Biomedical subjects

J M Furman

Publications and source records attributed to J M Furman.

At least 55 records · Page 3Linked to original sources

PubMed1996

Functional outcome of vestibular rehabilitation in patients with abnormal sensory-organization testing.

A goal of vestibular rehabilitation is to improve the functional status of patients with balance disorders. Despite the focus of vestibular rehabilitation on function, few objective data describe the outcome of vestibular rehabilitation in terms of balance function. In this prospective observational study, we tested a well-defined patient cohort (n = 67) with abnormal pretreatment sensory-organization testing who were undergoing vestibular rehabilitation. Patient outcomes were determined by using objective and subjective measures of function before and after rehabilitation. Overall, 60% of patients showed objective improvement of balance function; 25% of patients improved to normal. Analysis of success and failure of vestibular rehabilitation is important as an aid to appropriate patient counseling and efficient use of rehabilitation resources.

Adult↗

PubMed1995

Time-frequency analysis of postural sway.

Postural sway during quiet stance has been used to characterize the postural control system. Most studies have used center of pressure (COP) measurements and have assumed stationarity, however, recent research has indicated that COP is not stationary. The purpose of this study is to introduce and demonstrate a nonstationary spectral estimation technique to examine the time-varying nature of postural sway. Data from two experiments were used to verify the usefulness of the spectral estimator for the analysis of COP. The first data set contains COP recorded from normal subjects swaying about their ankles in response to a metronome as it was gradually changed from 2 to 1 Hz. The time-frequency distribution reveals time-varying spectral changes corresponding to frequency changes made by the subjects. The second set consists of COP from normal subjects and vestibularly impaired patients standing quietly on a force plate with eyes closed for 100 s. The time-frequency distributions for the COP were estimated for both sets of data. The COP's appear to be nonstationary with the energies at a given frequency modulating through time.

Computer Simulation↗

PubMed1995

Role of posturography in the management of vestibular patients.

Computerized dynamic posturography uses a force platform that can both translate and rotate. When combined with visual stimuli, it can be used to determine the relative importance of the various sensory inputs critical for balance, namely vision, somatosensation, and vestibular sensation. Studies to date have shown several patterns of abnormalities on posturography, the best recognized being the vestibular pattern. Many patients with a high suspicion of having a peripheral vestibular abnormality (based on other information) have such a pattern. Moreover, few normal subjects have such abnormalities. Although computerized dynamic posturography does not help in localizing a lesion or determining its etiology, such testing does provide a functional measure that can be helpful in understanding a patient's ability to properly use vestibular system information. Posturography is helpful in the management of patients with suspected vestibular disorders. In addition to suggesting the presence of a vestibular system abnormality, particularly an uncompensated peripheral vestibular deficit, a bilateral peripheral vestibular deficit, or a central vestibular abnormality, computerized dynamic posturography may help guide the clinician regarding choice of treatment and counseling of patients. Further studies are required to determine the ultimate role of computerized dynamic posturography in the management of patients with vestibular disorders.

Humans↗

PubMed1995

Effect of otitis media on the vestibular system in children.

Forty-one children with otitis media (OM) were evaluated by moving platform posturography (Equitest, NeuroCom) before and after insertion of tympanostomy tubes, and were compared to children with no ear disease (N = 50). Velocity of sway increased with increasing difficulty of test conditions (I-VI) for both groups of children (p < .001), and children less than 7 years of age had a higher velocity than children 7 years old or older (p < .001). Children with OM had a higher velocity than normal children (p < .05). For children tested less than 30 days after insertion of tympanostomy tubes, the velocity for condition VI was significantly lower than before insertion (p < .05). Also, that the 6 children who had fallen on all trials on condition V or VI were able to stand on these trials after insertion of tympanostomy tubes indicates an improvement. These findings indicate that episodes of OM may affect balance, leaving children more clumsy and accident-prone, and possibly impairing motor development.

Adolescent↗

PubMed1995

A practical work-up for vertigo.

Specific elements in the history and physical examination direct the work-up of the "dizzy" patient toward or away from a vestibular disorder. When a disorder of this type is suspected, the differential diagnosis includes benign positional vertigo, vestibular neuritis, vertebrobasilar insufficiency, migraine, and endolymphatic hydrops, which is the pathologic condition thought to underlie Meniere's disease. Anxiety is well recognized as a potential component of vestibular abnormalities or as the primary problem.

Humans↗

PubMed1994

Panic in otolaryngology patients presenting with dizziness or hearing loss.

This study compared 50 patients presenting to an otolaryngology clinic with a complaint of dizziness and 50 patients presenting with hearing loss on questionnaire measures of panic, phobic avoidance, generalized anxiety, and depression. Clinical and laboratory evaluations of vestibular and audiological complaints were also completed. Twenty percent of the group with dizziness and none of the group with hearing loss reported symptoms that met DSM-III-R criteria for panic disorder. Patients with dizziness and peripheral vestibulopathy had more symptoms of phobic avoidance, generalized anxiety, and depression than patients with confirmed hearing loss.

Adult↗

PubMed1994

Interlaboratory variability of rotational chair test results. Interlaboratory Rotational Chair Study Group.

Test-retest reliability of rotational chair testing for a single facility has previously been examined by others. The actual data analysis methods, however, have received far less attention. The variety of both hardware and software currently used theoretically may affect the results for a given subject tested at different facilities. The purposes of this study were, first, to quantify the amount of variability in the analysis of identical raw data files at multiple rotational chair testing facilities by using automated analysis; second, to evaluate the effect of operator intervention on the analysis; and third, to identify possible sources of variability. Raw data were collected from 10 normal subjects at 0.05 Hz and 0.5 Hz (50 degrees per second peak velocity). Diskettes containing raw electro-oculogram data files were then distributed to eight participating laboratories for analysis by two methods: (1) using automated analysis algorithms and (2) using the same algorithms but allowing operator intervention into the analysis. Response parameters calculated were gain and phase (re: velocity). The SD of gain values per subject for automated analysis ranged from 0.01 to 0.32 gain units and of phase values from 0.4 to 13.7 degrees. For analysis with operator intervention, the SD of gain values ranged from 0.02 to 0.10 gain units and of phase values from 0.4 to 4.4 degrees. The difference between automated analysis and analysis with operator intervention was significant for gain calculations (p < 0.02) but not for phase calculations (p > 0.05). This study demonstrates significant variability in automated analysis of rotational chair raw data for gain and phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Posturography: uses and limitations.

The field of posturography has been advanced by the development of computerized dynamic posturography, wherein a force platform has been combined with visual stimuli as a means of determining the relative importance of the various sensory inputs critical for balance, namely vision, somatosensation and vestibular sensation. When compared with other tests currently available for the assessment of vestibular function, computerized dynamic posturography is unique in that it assesses 'balance' rather than attempting to assess peripheral or central vestibular function more directly. This discussion focuses on the device manufactured by NeuroCom International, marketed under the trade name Equitest. The sensory organization portion of the test has been shown to be most useful in the assessment of patients with suspected vestibular disorders. This chapter reviews the current status of computerized dynamic posturography based on published material. The vestibular pattern on computerized dynamic posturography has been observed in patients with ongoing vestibulospinal deficits. Another pattern has been labelled 'surface dependence' or 'combined visual-vestibular deficit'. Data suggest that 2-3 weeks after loss of unilateral peripheral vestibular function, most patients lose their vestibular pattern. Thus, posturography can provide valuable information regarding the status of compensation for a peripheral vestibular deficit. Results from computerized dynamic posturography may disagree with those from other vestibular laboratory testing, which suggests that posturography tests a different aspect of vestibular function than that assessed by electronystagmography and rotational testing. Computerized dynamic posturography does not provide localizing or lateralizing information, nor any information regarding aetiology; it does provide functional information regarding how well an individual can use their balance and an indication of the importance of a patient's balance disturbance on their activities of daily living. Also, computerized dynamic posturography provides a functional measure that is helpful in predicting the benefit that patients may expect to receive from therapeutic intervention with physical therapy.

Humans↗

PubMed1993

Genetic heterogeneity of Usher syndrome type II.

Usher syndrome is an autosomal recessive disorder characterised by retinitis pigmentosa and congenital sensorineural hearing loss. A gene for Usher syndrome type II (USH2) has been localised to chromosome 1q32-q41. DNA from a family with four of seven sibs affected with clinical characteristics of Usher syndrome type II was genotyped using markers spanning the 1q32-1q41 region. These included D1S70 and D1S81, which are believed to flank USH2. Genotypic results and subsequent linkage analysis indicated non-linkage of this family to these markers. The A test analysis for heterogeneity with this family and 32 other Usher type II families was statistically significant at p < 0.05. Further clinical evaluation of this family was done in light of the linkage results to determine if any phenotypic characteristics would allow for clinical identification of the unlinked type. No clear phenotypic differences were observed; however, this unlinked family may represent a previously unreported subtype of Usher type II characterised by a milder form of retinitis pigmentosa and mild vestibular abnormalities. Heterogeneity of Usher syndrome type II complicates efforts to isolate and clone Usher syndrome genes using linkage analysis and limits the use of DNA markers in early detection of Usher type II.

Adolescent↗

PubMed1993

Off-vertical axis rotational responses in patients with unilateral peripheral vestibular lesions.

Off-vertical axis rotation (OVAR) stimulates the otolith organs in a manner that is suitable for assessment of the otolith-ocular reflex. To further assess the potential clinical usefulness of OVAR, the eye movement responses of seven patients with surgically confirmed unilateral peripheral vestibular lesions were compared with the eye movement responses of a group of age-matched, healthy, asymptomatic control subjects. Patients and controls were tested with constant velocity rotations that followed a brief period of angular acceleration (velocity trapezoid) using either earth-vertical axis (EVA) rotation or OVAR. Both EVA and OVAR sinusoidal velocity profiles were also performed. Results indicated that each patient had 1) an asymmetric OVAR response, ie, a bias component whose direction was opposite normal when rotating toward the lesioned ear, and 2) a normal modulation component. Population data suggested that patients had 1) a more rapid decay of response than normal subjects during OVAR velocity trapezoids, 2) an increased phase lead as compared to normal subjects during sinusoidal OVAR, and 3) like normal subjects, a less rapid decay of response during OVAR velocity trapezoids than during EVA rotational velocity trapezoids. Taken together, these findings suggest that patients with unilateral peripheral vestibular deficits have abnormal otolith-ocular and semicircular canal-ocular reflexes but that a single labyrinth appears to provide an otolithic signal sufficient for qualitatively normal semicircular canal-otolith interaction.

Adult↗

PubMed1993

Jongkees' formula re-evaluated: order effects in the response to alternate binaural bithermal caloric stimulation using closed-loop irrigation.

Normal limits for the response to caloric irrigation typically are specified as percentage of reduced vestibular response (RVR) and directional preponderance (DP). These measures are calculated using Jongkees' formula without regard to which ear is stimulated first. To assess the influence of the order in which the caloric stimuli are delivered we reviewed the responses to closed loop caloric irrigation of two groups of normal subjects and a group of unselected patients. Results indicated a consistent declining trend in response from the first caloric administration to the last administration in all groups and subgroups except in male patients over 60 years of age. Consequently, a significant bias in RVR was observed. Specifically, with the order of irrigation left cold, right cold, left warm, right warm, the mean percentage RVR for both the patients and control subjects was about a 5% right RVR. The bias resulted in right-sided unilateral hypofunction being diagnosed 2.4 times more often than left-sided hypofunction in patients aged 16-59. Our results differ from the previous literature that describes the effect of order on the response to caloric irrigation; this discrepancy may be related to our use of a closed-loop system for caloric irrigation. We conclude that vestibular laboratories should account for the effect of order in their patients' responses to caloric stimulation. We offer suggestions on how Jongkees' formula can be corrected for the effect of order.

Adolescent↗

PubMed1992

Otolith-ocular testing in human subjects.

Assessment of the otolith-ocular reflex of human subjects involves linear acceleration and/or changes in the orientation of the head with respect to gravity. Several such stimuli are currently under investigation regarding their applicability to the evaluation of patients with dizziness and balance disorders. Discussed in this paper are off-vertical axis rotation, eccentric rotation, pitch and roll rotation, and linear acceleration. For each of these stimuli, basic principles, normative human data, and patient data are described. Although none of these methods are currently established for clinical use, each of them, especially off-vertical axis rotation and linear acceleration, have the potential for developing into a clinically useful method for assessing otolith function in man.

Electrooculography↗

PubMed1992

Off-vertical axis rotation: a test of the otolith-ocular reflex.

The vestibulo-ocular reflex was studied via off-vertical axis rotation (OVAR) in the dark. The axis of the turntable could be tilted from vertical by up to 30 degrees. Eye movements were measured with electro-oculography. Results from healthy asymptomatic subjects indicated that 1) a reliable otolith-induced response could be obtained during constant velocity OVAR using a velocity of 60 degrees/s with a tilt of 30 degrees; 2) constant velocity OVAR rotation was nausea-producing and, especially if subjects were rotated in the dark about an earth-vertical axis prior to being tilted, disorienting; and 3) sinusoidal OVAR produced minimal nausea; the eye movement response appeared to be the result of a combination of semicircular canal and otolith components. We conclude that OVAR has the potential of becoming a useful method for clinically assessing both the otolith-ocular reflex and semicircular canal-otolith interaction.

Adult↗

PubMed1992

Plasticity of the human otolith-ocular reflex.

The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

Adaptation, Physiological↗

PubMed1991

Asymmetrical ocular pursuit with posterior fossa tumors.

We report two patients with posterior fossa neoplasms who demonstrated asymmetrically impaired horizontal ocular pursuit documented with electrooculography. One patient had impaired pursuit contralateral to a pontomedullary lesion, whereas the second patient had impaired pursuit ipsilateral to a pontocerebellar lesion. These patients demonstrate that posterior fossa lesions may impair ocular pursuit either contralaterally or ipsilaterally unlike cerebral hemispheric lesions, which impair ocular pursuit ipsilaterally or bilaterally.

Adenocarcinoma↗

PubMed1991

Familial sensorineural hearing loss: a correlative study of audiologic, radiographic, and vestibular findings.

A multidisciplinary approach to the study of a family with autosomal dominant sensorineural hearing loss is presented. The affected family members underwent extensive clinical and laboratory evaluation. They were found to have various degrees of bilateral congenital inner ear anomalies as imaged by computed tomography. The degree of structural abnormalities in the inner ears correlated with the severity of hearing impairment. Vestibular testing revealed nonspecific abnormalities generally correlating with audiologic and radiographic findings. This report presents a unique form of sensorineural hearing loss not previously described and is the first in-depth clinical study of nonsyndromal "Mondini dysplasia" occurring in a family.

Adult↗

PubMed1990

Epileptic nystagmus.

We report a 52-year-old woman with episodes of vertigo accompanied by right beating nystagmus and left posterior temporoparietal sharp waves and spikes on electroencephalogram without change in level of consciousness. Electrooculography demonstrated that the episodes of nystagmus were not preceded by gaze deviation and that nystagmus slow component velocities were linear. This patient's epileptic nystagmus may have been the result of excitation of cerebral ocular pursuit pathways.

Electroencephalography↗

PubMed1990

Characteristics of the memory loss of a patient with Wernicke-Korsakoff's syndrome without alcoholism.

The memory loss in alcoholic Wernicke-Korsakoff syndrome has been well characterized. However, it has been suggested that some of the neuropsychological defects seen in these patients are due to frontal lobe dysfunction resulting from chronic alcohol abuse. The present report details the nature and extent of the amnesia in a Wernicke-Korsakoff patient who did not have a history of alcoholism. In spite of her normal performance on measures of frontal lobe function, this patient showed many characteristics similar to those seen in alcoholic Wernicke-Korsakoff syndrome including a graded loss of remote memories and abnormal semantic information processing. Thus, the extent of the "core" features of this amnesic syndrome may be greater than was previously thought.

Alcohol Amnestic Disorder↗