| 1. |
- Ledin, Torbjörn, et al.
(författare)
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Chronic toxic encephalopathy investigated using dynamic posturography
- 1991
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Ingår i: American Journal of Otolaryngology. - 0196-0709 .- 1532-818X. ; 12:2, s. 96-100
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Tidskriftsartikel (refereegranskat)abstract
- Seven male patients previously exposed to industrial solvents and diagnosed with chronic toxic encephalopathy (aged 38 to 69 years; mean age, 56 years) were investigated by dynamic posturography and compared with healthy, age-matched male control patients. Dynamic posturography comprises two phases: a sensory organization (SO) phase, in which the support surface and visual surround are either stable or referenced to the patient's sway, with eyes open or closed, and a movement coordination (MC) phase, in which the platform makes active movements. In SO testing, the patient group showed significantly impaired equilibrium performance compared with the control group in most test conditions. The MC test revealed no differences between groups. A relationship was found between the equilibrium score resulting from SO testing with stable support and visual surround and the sway area of the confidence ellipse elicited 3 years previously by static posturography with eyes open. We conclude that patients with chronic toxic encephalopathy have impaired equilibrium, as demonstrated by dynamic posturography testing.
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| 2. |
- Ledin, Torbjörn, 1962-
(författare)
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Dynamic posturography in evaluating human equilibrium
- 1991
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Equilibrium assessment by means of posturography can be performed ina dynamic fashion, meaning that the environment does not remainstable during the test. In the EquiTest dynamic posturography version, the support surface and the visual surround are movable, actively or in response to body movements. Equilibrium ability is investigated in a sensory organ1zat1on (SO) part where six different combinations of vision (normal, sway referenced and absent) and support surface conditions (stable and sway referenced) are given. Postural responses to sudden translations and tiltings of the support surface are investigated in a movement coordination (MC) part. standardized dynamic posturography was utilized to assess equilibrium performance in different groups of subjects. In twentynine elderly healthy subjects, dynamic posturography evaluated the influence of age on equilibrium parameters. A decline compared to younger age groups was f~und. Fifteen of the elde:ly s~bjects underwent physical exerc~ses two hours a week dur~ng n~ne weeks, the remaining subjects served as controls. Significant improvement attributable to the exercises was found in one out of six so conditions and two out of twelve clinical equilibrium tests. In twenty-eight subjects with polyneuropathy, impaired equilibrium was found in so and delayed reactions to sudden support surface movements -w~re found in MC. Comparing dynamic posturography with neurological measures of polyneuropathy unveiled correlations between subjective clinical scoring and latencies to forward translations in MC and to equilibrium performance in three out of six so conditions. In seven subjects with chronic toxic encephalopathy due to industrial solvent exposure, impaired equilibrium was found in four out of six so conditions, although MC was normal. In thirteen healthy subjects, acute low level alcohol ingestion caused balance disturbances in SO conditions with abs7nt visual cues. In addition to disturbances of ocular smooth pursu1t and visual suppression of the vestibuloocular reflex in elevenabstinent chronic alcoholics, deteriorated equilibrium performance was found in four so tests out of six. Postural reactions to both sudden translations and tiltings of the support surface were found to be marred, in spite of normal nerve conduction velocities. The EquiTest dynamic posturography apparatus was cont:olle~ by amenu-driven interface constructed at the department, ~n wh~ch the user may expose the subject to arbitrary movement~ ~f the.supp~rt surface and the visual surround. The effects of v1s1on, d~rect~on and amplitude on postural reactions to su~den support surface translations were evaluated. Absence of v1sual cues caused more rapid correction maneuvres, but the translation direction did ~ot influence the reactions. Postural responses reflected translat1on amplitudes.
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| 3. |
- Möller, Claes, 1950-, et al.
(författare)
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Otoneurological findings in workers exposed to styrene
- 1990
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 16:3, s. 189-194
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Tidskriftsartikel (refereegranskat)abstract
- An otoneurological test battery was administered to 18 workers with long-term exposure (6-15 years) to styrene at levels well below the current Swedish limit (110 mg/m3). The results were compared with those of a reference group. Disturbances were found in the central auditory pathways of seven workers. Tests reflecting central processing of impulses from different sensory equilibrium organs were abnormal for 16 workers. The most relevant tests seemed to be static posturography and the rotatory visual suppression test. In the posturography the styrene group had a significantly larger sway area than the reference group. In the visual suppression test, the styrene workers displayed a significantly poorer ability to suppress vestibular nystagmus than the reference group. It was concluded that styrene exposure in industrial environments at moderate or low levels causes central nervous system disturbances which are not always diagnosable with psychometric tests but can be apparent in special otoneurological tests.
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| 4. |
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| 5. |
- Vrethem, Magnus, et al.
(författare)
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Correlation between dynamic posturography, clinical investigation, and neurography in patients with polyneuropathy
- 1991
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Ingår i: Journal for Oto-Rhino-Laryngology. - : S. Karger AG. - 0301-1569 .- 1423-0275. ; 53:5, s. 294-298
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic posturography (PG) is a new objective method to study functional performance in diseases affecting balance. It measures muscle response latencies and sway angles to standardized alterations of a moveable platform and moveable surroundings. Twenty-eight patients with polyneuropathy (PN) were studied by clinical investigation, vibrametry, neurography, and dynamic PG. The results of dynamic PG and vibrametry were compared with those of 29 healthy controls. In the patients with PN, clinical scores correlated to the latencies of the muscle response when the platform was suddenly moved forward, and to equilibrium performance (sway angles) in dynamic PG test conditions with eyes closed and the platform either stable or ‘sway-referenced’. That is, the platform moves in response to the patient’s anterior-posterior sway, creating a disturbed proprioceptive input to the brain. Clinical scores also correlated to the equilibrium performance when both platform and surroundings were sway-referenced. In conclusion dynamic PG, in addition to clinical investigations and neurophysiology, is a valuable and objective method for estimating the equilibrium performance in patients with PN.
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| 6. |
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