The analysis of smooth pursuit test in unilateral vestibular peripheral vertigo

OBJECTIVE To analyze the result of smooth pursuit test (SPT) in unilateral vestibular peripheral vertigo and investigate its influencing factors. METHOD Smooth pursuit test (SPT) and spontaneous nystagmus (SN) were examined in one hundred and eighty-five patients with unilateral peripheral vertigo (case group) and 51 normal persons (control group) by Video-Nystagmography (Synapsis, France), and the gain of SPT and SN were selected as the observation parameters in order to analyze the waveform and gain of SPT and the relativity between SN and the gain of SPT. RESULT Of the 185 patients, 105 (56.8%), 72 (38.9%) and 8 (4.3%) cases produced I , II and III waveforms respectively. Of these patients, 58 (31.4%) demonstrated SN and none had IV waveform. While of 51 normal persons, 38 (74.5%), 13 (25.5%) persons produced I and II waveforms respectively and there were no III, IV waveforms or SN. There was statistical significance between the strong and weak gain of SPT in these two groups. Weak gain was significantly different between two groups. The strong and weak gain of SPT in case group were 0.86 +/- 0.06, 0.80 +/- 0.06; 0.78 +/- 0.09, 0.65 +/- 0.1; 0.68 +/- 0.13, 0.45 +/- 0.12. The relativity between SN and the gain of SPT was positive when they had same direction (r(s) = -0.63, P<0.05) and negative when opposite (r(s) = 0.34, P<0.05). CONCLUSION I , II, III three waveforms of SPT could appear in unilateral vestibular peripheral vertigo and the corresponding gains are gradually decreasing. SN is the influencing factor of SPT.