The first night effect in multiple sclerosis patients undergoing home-based polysomnography

Figures & data

Table 1 Baseline characteristics

			Insomnia (n=17)	No sleep disorder (n=17)	SRBD (n=7)	PLMD/RLS (n=22)	Total (N=63)
Sex	Female, N (%)		13 (76.5)	14 (82.4)	5 (71.4)	11 (50.0)	43 (68.3)
Age (years)	Mean (SD)		46 (10)	36 (9)	51 (10)	44 (9)	43 (10)
Time since onset (years)	Median (IQR)		9 (7–22)	5 (4–11)	10 (3–24)	11 (4–18)	9 (4–18)
Expanded Disability Status Scale	Median (IQR)		2 (2–3)	2 (2)	4 (3–6)	2 (2–4)	2 (2–4)
Beck Depression Inventory	Median (IQR)		15 (12–23)	5 (2–8)	14 (11–33)	9 (6–16)	10 (6–18)
Modified Fatigue Impact Scale	Median (IQR)		48 (44–54)	20 (2–31)	57 (45–64)	33 (19–48)	38 (20–52)
Fatigue Severity Scale	Median (IQR)		5.7 (5.1–6.5)	3.1 (1.4–4.4)	6.3 (5.7–6.9)	4.0 (2.9–5.4)	4.7 (3.1–6.3)
Disease-modifying therapy	Missings	n	1	1	0	4	6
	Copaxone	n (%)	3 (18.8)	9 (56.3)	3 (42.9)	5 (27.8)	20 (35.1)
	Cortisone plus	n (%)	0	1 (6.3)	0	0	1 (1.8)
	Interferon	n (%)	7 (43.8)	5 (31.3)	3 (42.9)	7 (38.9)	22 (38.6)
	IVIG	n (%)	0	1 (6.3)	0	1 (5.6)	2 (3.5)
	No therapy	n (%)	3 (18.8)	0	1 (14.3)	5 (27.8)	9 (15.8)
	Mitoxantrone	n (%)	2 (12.5)	0	0	0	2 (3.5)
	Natalizumab	n (%)	1 (6.3)	0	0	0	1
Antidepressants	Yes	n (%)	5 (29.4)	5 (29.4)	0	4 (18.2)	14 (22.2)
Psychopharmaka	Yes	n (%)	5 (29.4)	1 (5.9)	2 (28.6)	8 (36.4)	16 (25.4)

Abbreviations:IVIG, polyvalent intravenous globulin; PLMD, periodic limb movement disorder; RLS, restless legs syndrome; SRBD, sleep-related breathing disorder.

Table 2 Hypnogram parameters: night 1 and median change to night 2 (∆: night 2–night 1)

	Insomnia (n=17)	No sleep disorder (n=17)	SRBD (n=7)	PLMD/RLS (n=22)
AI per hour sleep (first night) ∆ second night vs first night	21.0 (14.7–29.3) –1 (–6 to 3) P=0.737	18.9 (13.1–27.0) –1 (–3 to 2) P=0.959	23.6 (11.0–40.6) –3 (–3 to 6) P=0.735	15.9 (12.3–46.0) 0 (–3 to 1) P=0.052
WASO in minutes (first night) ∆ second night vs first night	83 (57–136) –7 (–21 to 36) P=0.962	68 (53–85) –12 (–30 to 0) P=0.112	174 (74–218) –30 (–85 to 3) P=0.176	80 (55–109) –11 (–31 to 0) P=0.029
Number of sleep stage changes (first night) ∆ second night vs first night	157 (116–188) –21 (–26 to 26) P=0.636	163 (138–206) –7 (–51 to 2) P=0.115	153 (109–218) 10 (–24 to 22) P=0.799	146 (123–178) 2 (–36 to 24) P=0.970
Numbers of AWAs (first night) ∆ second night vs first night	25 (22–35) 0 (–5–7) P=0.532	27(17–39) –5 (–9 to 2) P=0.041	34 (27–48) 2 (0 to 7) P=0.498	27 (17–32) 0 (–9 to 5) P=0.808
SE in percent of TSiB (first night) ∆ second night vs first night	72.7 (65.2–81.4) –2.5 (–10.2 to 6.2) P=0.407	82.9 (78.2–86.9) 1.8 (–1.8 to 4.2) P=0.313	66.4 (59.4–84.4) 4.2 (–7.8 to 19.0) P=0.310	76.5 (69.9–83.4) –0.1 (–3.5 to 5.8) P=0.986
N1 and N2 in percent of TB (first night) ∆ second night vs first night	50.8 (43.8–60.9) –3.6 (–12.8 to 3.6) P=0.256	52.3 (46.7–62.1) 0 (–7.0 to 7.8) P=0.959	47.4 (36.2–51.7) 11.0 (–6.2 to 12.4) P=0.398	52.5 (47.1–64.1) 0 (–6.5 to 5.1) P=0.502
REM sleep in percent of TB (first night) ∆ second night vs first night	12.2 (8.2–16.0) 0.7 (–1.9 to 4.7) P=0.670	13.5 (10.0–18.0) 0.5 (–3.6 to 6.4) P=0.443	13.1 (6.8–18.3) –0.1 (–4.3 to 6.2) P=0.735	14.3 (7.7–15.8) 0.8 (–2.7 to 5.3) P=0.390
SWS in percent of TB (first night) ∆ second night vs first night	7.4 (3.7–12.0) 2.2 (–1.1 to 7.0) P=0.079	11.4 (7.6–16.5) 4.0 (–0.6 to 6.4) P=0.070	8.3 (5.8–10.7) 2.8 (1.4–14.1) P=0.028	7.2 (3.8–12.0) 2.1 (0.5–6.7) P=0.008
NREM sleep in percent of TB (first night) ∆ second night vs first night	61.6 (53.0–70.3) 1.3 (–5.4 to 10.3) P=0.943	65.9 (61.1–69.4) 4.0 (–3.6 to 6.9) P=0.177	55.2 (45.9–65.0) 12.5 (4.6 to 14.1) P=0.043	62.7 (58.6–67.2) 5.2 (–5.1 to 7.9) P=0.263
REM latency in minutes (first night) ∆ second night vs first night	75 (58–104) –5 (–28 to 50) P=0.649	86 (49–140) –10 (–63 to 18) P=0.408	83 (38–124) –7 (–53 to 45) P=0.866	79 (55–116) –18 (–38 to 6) P=0.027
SOL in minutes (first night) ∆ second night vs first night	41 (19–51) 13 (–15 to 16) P=0.705	17 (6–25) –1 (–14 to 10) P=0.938	11 (1–21) 5 (–1 to 19) P=0.176	27 (15–52) 0 (–15 to 18) P=0.794

Notes:Significant differences between the second and the first night are marked in bold (P<0.05 Wilcoxon signed-rank test). The results are presented as median results. The numbers in parentheses show the IQR.

Abbreviations:AI, arousal index; AWA, awakening; N1/N2, NREM sleep stage 1/2; NREM, non-REM; PLMD, periodic limb movement disorder; REM, rapid eye movement; RLS, restless legs syndrome; SOL, sleep onset latency; SRBD, sleep-related breathing disorder; SWS, slow wave sleep; TB, time spent in bed; WASO, wake after sleep onset.

Figure 1 In some sleep parameters, age-related changes between the two nights were found.

Notes: In MS patients suffering from insomnia, younger age was correlated with an increased REM latency in the first night (A). In MS patients suffering from PLMD or RLS, older patients spent less time in REM sleep in the first night (B), whereas younger patients needed more time to fall asleep in the first night (C). Older MS patients without any sleep disorder showed a larger decrease in arousal between the first and second night, indicating possible indication for a slight FNE in older patients (D). In summary, the age-related changes were relatively small, and older and younger patients were similarly affected although in various parameters: Amongst MS patients suffering from insomnia or PLMD/RLS, the younger the patient the smaller the REM latency and sleep onset latency. In MS patients without sleep disorders, the older the patients the higher the number of arousal in the first night. But, in general, it cannot be said that older or younger patients showed a more pronounced FNE.
Abbreviations: AI, arousal index; FNE, first night effect; MS, multiple sclerosis; PLMD, periodic limb movement disorder; REM, rapid eye movement; RLS, restless legs syndrome; SOL, sleep onset latency; SRBD, sleep-related breathing disorder; TSiB, time spent in bed.

Table 3 Spearman’s rank correlations of the FNE with age within each subgroup

Spearman’s rank correlation with age (years)		Insomnia (n=17)	No sleep disorder (n=17)	SRBD (n=7)	PLMD/RLS (n=22)
∆ AI (per hour of sleep)	Correlation coefficient	–0.401	–0.517	0.090	–0.276
	P-value	0.111	0.034	0.848	0.214
∆ WASO (minutes)	Correlation coefficient	0.418	–0.004	0.108	0.156
	P-value	0.095	0.987	0.818	0.488
∆ Number of sleep stage changes	Correlation coefficient	0.169	–0.102	–0.324	–0.117
	P-value	0.518	0.696	0.478	0.605
∆ Number of AWAs	Correlation coefficient	0.085	–0.023	–0.477	0.091
	P-value	0.746	0.929	0.279	0.687
∆ SE (% of TSiB)	Correlation coefficient	–0.370	–0.237	–0.180	0.046
	P-value	0.144	0.360	0.699	0.840
∆ NREM sleep 1+2 (% of TSiB)	Correlation coefficient	–0.448	0.121	0.577	–0.302
	P-value	0.072	0.644	0.175	0.171
∆ Slow wave sleep (N3) (% of TSiB)	Correlation coefficient	0.049	–0.228	–0.144	0.053
	P-value	0.851	0.379	0.758	0.813
∆ NREM sleep (% of TSiB)	Correlation coefficient	–0.080	0.002	0.468	–0.191
	P-value	0.760	0.993	0.289	0.394
∆ REM latency (minutes)	Correlation coefficient	–0.620	–0.116	–0.360	0.088
	P-value	0.014	0.670	0.427	0.697
∆ SOL (minutes)	Correlation coefficient	0.286	0.274	–0.450	–0.424
	P-value	0.266	0.286	0.310	0.049
∆ REM sleep (% of TSiB)	Correlation coefficient	–0.068	–0.324	–0.144	0.451
	P-value	0.796	0.205	0.758	0.035

Notes:Changes in sleep parameters between night 1 and night 2 were analyzed. Significant differences between the second and the first night are marked in bold (P<0.05 Wilcoxon signed-rank test).

Abbreviations:AI, arousal index; AWA, awakening; FNE, first night effect; N3, NREM sleep stage 3; NREM, non-REM; PLMD, periodic limb movement disorder; REM, rapid eye movement; RLS, restless legs syndrome; SE, sleep efficacy; SOL, sleep onset latency; SRBD, sleep-related breathing disorder; TSiB, time spent in bed; WASO, wake after sleep onset.