The Value Of The Vestibular Evoked Myogenic Potential Check For The Clinical Assessment Of Posterior Circulation Transient Ischemic Attacks

Objective:To discuss the changes of VEMP in patients with the posterior circulation transient ischemic attacks, and the clinical significance for the clinical assessment of disease and prognosis; further reveal the pathogenesis of the posterior circulation transient ischemic attacks, through the evaluation of vestibular and brain stem functions of the patients with posterior circulation transient ischemic attacks. Methods:Record the P13-N23wave latency, amplitude changes of the71PCTIA patients and68normal subjects by the use of binaural short acoustic stimulus, and calculate the latency difference between the ears (API3), amplitude ratio between the ears (SR). All subjects were screened whether they have posterior circulation transient ischemic attacks by the TCD. Results:In this study there are71PCTIA patients were detected, and there are41cases (73.47%) of the VEMP abnormalities in the PCTIA group, whereas in the normal control subjects, only6cases (8.82%) of the VEMP abnormalities. There is a statistically significant difference between the two groups (P<0.05).In the PCTIA group the PI3、N23wave latency extended and the amplitude decreased to varying degrees than the normal group.Which the PI3wave latency:the PCTIA group (left18.59ms, right19.57ms) was longer than the normal control group (left14.14ms, right14.11ms);N23wave incubation period:the PCTIA group (left31.81ms, right35.68ms) was longer than the normal control group (left24.52ms, right24.10ms); P13-N23amplitude:the PCTIA group (left78.74μv, right79.95μv) was significantly less than the normal control group (left157.3μv, right151.4μv). There are statistically significant between the two groups (P<0.05); The latency difference between the ears(ΔP13):the PCTIA group (2.33ms) was wider than the normal control group(0.28ms); amplitude ratio between the ears (SR):the PCTIA group (1.22) slightly larger than the normal control group (1.08). There are statistically difference between two groups (P<0.05).In the study, a total of29cases of the posterior circulation TIA patients with the VEMP abnormal after the treatment for14days to be rechecked VEMP,there are21cases VEMP check which was completely back to normal, and eight patients the VEMP check which was also significant recovery.The rise of the VEMP abnormal rates can be caused by the PCTIA patients with age increases (P<0.05). Conclusion:P13-N23wave latency extended and the latency difference between the ears (ΔP13)increased which can be used as the reference index of the VEMP examination to determine whether there is disorders of the brain nerve pathways in the PCTIA patients. The rise of the VEMP abnormal rates can be caused by the PCTIA patients with age increases.The VEMP can be used as a new checking of the evoked potential in patients with PCTIA for aid to determine whether there is impairment of the brain stem function.