Table 4

Summary of sleep patterns

Patient		Total sleep time (% of study duration)		Time to sleep onset (min)		Sleep stages (% of total sleep time)		Arousals (events/hour)
Patient		Total sleep time (% of study duration)		Time to sleep onset (min)		I/II	III/IV	Arousals (events/hour)	REM
Group A
1	56	23	92	0	8	13
2	—	^*12	—	—	—	—
3	71	15	100	0	0	>60
4	79	14	88	0	12	>60
5	82	24	55	22	23	14
6	69	32	43	32	24	21

Group B
10	41	17	43	57	0	0
11	82	15	31	23	47	0
12	40	92	51	37	11	0
13	60	20	78	10	12	>60
14	67	44	48	30	22	0
15	39	36	31	42	27	0

Group A and B=patients with a reduced and normal ventilatory sensitivity to inhaled CO₂ respectively. For patient 2, time to sleep onset (^*) was taken from the first indication of slowing of the EEG frequency; other sleep parameters were not calculated because the EEG was atypical (see text).