Abnormal Sleep in Chronic Inflammatory Demyelinating Polyneuropathy

Abstract

Background and objectives: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a dysimmune disease leading to sensorimotor deficits due to peripheral nerve dysfunction, but recently additional non-sensorimotor symptoms (NSMS) were increasingly recognized. In this context, we compared the sleep behavior in persons with versus without CIDP and discussed the results with respect to further NSMS.

Methods: Twenty-five CIDP patients and 27 controls took part in this prospective, cross-sectional study. Clinically, sensorimotor disability (RODS), affective state (DESC-I), and fatigue levels (FSMC scores) were assessed. Regarding sleep-wake behavior, they wore actigraphic devices over 14 consecutive days and completed sleep diaries, chronotype questionnaires, and the Pittsburgh Sleep Quality Index (PSQI). The actigraphic data were analyzed with respect to sleep efficiency, wake after sleep onset (WASO), sleep onset latency, total sleep duration, intradaily variability (IV), and interdaily stability (IS).

Results: Patients with CIDP reported significantly worse subjective sleep quality (p < 0.001). They also showed higher levels of fatigue (p < 0.001) and depressiveness (p = 0.046). The actigraphic results showed significantly reduced WASO (p_bonf = 0.012), especially early in the morning and immediately preceding waking up (p = 0.010). The sleep abnormalities were not linked to the raised clinical data (p > 0.05).

Discussion: Beyond subjectively reduced sleep quality, actigraphic data show that persons with CIDP have lowered sleep efficacy and experience increased nocturnal arousals. This suggests that sleep disturbance is a genuine aspect of CIDP adding to the underrecognized problem of NSMS in this condition.

Keywords: CNS manifestations; chronic inflammatory demyelinating polyneuropathy; fatigue; neurodegeneration; sleep.

FIGURE 1

Comparisons of subjective and objective sleep‐related measures in CIDP patients versus controls. (a–c) Subjective self‐report measures in controls (purple) and CIDP patients (teal), while (d–f) present objective actigraphic metrics over 14‐consecutive days weekends for analysis excluded. Individual dots represent on average value per participants. Horizontal line represents mean and vertical line 95 CI. DESC, Depression Scale; FSMC, Fatigue Scale for Motor and Cognitive Functions; PSQI, Pittsburgh Sleep Quality Index; WASO, Wake After Sleep Onset. *p < 0.05, **p < 0.01, ***p < 0.001.

FIGURE 2

Actigraphy‐derived sleep and activity patterns in CIDP and control participants. (a, b) Individual 24‐h actograms (noon to noon) for a representative CIDP patient (a) and a control subject (b). Light blue shading indicates the estimated sleep interval, and yellow vertical bars denote epochs of wakefulness detected during that sleep period. (c, d) Group‐averaged activity profiles (solid lines) with ±SEM shading for weekday data (noon to noon) in CIDP (c) and controls (d). Dashed lines show cosinor fits. (e, f) Group mean wakefulness (% of time awake) in 1‐min bins over the first 5 h following sleep onset on weekdays (e) and prior to sleep‐offset. Significant clusters (CIDP > Control) were identified from minute 1 to 70 after sleep onset, as well as from 119 until 86 min and 38 until 1 min prior to sleep‐offset (p = 0.010), all indicated by the black horizontal bar. CIDP, chronic inflammatory demyelinating polyneuropathy; h, hours; N, number of weekday nights (panels c, d) or number of participants (panel e); PIM, proportional integrating mode (ActiGraph activity units); R ², coefficient of determination (goodness of fit); SEM, standard error of the mean.

FIGURE 3

Correlation between sleep efficiency and clinical scales in CIDP patients and controls. The top panels (a, c, e) show correlations for the CIDP patient group, while the bottom panels (b, d, e) show the same correlations for the control group. Individual dots represent the value for each participant, the solid line indicates the linear regression, and the shaded area represents the 95% confidence interval. Correlation coefficients (ρ for Spearman's rank) for each comparison are displayed on the individual graphs together with derived p values. CIDP, chronic inflammatory demyelinating polyneuropathy; DESC, Depression Scale; FSMC, Fatigue Scale for Motor and Cognitive Functions; PSQI, Pittsburgh Sleep Quality Index.