Biofeedback in patients with balance disorders

This dissertation is providing evidence that rehabilitation with biofeedback improves postural stability in patients with poor balance. We used two methods of biofeedback during the rehabilitation of the patient groups, visual control and electrotactile stimulation of the tongue. The thesis is based on the body of five scientific publications. The introduction is explaining how postural stability is controlled and how this is assessed by posturografic examination. Discussed also is neurorehabilitation using biofeedback, in patients with poor balance. Throughout the first experiment, we studied the effect of rehabilitation using visual feedback in patients during the early postoperative period after resection of vestibular schwannoma. The results showed stability adaptation is accelerated, using visual biofeedback in patients who have early postoperative rehabilitation, when compared to patients who did not use biofeedback during the postoperative rehabilitation. In the second experiment, we focused on assessing the subjective visual vertical in patients with defined postural deformity - idiopathic scoliosis. Our results showed that patients with idiopathic scoliosis (IS) have an abnormal perception of subjective visual vertical when compared to age matched healthy individuals. This finding supports the..

Trajectory length of pitch vs. roll: Technique for assessment of postural stability

Background: Patients with disorders of nervous or musculoskeletal system often show instability of the body segments during the stance tasks. Traditionally, stabilometric platforms are used to measure body sway. However, these devices are expensive and do not allow the evaluation of the individual movements of body segments. At present, accelerometers or gyroscopes are used to measure the movements of the body segments. For these new motion capture (MoCap) systems, methods for quantitative evaluation of a body segment movement are being developed. Objective: The main objective of this paper is to describe a new method which would be suitable for quantifying postural stability and identifying differences in balance control using data recorded by an inexpensive 2-DoF gyroscope. Methods: Method based on total length of trajectory (TL) in a 2-D plot of angles was proposed for quantitative evaluation of the trunk and feet sway. The sway was measured during quiet stance of ten middle-aged patients (Pts) with degenerative cerebellar disorder and eleven young healthy subjects (HS) standing with eyes open (EO) on a firm surface (FiS) and eyes closed (EC) on a foam surface (FoS). Data were obtained using three gyroscopes (Xsens) to measure roll and pitch angular movements of the trunk, and left and right foot. The pitch versus roll plots of the trunk and feet were created and the trajectory lengths of the pitch vs. roll angle were calculated. Results: Although the results vary while measuring different segments of the body, the method showed significant differences between the two different groups. Significant differences between the HS and Pts were found in EO standing on a FiS for TLs of the trunk (p = .02) and TLs of the feet (p < .01). Similarly in EC standing on a FoS significant differences (p < .01) between groups were found for TLs of both the trunk and the feet (p < .01). Conclusions: It was found that the TL of pitch vs. roll is suitable for quantifying postural sway and identifying differences in balance control. The technique, based on the length of the pitch angle vs. roll angle trajectory can be used even where MoCap systems can only measure two sway angles which could extend the clinical information of the body sway

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation (p<0.05). This trial is registered with clinical study registration number NCT02963896