Study of Sleep Disorders and Polysomnographic Evaluation among Primary Chronic Daily Headache Patients

INTRODUCTION

Headache and sleep have a complex interrelationship with each other.[1] Many headache sufferers complaint that headache leads to sleep disruption in them while on the other hand, inadequate sleep leads to increased frequency, severity, and chronicity of headache.[23] This relationship is well documented in primary headache disorders, particularly in chronic headache sufferers as compared to episodic variety.[13]

Chronic daily headache (CDH) comprises a group of headache disorders occurring at least 15 days per month for 3 or more consecutive months. Around 5% of the normal population suffers from CDH.[4] Among the many sleep disorders described in the International Classification of Sleep Disorders,[5] insomnia, daytime sleepiness, and obstructive sleep apnea including snoring have been linked to chronic headache.[6] Insomnia had been suggested as an independent risk factor for chronification of headache.[7] Increased snoring incidence had been observed in chronic headache sufferers compared to episodic ones.[8] Sleep disordered breathing was found to be associated with migraine but not with tension headache.[9] These disorders are commonly left under diagnosed and when treated helps in better control of headache.[10]

Polysomnography (PSG) is used for objectively assessing sleep macro- and micro-architecture and aids in detecting sleep disorders. The majority of the earlier studies had studied migraine population,[1112] few had studied tension-type headache,[13] and very few both.[1415] The data on chronic headache type is very sparse.

We performed the study to evaluate subjectively and objectively sleep disorders in patients of primary CDH. A secondary subgroup analysis was performed in between chronic migraine (CM) and chronic tension-type headache (CTTH) patients and polysomnographic variables among them were compared.

METHODS

This was a prospective, hospital-based observational study carried out at our tertiary care hospital over a span of 2 years from October 2013 to December 2015. 83 patients of primary CDH were selected from patients attending outpatient department (OPD). Patients were diagnosed by the International Classification of Headache Disorder-3 beta classification.[16] These patients were evaluated by history, clinical examination, sleep questionnaires, and overnight PSG study. The Institutional Ethical committee approval was obtained for the study. Written informed consent was taken from all patients.

RESULTS

The mean age of patients was 31.57 ± 10.26 years. Female patients were more than male (female = 69.9%, male = 30.1%). The mean duration of headache of all patients was 24.99 (±20.72) months, with a range of 4–144 months. Mean severity of headache was 4.23 (±1.42).

Out of total 83 patients, 50 (60.2%) were diagnosed as CTTH, 31 (37.3%) as CM, and only 2 (2.4%) were of chronic cluster headache (CCH). Both CCH patients were male, and one had complaint of insomnia. Forty-two patients had complaints of sleep disturbance either insomnia or daytime sleepiness. Four patients complained of snoring. The mean ISS and ESS score of all patients were 0.73 (±0.9) and 5.35 (±3.23), respectively.

Our main results had been summarized in Table 1. Since CCH patients were only two, we statistically compared CM patients with CTTH. Both CM and CTTH patients had complaints of insomnia (14 vs. 20, P = 0.65) and daytime sleepiness (1 vs. 20, P < 0.05). CTTH had more of ISS (0.86 vs. 0.55, P = 0.16) and ESS score (3.61 vs. 2.06, P < 0.05). Average sleep duration diary and prolonged sleep onset latency (>30 min) were comparable into two groups.

Table 1 Demographic, headache, and sleep-related data including questionnaire for all patients: Counts or mean (standard deviation)

Table 2 summarizes the comparison of polysomnographic parameters among CM and chronic tension-type headache. Total sleep time, sleep efficiency, stage N3 sleep, and rapid eye movement sleep was prolonged in CTTH group though not statistically significant. Sleep onset latency, awakenings per hour, and wake time was more in CM group but not statistically significant. ILMI, PLMI, AHI, desaturation index, and heart rate were comparable among the two groups.

Table 2 Comparison of polysomnographic parameters among chronic migraine and chronic tension-type headache patients: Mean (standard deviation)

Table 3 summarizes the PSG parameters comparison among those complaining of sleep disturbance with those having no complaints. Total sleep time, sleep efficiency, stage N3 sleep, and sleep onset latency were comparable statistically among the groups along with ILMI, PLMI, AHI, heart rate, and O₂ saturation.

Table 3 Comparison of polysomnographic parameters among patients with/without symptom of sleep disturbances: Mean (standard deviation)

DISCUSSION

We studied 83 cases of CDH subjectively by history and questionnaire while PSG provided objective sleep parameters. Among those, more than half were of tension-type and females being more commonly affected which is similar to general population data. Nearly, half complained of sleep disturbances, insomnia being more common than excessive daytime sleepiness. Sancisi et al.[7] in his study found similar results. Increased prevalence of insomnia among headache sufferers had been described in the previous studies.[1]

Both CM and CTTH groups were comparable. Both ISS and ESS score were more in CTTH group with ESS score statistically significant. Sleep diaries revealed comparable average sleep duration and PSG showed comparable total sleep time and sleep onset latencies into two groups. It is well known that chronic insomniacs not always have poor EEG sleep.[19] In PSG, CTTH had more stage N3 sleep with lesser awakenings that is better sleep quality in comparison to CM group.[20] As De Gennaro et al.[21] in his study showed decreased arousals with increased slow wave sleep after sleep deprivation, our PSG findings could indicate more of sleep deprivation among chronic tension-type headache compared to CM.

Various PSG parameters such as ILMI, PLMI, AHI, and desaturation index did not differ significantly. Similar observation was found by Kristiansen et al.[12]

Certain limitations were in our study. We did not have control group in our study, but that is also the strength of study, for the first time a study comparing two major divisions of CDH had been performed. Second, we did not have follow-up of patients. A study design with repeating PSGs on follow-up probably will be more powerful. There was lack of gender matching among the groups. Our study group was population attending hospital OPD, thus more of chronic and severe sufferers.

CONCLUSION

Patients of CDH suffer from sleep disturbances, which are mainly subjective than objective. CTTH patients had marginally increased incidence of insomnia and excessive daytime sleepiness than CM. Calhoun and Ford[10] in his study, over migraine patients found that patients who received behavioral sleep therapy are more likely to revert to episodic migraine. Thus, earlier evaluation and timely management of these may help in better control of headache, improving its outcome, and possibly preventing chronification.[22]