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 .
this relationship is well documented in primary headache disorders , particularly in chronic headache sufferers as compared to episodic variety
. 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 . among the many sleep disorders described in the international classification of sleep disorders , insomnia , daytime sleepiness , and obstructive sleep apnea including snoring
insomnia had been suggested as an independent risk factor for chronification of headache . increased snoring incidence had been observed in chronic headache sufferers compared to episodic ones .
sleep disordered breathing was found to be associated with migraine but not with tension headache .
these disorders are commonly left under diagnosed and when treated helps in better control of headache .
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 , few had studied tension - type headache , and very few both .
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 .
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 ) .
these patients were evaluated by history , clinical examination , sleep questionnaires , and overnight psg study .
clinical details regarding total disease duration , headache type , location , character , duration of attack , and severity were assessed .
the epworth sleepiness scale ( ess ) was used for assessment of excessive daytime sleepiness , and a score of 10 or more was considered abnormal .
sum of individual 's response in eight different situations over a scale of 03 is total score .
each patient was asked about difficulty falling asleep , intermittent night arousals , and early morning awakenings .
the patient was asked to respond according to usual perceivement felt on most of the days ( 4 ) of week .
any positive reply was given a score of 1 , making total score range of 03 .
all the patients were explained prior about the procedure of study and risks involved . the patient was asked to report in the night after washing hairs that morning .
the overnight recording was performed using  somnologica  software ( embla systems , broomfield , co , usa ) .
the recording was continued till the patient wakes up which is  lights on  time .
the recording analysis was done according to the american academy of sleep medicine guidelines 2007 .
the characteristics noted were time in bed , total sleep time , sleep efficiency , sleep onset latency , duration of sleep stages , apnea 
hypopnea index ( ahi ) , periodic limb movement index ( plmi ) , isolated limb movement index ( ilmi ) , number of awakenings , oxygen saturation , and heart rate .
statistical analysis was done using spss software of windows version 16.0 ( chicago , il , usa ) .
all categorical variables were expressed as percentages , and continuous variables were expressed as mean  standard deviation .
clinical details regarding total disease duration , headache type , location , character , duration of attack , and severity were assessed .
the epworth sleepiness scale ( ess ) was used for assessment of excessive daytime sleepiness , and a score of 10 or more was considered abnormal .
sum of individual 's response in eight different situations over a scale of 03 is total score .
each patient was asked about difficulty falling asleep , intermittent night arousals , and early morning awakenings .
the patient was asked to respond according to usual perceivement felt on most of the days ( 4 ) of week .
any positive reply was given a score of 1 , making total score range of 03 .
the overnight recording was performed using  somnologica  software ( embla systems , broomfield , co , usa ) .
the recording was continued till the patient wakes up which is  lights on  time .
the recording analysis was done according to the american academy of sleep medicine guidelines 2007 .
the characteristics noted were time in bed , total sleep time , sleep efficiency , sleep onset latency , duration of sleep stages , apnea  hypopnea index ( ahi ) , periodic limb movement index ( plmi ) , isolated limb movement index ( ilmi ) , number of awakenings , oxygen saturation , and heart rate .
statistical analysis was done using spss software of windows version 16.0 ( chicago , il , usa ) .
all categorical variables were expressed as percentages , and continuous variables were expressed as mean  standard deviation .
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 4144 months .
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 ) .
the mean iss and ess score of all patients were 0.73 ( 0.9 ) and 5.35 ( 3.23 ) , respectively .
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 .
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 .
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 .
comparison of polysomnographic parameters among patients with / without symptom of sleep disturbances : mean ( standard deviation )
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 .
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 . in psg ,
ctth had more stage n3 sleep with lesser awakenings that is better sleep quality in comparison to cm group .
as de gennaro et al . 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 .
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
our study group was population attending hospital opd , thus more of chronic and severe sufferers .
calhoun and ford 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 .
 objective : studies related to sleep disorders and polysomnography ( psg ) among chronic daily headache patients are rare . 
 we studied this and compared chronic migraine ( cm ) with chronic tension - type headache.methods:eighty-three patients were recruited . 
 they were evaluated by semi - structured interview , headache , and sleep diaries along with epworth sleepiness scale score and insomnia symptom score . 
 overnight psg was performed and data compared.results:chronic tension - type headache was more common than cm , both having female preponderance . 
 insomnia followed by excessive daytime sleepiness was prevalent sleep disorder . 
 sleep efficiency and stage 3 sleep were lower in cm compared to chronic tension - type . 
 esss was significantly increased among chronic tension - type patients . 
 no significant correlation was found among psg parameters in patients with or without sleep disorders.conclusion:insomnia being most common sleep disorder among chronic headache population . 
 chronic tension - type headache had slightly better slow - wave sleep than cm and significantly increased daytime sleepiness . 
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Evaluation
Sleep questionnaire assessment
Overnight polysomnography evaluation
Statistical analysis
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Financial support and sponsorship
Conflicts of interest