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Biomedical subjects

Måns Magnusson

Publications and source records attributed to Måns Magnusson.

12 recordsLinked to original sources
PubMed2006

Primary and coupled cervical movements: the effect of age, gender, and body mass index. A 3-dimensional movement analysis of a population without symptoms of neck disorders.

STUDY DESIGN: Exploratory experimental design. OBJECTIVES: To examine primary and coupled cervical movements, and to study the effects of age, gender, and body mass index in a "neck-healthy" population. These data could serve as a basis for future interventions and to assess normal variations. SUMMARY OF BACKGROUND DATA: Cervical movements are biomechanically and neurophysiologically complex. Neck disorders and trauma most often influence cervical movements. With 3-dimensional recordings, it is possible to make precise, noninvasive evaluations of how the head moves on the stable trunk, and to analyze primary and coupled movements. METHODS: A total of 120 subjects (60 men and 60 women, ages 20-79), were tested with Zebris (Zebris Medizintechnik GmbH, Isny, Germany), a 3-dimensional movement analyzer. RESULTS: Age influences the majority of primary and coupled movements. With increasing age, primary movement size decreases in all cardinal planes. Age most strongly affects the coupled movements of primary rotation and lateral flexion. Gender and body mass index have only slight influences. CONCLUSIONS: Coupled movements are a natural part of cervical motion together with primary movements and follow specific patterns in subjects with no symptoms of neck disorders. Our study shows that cervical motion alters throughout life according to specific patterns but with individual variations.

Adult↗
PubMed2005

Older patients with distal forearm fracture. A challenge to future fall and fracture prevention.

BACKGROUND AND AIMS: Falls and fractures in older people are a common health problem. Patients with distal forearm fracture are at risk of sustaining new fractures. The aim of this work was to describe the characteristics of this patient group. METHODS: Sixty women and six men, mean age 68 years (50-86), with a recent fall-related distal forearm fracture, filled in a questionnaire about medical history, previous falls and fractures. Handgrip strength on the non-fractured side, one-leg standing, walking tests, and test of vibration sensation were measured and a video-nystagmoscopy was performed. RESULTS: One-third of the subjects had fallen during the last year, and one-third had had previous fall-related fractures during the last 10 years. Half of the patients took medication and were examined for chronic ailments regularly. Handgrip strength, balance and walking capacity declined with age and were similar to reference values. In three patients, the vibration sensation value was above the threshold value. Fifty patients (76%) had nystagmus, but no relationship between fall direction, physical performance and nystagmus was found. CONCLUSIONS: Although apparently healthy, many patients exhibited risk factors for new falls and fractures. Our recommendation is that these patients should be screened for fall and fracture risk and be targeted for preventive measures, besides fracture treatment. Physical therapists must play a major role in increasing and maintaining general physical functions in this patient group.

Accidental Falls↗
PubMed2005

Posturography can be used to screen for primary orthostatic tremor, a rare cause of dizziness.

OBJECTIVE: Primary orthostatic tremor is a rare neurologic condition of unknown origin characterized by a 10- to 20-Hz tremor in the legs while standing. Patients with primary orthostatic tremor usually complain of dizziness and unsteadiness that is relieved if they sit down or start to walk around. These patients might be referred to neurotology clinics. Previously, the only way to make the diagnosis has been by means of surface electromyographic recordings from the lower limbs during standing. The authors wanted to study whether posturography can be used to screen for primary orthostatic tremor. STUDY DESIGN: Retrospective case review. SETTING: Balance clinic at a tertiary referral center. PATIENTS: From September 2000 to August 2002, 701 patients were investigated at the authors' balance clinic. INTERVENTION: Static posturography on a force platform with 50-Hz sampling frequency. Recordings were made during 120 seconds of quiescent stance with open or closed eyes. MAIN OUTCOME MEASURE: Fast-Fourier transformation (FFT) analysis of recorded torque in the fore-to-aft direction to quantify the spectral power distribution in the range of 0 to 25 Hz. Visual inspection of power spectrum plots was performed. RESULTS: Five patients (0.7%) were identified (1 man and 4 women; mean age, 56 yr; age range, 36-73 yr) with narrow peaks at 8.5 to 18 Hz in the power spectra of their posturographic recordings. Surface electromyographic recordings during standing confirmed their diagnosis of primary orthostatic tremor. CONCLUSION: Analysis of power spectra from posturographic recordings is a simple, quick method to screen for primary orthostatic tremor. The condition might be more common than previously assumed. It is important to identify patients with primary orthostatic tremor because they might be misdiagnosed and left without treatment.

Adult↗
PubMed2004

An office procedure to detect vestibular loss in children with hearing impairment.

As coexisting vestibular and cochlear lesions are of etiological importance, evaluation of children with congenital or early acquired hearing impairment (HI) should include vestibular assessment. A rotation test requires specific equipment and allows only detection of bilateral vestibular impairment. An impulse or head thrust test allows assessment of one ear at a time, detects more pronounced caloric side differences and can be performed without any equipment. We report a consecutive series of children with profound sensorineural HI investigated at a tertiary hospital unit. Age at taking first steps without help, the results of temporal bone images (CT/MRT) and vestibular tests were collected retrospectively from patient files. The children were 12 to 90 months old at the time they attended both a rotation and an impulse test. All 14 children cooperated in the impulse test, and 12 completed the vestibular rotation test successfully. Three out of 14 children tested so far have been confirmed to have a bilaterally pathological vestibulo-ocular reflex confirmed both in the rotation test and the impulse test. Our results show that both the rotation test and the vestibular impulse test can be successfully performed on small children at a regular outpatient appointment.

Age Factors↗
PubMed2004

Acute vestibular neuritis visualized by 3-T magnetic resonance imaging with high-dose gadolinium.

Sudden idiopathic unilateral loss of vestibular function without other signs or symptoms is called acute vestibular neuritis. It has been suggested that reactivation of human herpes simplex virus 1 could cause vestibular neuritis, Bell palsy, and sudden unilateral hearing loss. Enhancement of the facial nerve on gadolinium-enhanced magnetic resonance imaging (MRI) is a common finding in Bell palsy, but enhancement of the vestibular nerve has never been reported in acute vestibular neuritis. We present 2 consecutive cases of acute vestibular neuritis where high-field-strength MRI (3.0 T) with high-dose (0.3 mmol/kg of body weight) gadolinium-pentetic acid showed isolated enhancement of the vestibular nerve on the affected side only. These findings support the hypothesis of a viral and inflammatory cause of acute vestibular neuritis and might have implications for its treatment.

Aged↗
PubMed2004

Idiosyncratic compensation of the subjective visual horizontal and vertical in 60 patients after unilateral vestibular deafferentation.

OBJECTIVE: To investigate long-term compensation mechanisms of utricular function after translabyrinthine surgery for vestibular schwannoma. Correlations between the subjective visual horizontal (SVH) and subjective visual vertical (SVV) and other parameters of vestibular compensation were studied. The correlation between the SVH and SVV was also investigated to see whether these measurements are compatible for patients. MATERIAL AND METHODS: Sixty consecutive patients were investigated 3 months before and 6 months after surgery by means of electronystagmography and SVH and SVV tests. Tumor size was measured using MRI. RESULTS: The SVH and SVV increased significantly towards the ipsilesional side postoperatively. Preoperative tilt correlated with age. Postoperative tilt correlated weakly with preoperative caloric sensitivity and inversely with tumor size. The correlation between the SVH and SVV was high both before and after surgery (r(s) > 0.74; p < 0.001). CONCLUSIONS: The long-term compensation of static tilt perception was dependent on age and not on dynamic canal functions. We propose an idiosyncrasy in the SVH and SVV compensation after unilateral vestibular deafferentation, incongruous with the general course of vestibular compensation. The results suggest a probable dependence on non-vestibular information, i.e. proprioception, in facilitating compensation of static vestibular deficits. The similarity between the SVH and SVV measurements confirms that either test can be used clinically for patients with vestibular lesions.

Adolescent↗
PubMed2003

Zebris versus Myrin: a comparative study between a three-dimensional ultrasound movement analysis and an inclinometer/compass method: intradevice reliability, concurrent validity, intertester comparison, intratester reliability, and intraindividual variability.

STUDY DESIGN: Experimental study. OBJECTIVES: To compare two devices for measuring cervical range of motion, a three-dimensional ultrasound motion device (Zebris) and a gravity-reference goniometer (Myrin). SUMMARY OF BACKGROUND DATA: Assessment of cervical range of motion is used to evaluate the effect of different treatments, determine impairment, and ascertain the relationship between neck disorders and cervical spine mobility. METHODS: Sixty "neck-healthy" volunteers (25 men, 35 women; mean age 38 years, range 22-58 years) performed active maximal movements in flexion-extension, rotation, and lateral flexion. Maximal cervical range of motion was recorded simultaneously with the Zebris and Myrin devices. Intradevice reliability, concurrent validity, intertester comparison, intratester reliability, and intraindividual variability were computed. RESULTS: Our study showed good agreement of full-cycle cervical range of motion measurement between devices, testers, and the test and retest (intraclass correlation [ICC] was >0.90 for intradevice reliability, >0.93 for concurrent validity, and >0.92 for intratester reliability). Method error, assessed with the within-subject coefficient of variation for 95% of the measurements, was 5.4% to 11.1% for intradevice reliability, 4.4% to 7.6% for concurrent validity, 3.6% to 7.6% for intratester reliability, and 5.3% to 9.9% for individual variability. Individual variability did not increase with an increased cervical range of motion. CONCLUSION: Both devices are reliable and showed good agreement. We conclude that the two techniques can be used interchangeably. Our study supports the continued use of the Myrin-a gravity-reference goniometer in routine clinical orthopedic work. The more sophisticated three-dimensional method adds information and allows evaluation of combined motion in two and three dimensions and is suitable for research.

Adult↗
PubMed2003

Phobic postural vertigo: body sway during vibratory proprioceptive stimulation.

Phobic postural vertigo patients might rely more on proprioceptive than visual cues to regulate stance. We tested 14 phobic postural vertigo patients and 24 healthy subjects with posturography during quiet stance and periods of vibratory proprioceptive calf muscle stimulation, both with eyes open and closed. During quiet stance phobic postural vertigo patients showed higher torque variance than healthy subjects, especially above 0.1 Hz. Vibratory proprioceptive stimulation increased the differences between healthy subjects and phobic postural vertigo patients. The patients were less able to use vision to counteract vibration-induced movements. Phobic postural vertigo patients are more sensitive to proprioceptive disturbances than healthy subjects are, and less apt to use visual information to control upright stance. This might be part of an anxious mode of balance control.

Adult↗
PubMed2003

Postural control adaptation during galvanic vestibular and vibratory proprioceptive stimulation.

The objective for this study was to investigate whether the adaptation of postural control was similar during galvanic vestibular stimulation and during vibratory proprioceptive stimulation of the calf muscles. Healthy subjects were tested during erect stance with eyes open or closed. An analysis method designed to consider the adaptive adjustments was used to evaluate the motion dynamics and the evoked changes of posture and stimulation response. Galvanic vestibular stimulation induced primarily lateral body movements and vibratory proprioceptive stimulation induced anteroposterior movements. The lateral body sway generated by the galvanic stimulation was proportionally smaller and contained more high-frequency movements (> 0.1 Hz) than the anteroposterior body sway induced by the vibratory stimulation. The adaptive adjustments of the body sway to the stimulation had similar time course and magnitude during galvanic and vibratory stimulation. The perturbations induced by stimulation were gradually reduced within the same time range (15-20 s) and both kinds of stimulation induced a body leaning whose direction was dependent on stimulus. The similarities in the adjustment patterns suggest that postural control operates in the same way independent of the receptor systems affected by the disturbance and irrespective of whether the motion responses were induced in a lateral or anteroposterior direction.

Adaptation, Physiological↗
PubMed2002

Visual influence on postural control, with and without visual motion feedback.

Body sway was investigated in 20 healthy subjects to determine whether visual input must contain motion feedback information from the surroundings in order to influence postural control. Posturography was used to record body sway under the following visual conditions: eyes open with or without a restricted visual field; eyes open in ganzfield white light; eyes open in darkness with a head-fixed visual target; eyes open in darkness; and eyes closed in darkness. Stance was perturbed by means of a pseudorandomly applied vibratory stimulation to the calf muscles. Least sway was found with eyes open in an unrestricted visual field but increased in a restricted visual field. Greatest sway was found without visual motion feedback, i.e. under the following conditions: eyes closed; eyes open in darkness; eyes open in ganzfield white light; and with a head-mounted fixation point. Sway was significantly (p < 0.05) greater with eyes open in darkness compared with eyes closed during the initial 50 s with perturbations. After 150 s, sway was almost identical under the four test conditions without visual motion feedback. Standing with eyes open in darkness was initially a disadvantage compared with having the eyes closed. The postural control system may be programmed to expect visual feedback information when the eyes are open, which may delay changes in postural strategy.

Adaptation, Physiological↗
PubMed2002

Peripheral vestibular disorders with acute onset of vertigo.

Disorders of the vestibular nerve and end organs are the most common causes of vertigo. The advances in recognizing different forms of canalolithiasis and cupulolithiasis, which sometimes present with continuous positional nystagmus, have revealed a peripheral vestibular aetiology in which central nervous system lesions were previously suspected. Treatments using repositioning manoeuvres are also successful in cases in which nystagmus does not appear, and when administered by less specialized physicians. In acute vestibulopathy, suspicions of the activation of herpes virus infections as a causative agent are increasing, but no reports on the treatment of such infections are yet available. New treatments are in development for use in Ménière's disease.

Acute Disease↗