ABSTRACT
A review of more than 20 years of experience with vibratory stimulation in vestibular diseases is given. Vibrations in a frequency frame of 30-60 Hz are applied on the mastoid during 20 s. Eye movements are recorded by video-oculography to detect a vibration-induced nystagmus (VIN). A VIN occurs in cases of a side difference between the peripheral vestibular receptors beating to the side of better excitability. In patients with central lesions, a VIN does not appear generally, only exceptionally if the lesion is located laterally in the brain stem. In healthy subjects, a VIN does not occur. The VIN can be considered as an additional tool to detect a peripheral side difference and can reduce the need for caloric stimulation.
Subject(s)
Nystagmus, Pathologic/diagnosis , Vestibular Diseases/diagnosis , Vibration/adverse effects , Adult , Biomarkers/analysis , Female , Humans , Male , Middle Aged , Nystagmus, Pathologic/etiology , Risk Assessment , Sensitivity and Specificity , Vestibular Diseases/etiology , Vestibular Function TestsABSTRACT
The aim of this study was to investigate the relation between the vestibular system and orientation in space and the role of acute vestibular lesions in spatial memory. In a first step it could be shown that determining the visual straight ahead is systematically influenced by caloric irrigation: deviations up to 10 degrees appeared, which are directed to the slow phase of the simultaneously provoked nystagmus. In a second step, 20 healthy subjects and 20 patients suffering from an acute vestibular disorder were asked to adjust a luminous point visual straight ahead. Whereas the healthy subjects' visual straight ahead was in a range of +/-2 degrees, the vestibular patients showed significantly greater deviations. If healthy subjects and patients were asked to replace a luminous point, which was exposed for a short time, to its original position, young and older healthy subjects showed good performance, with an error not greater than 3 degrees, whereas the vestibular patients showed significantly greater inaccuracy. We conclude that the visual straight ahead is a vestibular-dependent parameter of visual orientation and that spatial memory is influenced by acute vestibular lesions. For the first time it is shown that acute vestibular lesions impair spatial memory. This can be explained by the close relationship between the vestibular system and the hippocampus.
Subject(s)
Spatial Behavior , Vestibular Diseases/physiopathology , Vision, Ocular , Adult , Aged , Humans , Middle AgedABSTRACT
In a prospective study, 165 total stapedectomies and 152 small fenestra stapedotomies were performed by three experienced surgeons between 2001 and 2003. In total stapedectomy, a self-made Schuknecht steel wire connective tissue prosthesis, and in stapedotomy, a 0.6-mm platinum wire Teflon piston was used. The pre- and postoperative bone conduction thresholds were compared at the frequencies 250 Hz, 500 Hz, 1 kHz, 1.5 kHz, 2 kHz, 3 kHz and 4 kHz. The postoperative bone conduction between 250 Hz and 3 kHz was significantly better in the total stapedectomy group than in the stapedotomy group. At 4 kHz, both groups showed a slight decrease in bone conduction but the difference was not statistically significant. Therefore, especially in cases with preoperative moderate sensorineural hearing loss, we recommend total stapedectomy using a Schuknecht steel wire connective tissue prosthesis, which offers a stapes-perilymph interface similar to the normal stapes.
Subject(s)
Bone Conduction/physiology , Fenestration, Labyrinth , Ossicular Prosthesis , Otosclerosis/surgery , Perilymph/physiology , Postoperative Complications/physiopathology , Stapes Surgery , Audiometry, Pure-Tone , Auditory Threshold/physiology , Hearing Loss, Conductive/physiopathology , Hearing Loss, Conductive/surgery , Hearing Loss, Sensorineural/physiopathology , Hearing Loss, Sensorineural/surgery , Humans , Otosclerosis/physiopathology , Postoperative Complications/diagnosis , Prospective Studies , Prosthesis DesignABSTRACT
Many arguments give evidence that benign paroxysmal positioning vertigo, one of the most frequent kinds of vertigo, can be reduced to mechanical processes in the vestibular part of the labyrinth. Based on the assumption that otoliths have departed from their normally fixed position in the otolithic membrane and travel in the semicircular canals, clinical observations find their explanation. Latency between the onset of a head movement and the beginning of the vertiginous sensation, its duration and the nystagmic pattern provoked by specific head movements are in good correlation with the canalith hypothesis. Further arguments are the successful treatment by liberatory maneuvers, the relatively high number of recurrences and the change of the affected canal.
