Objectives The nystagmus evoked by an angular velocity step is influenced by the cupula dynamics and the status of velocity storage mechanisms. This study questioned whether the cupulolithiasis of horizontal canal benign paroxysmal positional vertigo (HC-BPPV) affects the time constant or gain of the velocity step test.
Methods We performed a retrospective study of 30 patients who diagnosed with HC-BPPV and performed rotary chair test at Dankook University Hospital from June 2010 to May 2017. All patients had normal vestibular function on the sinusoidal harmonic acceleration test. According to the direction of nystagmus on the head roll test, we further divided the patients into “geotrophic” (canalolithiasis) and “apogeotrophic” (cupulolithiasis) groups. We compared the time constant (Tc), gain, and directional preponderance (DP) between the 2 groups. We also compared the time constant and gain between lesion side of BPPV and normal side in each group.
Results In the supine head roll, geotrophic nystagmus observed in 14 patients and apogeotrophic nystagmus observed in 16 patients. When parameters of the velocity step test compared according to lesion side of BPPV (per-rotary of lesion side, postrotary of lesion side, per-rotary of normal side, and postrotary of normal side), there were no significant differences in Tc, gain, and DP between the 2 groups. There were also no significant differences in Tc and gain between lesion side and normal side in each group.
Conclusions We assumed that cupulolithiasis of HC-BPPV could affect the cupular deflection evoked by an angular velocity step, but there were no significant differences in Tc and gain between patients with cupulolithiasis and canalolithiasis.
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Influence of Otoliths on the Vestibulo-Ocular Reflex in Horizontal Canal Benign Paroxysmal Positional Vertigo Hee Soo Yoon, Jae Yeong Jeong, Jae Ho Chung, Ha Young Byun, Chul Won Park, Seung Hwan Lee Research in Vestibular Science.2020; 19(2): 49. CrossRef
OBJECTIVE: Vestibular neuritis (VN) is one of the most common causes of acute spontaneous vertigo. However, such dizziness symptoms in patients with VN vary among patients, and various methods are used to evaluate subjective vestibular symptoms following attack of VN. Studies on correlation between subjective vestibular symptom changes and result of rotation chair test after vestibular rehabilitation therapy (VRT) have not been reported.
Therefore, we compared change of dizziness handicap inventory (DHI) and results of rotation chair test in patients with VN between attack and 3 month later following VRT.
METHODS Forty-seven patients were included in this study.
In patients with VN, DHI and rotation chair test were performed at the time of VN attack and recovery time of 3 months after VN attack.
RESULTS In general, the DHI score and the percentage of directional preponderance (DP) in a rotation chair test performed on patients with VN have all decreased. However, the changes in these results were not statistically significant. DP% difference and DHI score were compared to each other among patients with VN and showed no relational significance to each other (r=0.326).
CONCLUSION The degree of improvement in a rotation chair test done on patients with VN did not reflect the severity of improvement for symptom like dizziness.