Objective To study the effect of passive movement test on neurobehavioral score of neonatal rabbit and establish an improved neurobehavioral scoring protocol.Methods Twelve pregnant New Zealand white rabbits were randomly divided into three groups (n =4 in each).In 25 and 28 min ischemic group,uterine blood supply was blocked for 25 min and 28 min respectively,but not in the control group.The general information of neonatal rabbit was recorded.All live birth neonatal rabbits in each group were again randomly divided into forward assessment group,backward assessment group and simplified assessment group.Forward assessment group and backward assessment group were assessed with the published protocol in forward and reverse order respectively,and the simplified assessment group was assessed with improved protocol in forward order.The results of assessment was recorded and the effect of different assessment methods on neurobehavioral score was evaluated.Meanwhile,the pathohistological changes in the brains of neonatal rabbits were observed,and the correlation between the neurobehavioral test score and the duration of intrauterine ischemic and the amount of apoptosis neural cell was analyzed.Spearman rank correlation test,single factor analysis of variance,Kruskal Wallis H test,Wilcoxon signed rank test and Chi-square test were used for statistical analysis.Results The stillbirth rate in control group,25 and 28 min ischemic group was 0.0％(0/28),16.7％(6/31) and 37.9％(11/29) with statistical significance (x2 21.33,P＜0.05).The amount of apoptosis brain cells in the three groups was 0 (0 1),7 (6-10) and 25 (22-28) respectively (x2 54.39,P＜0.05).The neurobehavioral test score in control,25 min and 28 min ischemic group decreased accordingly [Posture:3.00(2.25 3.00),2.00(1.00 2.00) and 1.00(1.00-1.00) (H=38.47,P=0.00); Righting turns (times):9.00(8.00 9.75),4.00(3.00 5.00) and 1.00(0.00 1.00) (H=52.30,P=0.00); Righting score:2.90(2.80-2.98),2.10 (1.90 2.20) and 1.30(1.001.40) (H 53.53,P 0.00); Locomotion:3.00(2.00 3.00),1.50(1.002.00) and 0.00(0.00-1.00) (H=38.97,P=0.00); Sucking and swallowing:3.00(2.00 3.00),1.50(1.00-2.00) and 1.00(0.00 1.00) (H=42.87,P=0.00); Olfactary stimulation:3.00(3.00-3.00),2.00(2.00 2.00) and 1.00(1.00-2.00) (H=38.43,P=0.00)].There were some differences of neurobehavioral test score between backward and forward assessment within individual group.The posture score and the righting times in backward assessment group were generally lower than those in forward assessment group,and significant difference was shown between the control group and 25 min ischemicgroup [Posture:3.00(3.00 3.00) vs 2.00(2.00 3.00),T=69.0,P＜0.05; 2.00(1.25 2.00) vs 1.00(1.001.75),T=52.0,P＜0.05.Righting turns (times):4.50(4.00-5.75) vs 3.00(2.25 4.00),T=47.0,P＜0.05].The score of olfactory stimulation,sucking and swallowing in backward assessment group were a little higher than that in forward assessment group,but the difference was not predominate (P＞0.05).The neurobehavioral test score in simplified assessment group was consistent with the forward assessment group (P＞0.05).Negative correlation was revealed between the neurobehavioral test score,the duration of intrauterine ischemic and the amount of apoptosis brain cells (all r＜0,P＜0.05),and the correlation in simplified assessment group and forward assessment group were close and obvious ｜ r ｜ ≈ 0.8.Conclusions The classical passive movement test may underestimate neurobehavioral manifestation,while the modified neurobehavioral scoring protocol could accurately evaluate the neurobehavioral damage level of neonatal rabbits with hypoxia ischemic brain damage.