Analysis of brain-stem auditory evoked potential and visual evoked potential in patients with Parkinson disease

摘要

BACKGROUND: With the development of neuroelectrophysiology, it had been identified that all kinds of evoked potentials might reflect the functional status of corresponding pathway. Evoked potentials recruited in the re search of PD, it can be known whether other functional pathway of nervous system is impaired. OBJECTIVE: To observe whether brainstem auditory and visual passageway are impaired in patients with Parkinson disease (PD), and compare with non-PD patients concurrently. DESIGN: A non-randomized concurrent controlled observation. SETTINGS: Henan Provincial Tumor Hospital; Anyang District Hospital. PARTICIPANTS: Thirty-two cases of PD outpatients and inpatients, who registered in the Department of Neurology, Anyang District Hospital from October 1997 to February 2006, were enrolled as the PD group, including 20 males and 12 females, aged 50-72 years old. Inclusive criteria: In accordance with the diagnostic criteria of PD recommended by the dyskinesia and PD group of neurology branch of Chinese Medical Association. Patients with diseases that could cause Parkinson syndrome were excluded by CT scanning or MRI examination. Meanwhile, 30 cases with non-neurological disease were selected from the Department of Internal Medicine of our hospital as the control group, including 19 males and 11 females, aged 45-70 years old. Including criteria: Without history of neurological disease or psychiatric disease; showing normal image on CT. And PD, Parkinson syndrome and Parkinsonism-plus were excluded by professional neurologist. All the patients were informed and agreed with the examination and clinical observation. METHODS: The electrophysiological examination and clinical observation of the PD patients and controls were conducted. The Reporter type 4-channel evoked potential machine (Italy) was used to check brain-stem auditory evoked potential (BAEP) and visual evoked potential (VEP). Why to be examined was explained to test taker. BAEP recording electrode was plac.ed at Cz, while the reference one placed at ipsilateral ear lobe, according to international standard 10-20 system. The short sound was used to stimulate the target ear with the interval of 0.1 ms, the frequency of which was 9.9 Hz, intensity was 110 db, superposition was 2 048 times while the opposite one screened noisily, then repeated for twice or more in the same way. The latencies of waves Ⅰ - Ⅴ, and the intervals of waves Ⅰ - Ⅴ, Ⅰ - Ⅲ, Ⅲ- Ⅴ were measured. The purpose of the detection should be explained to the patients in advance. VEP recording electrode was placed at the point 5 cm above occipital tuberosity and 5 cm beside the line connecting the previous point and the preauricula point on either side, while the reference electrode placed at Fz. The whole visual chessboard-grid stimulation was used, superposition of which was 250 times, then repeated for twice or more in the same way. The results of BAEP and VEP detections were observed in the two groups.The differences of the measurement data were compared with the t test.MAIN OUTCOME MEASURES: ① Indexes of BAEP analysis: peak latencies (PL) of waves Ⅰ, Ⅲ and Ⅴ, and the inter-peak latencies (IPL) of waves Ⅰ - Ⅴ, Ⅰ - Ⅲ, Ⅲ- Ⅴ. ② The indexes of VEP analysis: P100 PL and the abnormal rate of P100 amplitude.RESULTS: All the 32 PD patients and 30 patients with non-neurological diseases were involved in the analysis of results. ① BAEP: The wave Ⅲ PL and wave Ⅴ PL of the PD patients were obviously different from those in the control group [(3.87±0.30), (5.79±0.3) ms; (3.56±0.22), (5.48±0.26) ms, t=5.83, 5.85, P ＜ 0.01]. The abnormal rate of the PD patients was 50%, including that of wave Ⅲ PL and wave Ⅴ PL was 22% and 19% respectively. ② VEP: The P100 PL of the PD patients was obviously different from that in the control group [(105.17±12.42), (98.62±9.46) ms, t =2.49, P＜ 0.05]. The P100 PL was abnormal in 10 cases (31%), and P100 wave amplitude was abnormal in 14 cases (44%). CONCLUSION: ① VEP and BAEP abnormalities do occur and brainstem auditory and visual pathway are impaired. ② Besides extracorticospinal tract, the sensory system is also involved in PD patients. ③ BAEP and VEP can be taken as the objective indicators for the clinical evaluation of PD.