OBJECTIVETo discuss the objective characteristics and mechanism of nystagmus direction, intensity and time in horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV) .

METHODSA total of 233 patients with HSC-BPPV, whereas 179 horizontal semicircular canalithasis (HSC-Can) and 54 horizontal semicircular cupulolithiasis (HSC-Cup) were involved respectively. The induced nystagmus in roll tests recorded by video-nystagmograph(VNG) , whose direction, intensity and time characteristics were compared in various BPPV.

RESULTSHorizontal nystagmus was both induced by turning left or right in HSC-BPPV roll tests. The direction of the induced nystagmus was the same with turning in HSC-Can. The latency, duration time and intensity ([AKx(-)D] ± s) turning to lesion and normal side were (1.922 ± 1.501)s and (1.447 ± 0.855)s, (25.620 ± 10.409)s, and (22.110 ± 10.931)s, (56.441 ± 33.168)°/s and (24.239 ± 13.892) °/s in HSC-Can. The latency, duration time and intensity turning to lesion side were larger than normal side (t = 3.715, 15.219 and 4.070, P < 0.01) , the difference was statistically significant, and the intensity rate was about 2: 1. The direction of the induced nystagmus was opposite to turning in HSC-Cup. The intensity turning to normal side was larger than lesion side obviously. The intensity rate was about 2: 1, the difference was statistically significant (t = -7.634, P < 0.01) . While the latency and intensity of turning to lesion side in HSC-Can were larger than turn to normal side in HSC-Cup, and the difference detected no statistically significant difference (t = 1.554 and 0.305, P > 0.05).

CONCLUSIONSThe induced nystagmus intensity of head to two sides in roll tests for HSC-BPPV both follow Ewald's law, and the ratio between stronger and weaker are both 2: 1. These nystagmus parameters of VNG in roll tests are an objective guideline for BPPV diagnosis.

Benign Paroxysmal Positional Vertigo ; complications ; diagnosis ; Electronystagmography ; Head ; Humans ; Nystagmus, Pathologic ; complications ; diagnosis ; Semicircular Canals ; Vertigo

An extraordinary eye movement was seen in a vegetative patient. His eyeballs were exotropic in the primary position and showed dissociated nystagmus which appeared alternately in each eye every few seconds. He also had palatal myoclonus quite asynchronous with the nystagmus. To our knowledge, there has been no such nystagmus documented in the literature. We report the new nystagmus with his EOG and brain MRI.
Electrooculography ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Myoclonus/*complications/diagnosis ; Nystagmus, Pathologic/*complications/diagnosis ; Palatal Muscles

OBJECTIVE: To study the changes of visual nystagmography(VNG) in patients with vertebrobasilar transient ischemic vertigo(VBTIV), explore their clinical value in diagnosis of the patients with VBTIV. METHOD: Thirty-eight patients who complained vertigo and imbalance with VBTIV were selected as experimental group for testing of visual nystagmography (VNG). Twenty normal persons were chosen as control group. The result was analyzed. RESULT: In the experimental group, there was one case that had spontaneous nystagmus and 29 cases (76.3%) with positional nystagmus. The positional nystagmus intension in those patients was (4.08+/-3.18) degrees/s, which was much higher as compared with the control group( P <0.01). The incidence was 39.5% for positioning test. One or more abnormal findings for visual-oculomotor system examination were shown in 28 patients (73.7%). These abnormal findings included saccade test in 26 cases (68.4%), eye tracking test type III in 13 cases and type IV in 3 cases in all 16 cases (42.1%), optokinetic nystagmus in 17 cases (44.7%). There was none with gaze nystagmus. Caloric test showed canal paresis in 19 cases (50.0%) and directional preponderance in 6 cases (15.9%). In Amount distributing of the general slow phase velocity there is a difference between test group and control group. CONCLUSION Not only vestibular centrum but also peripheral system was involved in patients with VBTIV. These results suggest that VNG be used as important diagnostic test for patients with VBTIV and might be helpful for the location diagnosis of VBTIV.
Adult ; Case-Control Studies ; Electronystagmography ; Female ; Humans ; Male ; Middle Aged ; Nystagmus, Optokinetic ; Nystagmus, Pathologic ; complications ; diagnosis ; Vertebrobasilar Insufficiency ; complications ; physiopathology ; Vertigo ; etiology ; physiopathology ; Vestibular Function Tests

To get a better insight into the clinical differentiation between vertigo of cerebrovascular origin and of aural origin, we investigated radiologically proven stroke patients who presented with vertigo as an initial clinical manifestation. Of 154 stroke patients, 30 patients with vertigo (20%) had the relevant lesion, demonstrated with the initial computerized tomographic scan (13 patients) or the follow-up magnetic resonance imaging (MRI) study (17 patients) of the brain. Every lesion was in the vertebrobasilar arterial territory; 19 in the cerebellum, 8 in the pons, and 3 in the medulla oblongata. Although 12 of the 30 patients (40%) presented with vertigo in isolation at the onset of stroke, eight patients (27%) developed additional neurologic abnormalities from four hours to seven days later. Patients with isolated vertigo (13%) had the small lesion exclusively in the cerebellum of the PICA medial branch territory. The most frequent accompanying neurological sign was swaying in the cerebellar and medullary lesion, and dysarthria in the pontine lesion. The direction of nystagmus or swaying did not match the lesion side in some patients. Our findings suggest that cerebellar stroke may commonly manifest isolated vertigo or vertigo with swaying mimicking labyrinthine disorder, particularly at the onset of the disease. MRI study and tests for truncal ataxia and lateropulsion may be crucial for the detection of vertigo of cerebrovascular origin.
Adult ; Cerebrovascular Disorders/complications/*radiography ; Diagnosis, Differential ; Female ; Human ; Male ; Nervous System Diseases/etiology ; Nystagmus, Pathologic/etiology ; Prospective Studies ; Sensation Disorders/*diagnosis ; *Tomography, X-Ray Computed ; Vertigo/complications/*radiography