Table 2

Paired comparisons between each of the ex-sniffer, chronic sniffer, and encephalopathic sniffer groups and the non-sniffer group for neurological and saccade data

Non-sniffer (n = 34)Ex-sniffer (n = 24)Chronic sniffer (n = 22)Encephalopathic sniffer (n = 16)F statistic
Values are median (range) or mean (SD).
†Scored as the number of participants from each group who show these saccade characteristics.
‡To give meaningful examples of the data, measures of peak velocity and saccade duration were derived from the coefficient and gradient scores, respectively, for saccade amplitudes of 10° and 20°.
*p<0.05; **p<0.01; ***p<0.001; comparisons made between the non-sniffer group and all other groups.
Neurological abnormality score (max = 8)0.5 (1.1)1.3 (1.5)*3.1 (1.8)***5.9 (2.5)***42.4
Visually guided saccades
Saccadic intrusions†104912**
Post-saccadic drift†44212***
Gaze evoked nystagmus†0103*
Hypometric (%)19.4 (5 to 53)22.3 (4 to 59)23.2 (2 to 67)29.5 (4 to 70)*1.5
Hypermetric (%)7.7 (0 to 28)7.0 (0 to 35)6.3 (0 to 18)14.0 (0 to 47)*2.8
Anticipations (%)10.0 (0 to 47)8.5 (0 to 51)13.2 (0 to 42)18.6 (3 to 74)*2.4
Latency (ms)170.2 (22.7)175.5 (25.2)185.2 (27.2)*205.1 (32.1)***7.0
Accuracy (%)98.8 (12.6)95.2 (6.6)94.3 (7.0)93.8 (11.8)1.3
Peak velocity‡
    Coefficient133.7 (20.5)131.7 (19.1)129.3 (23.6)119.4 (23.6)*1.7
    For 10° saccades (°/s)423416409378
    For 20° saccades (°/s)598589578534
Duration‡
    Amplitude gradient2.2 (0.5)2.2 (0.7)2.3 (0.8)2.4 (0.6)1.0
    For 10° saccades (ms)39394041
    For 20° saccades (ms)61616365
Antisaccades
Latency (ms)261.4 (38.4)280.3 (65.0)300.8 (62.8)**406.1 (99.2)***15.4
Error rate (%)16.3 (12.0)26.0 (27.4)40.7 (33.6)***52.3 (37.4)***7.1