Table 1.

Clinical features of subjects with motion-triggered (MT) and non-motion-triggered (non-MT) chronic rocking dizziness.

	Motion triggered	Non-motion triggered
Number of subjects	76	41	p value
Percent female	62 (82%)	34 (83%)	1.00
Age of onset of rocking dizziness
Median	45 yrs	40 yrs	0.30
Range	12–69 yrs	16–71 yrs
Motion trigger
Sea travel	50 (66%)
Air travel	27 (36%)
Land travel	7 (9%)
Number of distinct episodes ≥ one month
One	46 (61%)	24 (59%)	0.19
Two	11 (14%)	1 (2%)
Three	7 (9%)	0 (0%)
Four	3 (4%)	1 (2%)
Five	4 (5%)	1 (2%)
>Five	1 (1%)	6 (15%)
Unknown/unsure	4 (5%)	8 (20%)
Duration of first episode
Mean ± s.d.	37.0 ± 47.6 mo	79.9 ± 69.6 mo	<0.001
Median	18.0 mo	58.0 mo	<0.001
Range	1–204 mo	19–255 mo
Symptoms at time of study
Continuing	57 (75%)	35 (85%)	0.25
Resolved	19 (25%)	4 (10%)
Unknown	0 (0%)	2 (5%)
Effect of re-exposure to passive motion	n = 75	n = 40
Decrease rocking	65 (87%)	28 (70%)	0.042
No change	9 (12%)	8 (20%)
Increase rocking	1 (1%)	4 (10%)

s.d.: standard deviation; yrs: years; mo: months.