Stephen W. Parker

Vertigo of Delayed Onset after Sudden Deafness

An entity of episodic true vertigo of delayed onset following sudden and profound sensorineural hearing loss is described. Data on 12 patients and three case reports are presented. The latency between sudden deafness and the onset of the vertigo varied from 1 to 68 years. The vestibular symptoms are identical to the vestibular symptoms of Ménières disease, and there is some evidence that endolymphatic hydrops in the previously deafened ear represents at least part of the labyrinthine pathology. Labyrinthectomy in the deaf ear was curative. Tentatively, this entity is best considered a variant of Ménières disease.

Can Tai Chi improve vestibulopathic postural control

OBJECTIVES To evaluate the rationale and scientific support for Tai Chi as an intervention for vestibulopathy and to offer recommendations for future studies. DATA SOURCES A computer-aided search, including MEDLINE and Science Citation Index, to identify original Tai Chi studies published in English; relevant references cited in the retrieved articles were also included. STUDY SELECTION A preliminary screening selected all randomized controlled trials (RCTs), non-RCTs, case-control studies, and case series that included Tai Chi as an intervention and had at least 1 outcome variable relevant to postural stability. DATA EXTRACTION Authors critically reviewed studies and summarized study designs and outcomes in a summary table. DATA SYNTHESIS Twenty-four Tai Chi studies met screening criteria. No studies specifically studying Tai Chi for vestibulopathy were found. Collectively, the 24 studies provide sometimes contradictory but generally supportive evidence that Tai Chi may have beneficial effects for balance and postural impairments, especially those associated with aging. Ten RCTs were found, of which 8 provide support that Tai Chi practiced alone, or in combination with other therapies, can reduce risk of falls, and/or impact factors associated with postural control, including improved balance and dynamic stability, increased musculoskeletal strength and flexibility, improved performance of activities of daily living (ADLs), reduced fear of falling, and general improvement in psychologic well-being. Studies using other designs support the results observed in RCTs. CONCLUSIONS At present, few data exist to support the contention that Tai Chi specifically targets the impairments, functional limitations, disability, and quality of life associated with peripheral vestibulopathy. There are, however, compelling reasons to further investigate Tai Chi for vestibulopathy, in part because Tai Chi appears useful for a variety of nonvestibulopathy etiologic balance disorders, and is safe. Especially needed are studies that integrate measures of balance relevant to ADLs with other psychologic and cognitive measures; these might help identify specific mechanisms whereby Tai Chi can remedy balance disorders.

Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: Preliminary report

BackgroundVestibular rehabilitation (VR) is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC), have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two different therapies are unknown.MethodsWe examined the relationship between lower extremity neuromuscular function and trunk control in 36 older adults with vestibulopathy, randomized to 10 weeks of either VR or TC exercise. Time-distance measures (gait speed, step length, stance duration and step width), lower extremity sagittal plane mechanical energy expenditures (MEE), and trunk sagittal and frontal plane kinematics (peak and range of linear and angular velocity), were measured.ResultsAlthough gait time-distance measures were improved in both groups following treatment, no significant between-groups differences were observed for the MEE and trunk kinematic measures. Significant within groups changes, however, were observed. The TC group significantly increased ankle MEE contribution and decreased hip MEE contribution to total leg MEE, while no significant changes were found within the VR group. The TC group exhibited a positive relationship between change in leg MEE and change in trunk velocity peak and range, while the VR group exhibited a negative relationship.ConclusionGait function improved in both groups consistent with expectations of the interventions. Differences in each groups response to therapy appear to suggest that improved gait function may be due to different neuromuscular adaptations resulting from the different interventions. The TC groups improvements were associated with reorganized lower extremity neuromuscular patterns, which appear to promote a faster gait and reduced excessive hip compensation. The VR groups improvements, however, were not the result of lower extremity neuromuscular pattern changes. Lower-extremity MEE increases corresponded to attenuated forward trunk linear and angular movement in the VR group, suggesting better control of upper body motion to minimize loss of balance. These data support a growing body of evidence that Tai Chi may be a valuable complementary treatment for vestibular disorders.

Vestibular rehabilitation: Useful but not universally so ☆

OBJECTIVE: Although vestibular rehabilitation (VR) is gaining popularity, few data support its utility in improving locomotor stability, and no good predictors exist of whom will benefit most. STUDY DESIGN AND SETTING: A double-blind, placebo-controlled randomized trial of vestibular rehabilitation was conducted at a large tertiary care hospital on 124 patients (59 ± 18 years old) with unilateral (n = 51) or bilateral (n = 73) vestibular hypofunction, of whom 86 completed a 12-week intervention. Of these 86, 27 returned for long-term (1-year) follow-up testing. The primary outcome measure was locomotor stability. RESULTS: Group A (6 weeks of VR) significantly (P < 0.01) increased their gait velocity and stability compared with group B (6 weeks of strengthening exercise), but there was a smaller difference (P = 0.05) between groups at 12 weeks, when both had had VR; there were no group differences at 1 year. Of the 86 who completed the intervention, 52 (61%) had clear locomotor gains. CONCLUSION AND SIGNIFICANCE: VR is helpful for most patients in providing locomotor stability, but further work is needed to determine the factors that prevent VR from being effective for all patients with vestibulopathy.

Effect of mesencephalic lesions on feeding behavior in rats.

Abstract Large bilateral lesions in the mesencephalic reticular formation of rats led to severe aphagia and adipsia. Smaller bilateral mesencephalic lesions in the midreticular formation, between the red nucleus and aqueduct in the dorsoventral axis, were most effective in producing alterations in feeding behavior. Lesions restricted to the extreme lateral reticular formation, tectum, central gray matter or substantia nigra had little or no effect on food and water intake. Hyperphagia was observed in one rat with lesions caudal to the red nucleus at the edges of the central gray matter. The syndrome following small mesencephalic lesions was similar to the aphagicadipsic syndrome following lateral hypothalamic damage; most animals recovered within 1 or 2 weeks. Both direct current and radio-frequency current were effective in producing the syndrome. Neurological and behavioral symptoms, other than those related to food and water intake, were transitory.

Broad-band visual capacities are not selectively impaired in Alzheimer's disease.

Histological examination of the optic nerves of Alzheimers disease (AD) patients has revealed a selective degeneration of large axon ganglion cells. This morphological abnormality raises the possibility of a selective impairment of broad-band channel visual function. To test this hypothesis, we administered visual psychophysical tests associated with either the color-opponent or the broad-band retinocortical channel to 14 AD patients and 29 elderly control subjects (ECS). In previous studies in monkeys, these tests had been sensitive to the effects of either parvocellular or magnocellular LGN lesions. In the present study, the color-opponent channel was assessed by tests of texture and color discrimination; the broad-band channel was assessed by tests of flicker and motion detection. Logistic regression analysis indicated that all tests collectively discriminated diagnostic groups at a borderline level of significance (p = 0.09). ANOVA also indicated a trend towards overall depressed function for AD patients on some capacities tested. Analyses comparing the prevalence of deficits in the AD and ECS groups showed that a significantly greater number of AD patients than ECS had deficits on texture discrimination, blue-violet discrimination, and 4.72 degrees/s motion detection. No individual subject demonstrated a selective impairment of broad-band channel function. The visual deficits in AD did not resemble those caused by lesions of magnocellular LGN in monkeys, indicating that the visual impairment in AD is not a functional reflection of damage limited to the broad-band channel.(ABSTRACT TRUNCATED AT 250 WORDS)

Computed Tomography of Acoustic Neuroma

Review of computed tomographic (CT) scans of 49 consecutive patients with surgically excised acoustic neuromas revealed positive scans in 80% following contrast enhancement, with 20% false negative scans. All tumors over 2 cm in diameter were shown by optimal scans with contrast enhancement. The positive scans were evaluated to determine the accuracy of the size of the lesions as predicted by the scan. A radiological approach to the evaluation of suspected acoustic neuromas is suggested.

Cerebellopontine angle meningiomas: clinical manifestations and diagnosis.

Cerebellopontine angle (CPA) meningiomas constitute about 1% of intracranial meningiomas. The clinical aspects of a series of 32 patients with surgically confirmed CPA meningiomas are analyzed. The most common symptoms at the time of the initial evaluation were from the eighth cranial nerve (unilateral hearing loss — 24 patients, vertigo or imbalance — 19 patients, tinnitus — 11 patients), and the fifth cranial nerve (altered sensation — 9 patients, facial pain — 5 patients). On examination, the most common findings were absent caloric response (19 patients), nystagmus (16 patients), diminished facial sensation (14 patients), ataxia (13 patients), reduced hearing (9 patients), and facial weakness (9 patients). There was often a long interval from the onset of symptoms to the correct diagnosis of a tumor. Brain stem auditory evoked potentials, blink reflex testing, posterior fossa myelography, computerized tomographic scanning, and angiography were abnormal in all patients in whom the test was done, but all tests were not performed on all patients. Computerized tomographic scanning and angiography are important for definitive diagnosis and for planning surgical treatment. The histopathology of the temporal bone was studied in three patients with meningiomas in the region of the internal auditory meatus.

Vestibular evaluation--electronystagmography, rotational testing, and posturography.

This report describes a battery of tests that is utilized by several clinical laboratories to investigate vestibular and balance function. The electronystagmogram evaluates eye movements, inner ear function, brainstem function and cerebellar function. Sinusoidal vertical axis rotation is a sensitive measure of horizontal semicircular canal function that is often complimentary to the caloric stimulation portion of the electronystagmogram. Visual-vestibular interaction rotation testing is designed to evaluate brainstem, cerebellar and oculomotor function. Dynamic posturography facilitates measurement of standing balance and permits a quantification of the role of proprioception, vision and the vestibular system in the maintenance of standing balance.

A Double-Blind, Placebo-Controlled Study of Oral Acyclovir in Postherpetic Neuralgia

Twenty-one patients with postherpetic neuralgia of two- to 84-months duration participated in a double-blind, placebo-controlled study of oral acyclovir. Pain perception was assessed with the Melzack Pain Questionnaire at baseline and at two-to six-week intervals during the ensuing six months. Clinically significant pain reduction occurred in eight patients: four received acyclovir, and four received a placebo. Several treatment strategies have been advocated for relief of postherpetic neuralgia. Results of the present study demonstrate the need for a double-blind, placebo-controlled paradigm to substantiate the efficacy of new clinical approaches. The same caveat applies to the more common syndromes encountered in psychiatric practice.