Objective To observe auditory brainstem response evoked at different electrode positions adopting electrode slices .Methods The ABRs of 12 normal guinea pigs (24 ears)were recorded by two methods using clicks as stimulation .Active electrode was positioned at the vertex while the ground electrode at the nose .The reference e‐lectrode was placed on bilateral pinnas or mastoids .Then observe waveforms ,response thresholds (RT) ,peak la‐tencies(PL) and inter-peak latencies (IPL)of ABR .Results No significant difference were observed in the RT ,Ⅰ ,Ⅱand Ⅲ PL ,Ⅰ - Ⅲ IPL of ABR between the two methods(P>0 .05) .When stimulation was decreasing and with the reference electrode slices placed at bilateral pinnas ,waveⅡpeak was stable and discernable of ABR record‐ings across twenty -four ears of guinea pigs .The amplitude decreased more slowly than any other waves ,and dis‐appeared at the last .While reference electrode slices were placed on bilateral mastoids ,the amplitude of wave Ⅲ de‐creased more slowly than any other waves except wave Ⅳ ,and disappeared at lost .Ⅱ - Ⅲ ,Ⅲ - Ⅳ IPL became shorter .These two positions both recorded amplitude higher and PL advanced for wave Ⅳ as the stimulation de‐creased by 20 to 40 dB nHL ,and Ⅲ - Ⅳ IPL became shorter .This phenomenon was more obvious when reference electrode was placed at mastoid .Conclusion Wave Ⅱwas more stable and discernible with reference electrode placed at the bilateral pinnas .Therefore wave Ⅱ recorded by this way can be a new method to record the ABR threshold of g uinea pig s .

Background: and Purpose Intracranial vertebrobasilar atherosclerotic stenosis (IVBAS) is a major cause of posterior circulation stroke. Some patients suffer from stroke recurrence despite receiving medical treatment. This study aimed to determine the prognostic value of a new score for the posterior communicating artery and the P1 segment of the posterior cerebral artery (PCoA-P1) for predicting stroke recurrence in IVBAS. Methods: We retrospectively enrolled patients with severe IVBAS (70%–99%). According to the number of stroke recurrences, patients were divided into no-recurrence, single-recurrence, and multiple-recurrences groups. We developed a new 5-point grading scale, with the PCoA-P1 score ranging from 0 to 4 based on magnetic resonance angiography, in which primary collaterals were dichotomized into good (2–4 points) and poor (0 or 1 point). Stroke recurrences after the index stroke were recorded. Patients who did not experience stroke recurrence were compared with those who experienced single or multiple stroke recurrences. Results: From January 2012 to December 2019, 176 patients were enrolled, of which 116 (65.9%) had no stroke recurrence, 35 (19.9%) had a single stroke recurrence, and 25 (14.2%) had multiple stroke recurrences. Patients with single stroke recurrence (odds ratio [OR]= 4.134, 95% confidence interval [CI]=1.822–9.380, p=0.001) and multiple stroke recurrences (OR=6.894, 95% CI=2.489–19.092, p<0.001) were more likely to have poor primary collaterals than those with no stroke recurrence. Conclusions The new PCoA-P1 score appears to provide improve predictions of stroke recurrence in patients with IVBAS.