction are a result primarily of a degradation of central vestibular processing of otolith signals rather than a decline of peripheral vestibular function.
Adult↗
Assessment: vestibular testing techniques in adults and children [RETIRED]: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.
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Adult↗
Interlaboratory variability of rotational chair test results II: analysis of simulated data.
Standardization of rotational chair testing across laboratories has not been achieved because of differences in test protocol and analysis algorithms. The Interlaboratory Rotational Chair Study Group was formed to investigate these differences. Its first study demonstrated significant variability in calculated results using actual patient data files. No estimation of accuracy could be made, however, because the "true" values of response parameters were unknown. In this study we used simulated "patient" data files to further explore the differences among analysis algorithms. We found a high degree of agreement and accuracy across laboratories using automated analysis of high signal-to-noise/low-artifact data for gain, phase, and asymmetry. Variability increased significantly for the lower signal-to-noise ratio/higher artifact files. Operator intervention generally improved accuracy and decreased variability, but there were cases in which operator intervention reduced accuracy.
Computer Simulation↗
Short- and long-term outcomes of canalith repositioning for benign paroxysmal positional vertigo.
This is a prospective, nonrandomized study of the canalith repositioning procedure (CRP) for treatment of benign paroxysmal positional vertigo (BPPV). CRP was used to treat 168 patients with BPPV. Patient data were gathered by yearly telephone interviews to determine whether symptoms of position-induced vertigo had returned. After 1 or 2 treatment sessions 91.3% of patients reported complete symptom resolution. Average follow-up for the study population after the initial treatment was 26 months. A recurrence rate of 26.8% was found among those patients who initially reported resolution of symptoms after CRP. Application of recurrence data to a Kaplan-Meier estimation suggests a 15% recurrence rate per year of BPPV, with a 50% recurrence rate of BPPV at 40 months after treatment. There was no significant association between cure or recurrence rate and sex, age, duration of symptoms, presumed cause, or treating physician.
Adolescent↗
Past history of otitis media and balance in four-year-old children.
OBJECTIVES/HYPOTHESIS: To obtain normative data for a population of children 4 years of age with respect to standard vestibular and balance test protocols and to determine, in the absence of concurrent middle ear effusion (MEE), the possible changes caused by a history of recurrent or persistent MEE. STUDY DESIGN: Comparative studies of the results of vestibular and balance tests in a cohort of young children with and without a history of MEE. METHODS: Seventy-one children, 4 years of age, with a well-documented history since early infancy regarding the presence or absence of MEE were evaluated using pneumatic otoscopy, tympanometry, audiometry, and vestibular and balance (rotational and moving platform posturography) tests. For the results of the vestibular and balance tests, comparisons were made between the group of 31 children (43.7%) without and the group of 40 children (56.3%) with a history of recurrent or persistent MEE, when a positive disease history was defined as at least a 10% cumulative percentage of time with MEE between early infancy and time of testing. RESULTS: When compared with children with a negative history of significant MEE, children with a positive history had a lower average gain to a rotational stimulus of 0.1 Hz, 150 degrees/s (0.57 vs. 0.44; P = .007). There were no significant differences between groups with respect to other measures. CONCLUSIONS: These results suggest that a history of recurrent or persistent MEE affects the vestibular and/or balance function of 4-year-old children when tested in the absence of a concurrent episode of MEE. The possible sequelae of the disease should be weighed in future considerations of early intervention for MEE.
Child↗
Physical therapy for migraine-related vestibulopathy and vestibular dysfunction with history of migraine.
OBJECTIVES/HYPOTHESIS: To assess the efficacy of physical therapy for patients with a diagnosis of migraine-related vestibulopathy (MRV) or vestibular dysfunction with a history of migraine headache. STUDY DESIGN: Retrospective case series METHODS: Thirty-nine patients were identified through a retrospective chart review, 14 with a diagnosis of MRV and 25 with migraine headache. The patients were treated with a custom-designed physical therapy exercise program for a mean of 4.9 visits over a mean duration of 4 months. Patients completed the Dizziness Handicap Inventory (DHI), the Activities-Specific Balance Confidence Scale (ABC), and the Dynamic Gait Index (DGI), reported the number of falls they had experienced in the past 4 weeks, and rated the severity of their dizziness on an analogue scale of 0 to 100 at initial evaluation and at discharge. RESULTS: Significant differences were seen before and after therapy in each of the outcome measures used. The average decrease in DHI score was 12 points (P < .01). ABC scores increased an average of 14 points (P < .01). Subjects increased their DGI scores an average of 4 points (P < .01). The number of patients reporting more than one fall decreased by 78% at discharge. (P < .05). Baseline symptoms of dizziness decreased an average of 11 points (P < .05). CONCLUSIONS: Patients with MRV and migraine headache demonstrated improvement in physical performance measures and self-perceived abilities after vestibular physical therapy.
Adult↗
Cervicogenic dizziness: a review of diagnosis and treatment.
The diagnosis of cervicogenic dizziness is characterized by dizziness and dysequilibrium that is associated with neck pain in patients with cervical pathology. The diagnosis and treatment of an individual presenting with cervical spine dysfunction and associated dizziness complaints can be a challenging experience to orthopaedic and vestibular rehabilitation specialists. The purpose of this article is to review the incidence and prevalence, historical background, and proposed pathophysiology underlying cervicogenic dizziness. In addition, we have outlined the diagnostic criteria, evaluation, and treatment of dizziness attributed to disorders of the cervical spine. The diagnosis of cervicogenic dizziness is dependent upon correlating symptoms of imbalance and dizziness with neck pain and excluding other vestibular disorders based on history, examination, and vestibular function tests. When diagnosed correctly, cervicogenic dizziness can be successfully treated using a combination of manual therapy and vestibular rehabilitation. We present 2 cases, of patients diagnosed with cervicogenic dizziness, as an illustration of the clinical decision-making process in regard to this diagnosis.
Cervical Vertebrae↗
Central causes of dizziness.
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Craniocerebral Trauma↗