ABSTRACT
BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the usefulness of computerized dynamic posturography (CDP) in patients with acute vestibular neuritis (AVN) by identifying the recovery period of Sensory Organization Test (SOT) and comparing the result of SOT with those of the vestibulo-ocular reflex (VOR) tests and subjective symptoms. SUBJECTS AND METHOD: A prospective study was conducted on 41 patients who were diagnosed with AVN. The SOT was measured daily until the equilibrium composite score recovered the normal value. A survey, composing of questionnaires on Visual Analogue Scale (VAS), Dizziness Handicap Inventory (DHI), motion sensitive quotient (MSQ) and Activities-Specific Balance Confidence Scale (ABC), was conducted on the patient's initial visit and on the day the normal value of SOT was recovered. Videonystagmography and the caloric test were also performed, and the results were compared with those of the SOT. RESULTS: The mean duration from the onset of vertigo to the recovery of SOT scores was 3.7±2.9 days (median 3.0 days) and that from the onset of vertigo to the disappearance of spontaneous nystagmus was 17.1±27.2 days (median 6.0 days). The scores of 4 questionnaires (VAS, DHI, MSQ, and ABC) were significantly different between the initial day and the day of recovery to the normal value of SOT (p<0.001). However, the velocity of spontaneous nystagmus on the initial visit and the degree of canal paresis from the caloric test showed no significant correlations to recovery duration from the onset of vertigo to the normalization of SOT score. CONCLUSION: The recovery duration of vestibulospinal reflex (VSR) is much shorter than that of VOR in patients with AVN. The recovery of subjective symptoms showed close correlation with the recovery of VSR, but the results of VSR was not correlated with that of VOR. Therefore, CDP could be a very useful test for monitoring the resolution of subjective symptoms in patients with AVN.
Subject(s)
Humans , Caloric Tests , Compensation and Redress , Cytidine Diphosphate , Dizziness , Methods , Paresis , Prospective Studies , Reference Values , Reflex , Reflex, Vestibulo-Ocular , Vertigo , Vestibular NeuronitisABSTRACT
BACKGROUND AND OBJECTIVES: Force sensitive resistors (FSR) were used to measure the body sway to galvanic vestibular stimulation (GVS), and compared with the response obtained from force platform in normal subjects. MATERIALS AND METHODS: Bipolar galvanic stimulation was applied to the bilateral mastoid process with intensity of 0.5-1.5 mA and duration of 1 sec in 3 different head positions of forward, rightward, and leftward. RESULTS: Elevation of anterior pressure curve and depression of posterior pressure curve resulting from forward body sway were recorded in both feet by FSR. Forward body sway induced forward deviation of the center of pressure in force platform. Elevation of pressure curve in left foot and depression of the curve in right foot resulting from leftward body sway were recorded by FSR. Leftward body sway induced left deviation of the center of pressure in force platform. Orientation of the body sway induced by GVS was directed towards the anode side in the head facing forwards. Leftward and backward body sway resulting from cathodal stimulation on left mastoid process in leftward rotation of the head position and leftward and forward body sway resulting from cathodal stimulation on left mastoid process in rightward rotation of the head position were recorded by both FSR and force platform. Reaction time of GVS did not show any significant difference between FSR and force platform. CONCLUSION: These results indicate that FSR could be used to evaluate the vestibulospinal reflex to GVS.
Subject(s)
Depression , Electrodes , Foot , Head , Mastoid , Orientation , Reaction Time , ReflexABSTRACT
To investigate the effects of electrical stimulation on vestibular compensation, which is the recovery of vestibular symptoms following unilateral labyrinthectomy (UL), intermittent electrical stimulation was applied to the injured vestibular portion in Sprague-Dawley rats. Vestibuloocular and vestibulospinal reflexes, electrical activity and expression of c-Fos protein in medial vestibular nuclei (MVN) were measured with time following UL. Spontaneous nystagmus occurred with frequency of 2.9+/-0.2 beats/sec at 2 hours after UL and disappeared after 72 hours. Electrical stimulation decreased the frequency of nystagmus significantly till 24 hours after UL. Roll head deviation was 107+/-9.7degree at 2 hours after UL and the deviation was maintained till 72 hours, but electrical stimulation decreased the deviation significantly 6 hours after UL. Resting activity of type I neurons in ipsilateral MVN to the injured vestibular side decreased significantly compared with control at 6 and 24 hours after UL, but the activity of type I neurons was recovered to control level by electrical stimulation at 24 hours after UL. Gain of type I neurons induced by sinusoidal rotation of 0.1 Hz decreased significantly till 24 hours after UL, but electrical stimulation restored the activity at 24 hours. The gain of type II neurons decreased significantly at 6 hours after UL, but electrical stimulation restored the activity. Expression of c-Fos protein was asymmetric between bilateral MVN till 24 hours after UL, but the asymmetry disappeared by electrical stimulation 6 hours after UL. These results suggest that electrical stimulation to the injured vestibular portion facilitates vestibular compensation following UL by restoration of symmetry of neuronal activity between bilateral vestibular nuclei resulting from increased activity in ipsilateral vestibular nuclei to the injured side.