Applied Study Of Brainstem Auditory Evoked Potential And Brain Electrical Activity Mapping In Patients With Vertebrobasilar Systemic Transient Ischemic Attack

Objective: To explore the early diagnostic value ofbrainstem auditory evoked potential(BAEP) and brainelectrical activity mapping(BEAM) in patients withvertebrobasilar systemic transient ischemicattack(TIA). To identify the damaged position andjudge the severity of patient's condition. We triedto investigate the curative effect and to instructclinical treatment and select the best therapy.Methods: We selected 60 inpatients(patientsgroup)with vertebrobasilar systemic TIA diagnosed byclinical standards referred to the fourth nationalcerebrovascular diseases meeting in 1995 in ourhospital, including male 32 cases, female 28 cases,ages were from 35 to 65 years old, average was 47.18±8.14 years old. 50 cases had the same similarsymptoms in the past. The course of disease was fromone month to 16 years old. 35 health controls whoseages and gender were similar to the patients group,including male 19 cases, female 16 cases, ages were5from 30 to 65 years old, average was 46.46±9.70 yearsold. BAEP were performed on both groups in quiet statein 25℃ room with sound insulation. Subjects sat insoft chair, loosen, closed eyes. Cz was referencepoint, A1A2 was record point respectively. Fz wasground electrode. The resistance of electrodes on skinwas less than 5 kΩ. Auditory stimulation wasalternative click sound. Subjective threshold wasexamined first. Those went beyond 60dB were excludedfrom this study. Two ears was given 60dB click oversubjective threshold respectively. We overlapped 1500repeatedly. Two times every side at least. The twobetter overlapping waves were selected and werefiltered, then we marked every wave and measured peaklatency(PL) and interpeak latency(IPL) of Ⅰ Ⅲ Ⅴwith cursor. The data of two group were compared byt test. BEAM was performed in vertebrobasilar systemicTIA patients. BEAM examination used electrode cap withthe machine. It had 21 electrodes laying according tointernational 10/20 systerm. We traced EEG 3 minuteswith the earlobes as reference electrodes, and 30seconds EEG without confusion was input computer toFTT exchange to obtain power ofαβθδ distributionimages.The results were compared with BAEP, and wecombined the patient's manifestation to analyzed therelationship between the condition and the abnormal6degree of BEAM and BAEP. BEAM and BAEP were performedinstantly after admission. The patients with abnormalresults were checked again after a week's treatment.We compared the results among control group,pre-treatment and post-treatment vertebrobasilarsystemic TIA group. Measurement data were expressedwith x ±s and dealt with t test. The size of test tooka=0.05.Results: (1) 45 cases were abnormal in 60vertebrobasilar systemic TIA patients. The abnormalrate of BAEP was 75﹪, including 62.2% brainstemtype(28 cases), 15.6% (7 cases) internal ear type and22.2%(10 cases) mixed type. (2) Ⅰ Ⅴ PL,Ⅲ-ⅤIPL andⅢ-Ⅴ/Ⅰ-Ⅲ were increased very significantly invertebrobasilar systemic TIA group as compared withcontrol group(P<0.01). Ⅲ PL,Ⅰ-Ⅴ IPL wereincreased significantly(P<0.05).Ⅰ-ⅢIPL was nosignificance statisticly(P>.05). (3) In the BAEPindexes, the abnormal rate of Ⅲ-Ⅴ/Ⅰ-Ⅲ>1 wasthe highest(48.3%), then was the prolongation of Ⅲ-Ⅴand Ⅰ-Ⅴ IPL. The abnormal rate was 35%,30%respectively. The bad form of Ⅰ Ⅲ Ⅴ wave was morethan PL prolongation and Amp drop. (4) The abnormalrate of BEAM was 80% in vertebrobasilar systemic TIAgroup. BEAM showed power decreased in occipital or/andtemporal area of the α distribution images or/and7power increased in the same area of the θδdistribution images. (5) The abnormal rate in bothBAEP and BEAM was 63.3% (38 cases) in a same patient.Abnormal BEAM accounted for 16.7% (10 cases). Onlyabnormal BAEP accounted for 11.7%(7 cases). NormalBAEP and BEAM accounted for 8.3%(5 cases). (6) Theabnormal rate after seven days therapy in patientswith vertebrobasilar systemic TIA...