Annals of African Medicine

: 2015  |  Volume : 14  |  Issue : 2  |  Page : 103--108

Sleep disturbances among patients with epilepsy in Nigeria

Morenikeji A Komolafe1, Taofiki Ajao Sunmonu2, Olubunmi A Ogunrin3, Jimoh O Disu2, Birinus A Ezeala4, Sani A Abubakar5, Emmanuel Iwuoso5,  
1 Department of Medicine, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun, Nigeria
2 Department of Medicine, Federal Medical Centre, Owo, Ondo, Nigeria
3 Department of Medicine, University of Nigeria Teaching Hospital, Benin, Edo, Nigeria
4 Department of Medicine, University of Nigeria Teaching Hospital, Enugu, Nigeria
5 Department of Medicine, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna, Nigeria

Correspondence Address:
Taofiki Ajao Sunmonu
Department of Medicine, Federal Medical Centre Owo, Ondo


Background: There is a complex inter-relationship between sleep disorders and epilepsy, and there are few studies in Nigeria on sleep disorders in epilepsy. This study was carried out to determine the prevalence, pattern and predictors of sleep disturbances among persons with epilepsy (PWE). Materials and Methods: This was a multi-center, cross-sectional study of 124 PWE in Nigeria. A questionnaire was used to collect data on social and demographic variables, epilepsy- related variables and sleep disturbances in PWE. Exclusion criteria were mental retardation, and use of sedative drugs. The data was analyzed using Statistical Package for Social Sciences version 11.0 and P < 0.05 was considered as significant. Results: There were 77 males and 47 females with a mean age of 33.4 ± 13.1 years. The mean age of seizure onset was 23.7 ± 14.6 years, while the mean duration of epilepsy was 9.5 ± 9.4 years. The commonest type of epilepsy was secondarily generalized tonic-clonic seizures (62%). The prevalence of sleep disorders in PWE was 82%. Parasomnias occurred in 46%, followed by obstructive sleep apnea in 23%, insomnia (19%) excessive daytime sleepiness (EDS) (17%), and restless leg syndrome (11%). None of the socio-demographic or epilepsy- related variables was predictive of EDS or parasomnias in PWE (P > 0.05). Conclusion: There is a high frequency of sleep disorders among PWE. Clinicians should screen PWE for sleep disturbances.

How to cite this article:
Komolafe MA, Sunmonu TA, Ogunrin OA, Disu JO, Ezeala BA, Abubakar SA, Iwuoso E. Sleep disturbances among patients with epilepsy in Nigeria.Ann Afr Med 2015;14:103-108

How to cite this URL:
Komolafe MA, Sunmonu TA, Ogunrin OA, Disu JO, Ezeala BA, Abubakar SA, Iwuoso E. Sleep disturbances among patients with epilepsy in Nigeria. Ann Afr Med [serial online] 2015 [cited 2020 Sep 18 ];14:103-108
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Full Text


Epilepsy is the most common noninfections neurological disease in developing countries. [1],[2] Sleep disorders are common; snoring has been reported in a third of the general population, while parasomnias occur in a quarter to two-thirds of Nigeria adult population. [3],[4],[5] The frequency of sleep disorders has been observed to be higher in persons with epilepsy (PWE). In particular, excessive daytime sleepiness (EDS), insomnias and parasomnias, [6],[7],[8] were observed to be common and could result in cognitive impairment and poorly controlled seizures.

In sub-Saharan Africa, myths, misconceptions are common in epilepsy and contribute to late presentation for orthodox medical care. Similar misconceptions have been observed in sleep disorders. For instance, any unusual occurrence during sleep is usually attributed to the nocturnal warfare caused by spiritual enemies, and this is described as "Ogun Oru." [9] There has been no previous work on the occurrence of sleep disorders among PWE in Nigeria and hence we carried out this cross-sectional study to determine the prevalence, pattern and predictors of sleep disturbances among PWE.

 Materials and Methods

This was a cross-sectional, multi-center study carried out among PWE from five tertiary health care centers in Nigeria. The study sites were the neurology clinics of Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, and the Federal Medical Centre, Owo located in South-West Nigeria, the University of Benin Teaching Hospital, Benin in the South-South, University of Nigeria Teaching Hospital, Enugu in the South-East and Ahmadu Bello University Teaching Hospital, Zaria in the North-Central zone. A questionnaire was used to collect information on demographic variables, epilepsy related variables and sleep disturbances among the study participants; the questionnaire had been validated in a previous study. [3] Information on epilepsy related variables was also documented. Patients with cognitive defects, patients with known psychiatric co-morbidity and use of hypnotic drugs were excluded from the study. Informed consent was obtained from the patients and approval obtained from the Research Ethics Committee of the participating centers. Verbal consent was also obtained prior to administering the questionnaire.

Case definitions

Epilepsy was diagnosed and classified according to International League Against Epilepsy criteria. [10] Patients with EDS had an Epworth sleepiness score of ≥10. Clinically suspected obstructive sleep apnea (CSOSA) was defined in accordance with the 2001 International Classification of Sleep Disorder, Revised (ICSD-R): Habitual and loud snoring, witnessed apneas and EDS. [11]

Parasomnia was defined according to ICSD-R as undesirable physical events, experiences that occur during entry into sleep, within sleep or during arousal from sleep. [11] Disorders of rapid eye movement (REM) sleep include nightmares, isolated sleep paralysis and REM sleep behavior disorder. Disorders of non-REM (NREM) sleep includes sleepwalking, sleep terrors and confusional arousal, while disorder of sleep-wake transition include sleep talking and sleep starts. Other parasomnias include enuresis, sleep-related dissociative disorder, sleep-related groaning, sleep-related hallucinations etc. [11]

Restless leg syndrome (RLS) was defined according to ICSD-R as an irresistible urge to move the legs usually accompanied or caused by unpleasant sensation in the legs and this worsens during the period of lying down or sitting. The unpleasant sensation is relieved by movement of the legs. This condition is not better explained by another sleep disorder, medical or neurological disorders, mental disorder, medication use or substance abuse disorder. [11]

Statistical analysis

The data were analyzed using Statistical Package for Social Sciences (SPSS) version 15.0 (SPSS Inc. Chicago IL) Bivariate analysis was performed using Pearson's Chi-square test for categorical variables, and Student's t-test was used to compare the means of continuous variables. Logistic regression analyses were done to determine the predictive factors for the occurrence of EDS and parasomnias in the PWE. The level of significance was 0.05.


Demographic profile

There were 124 subjects comprising 77 males and 47 females PWE. The mean age in years was 33.4 ± 13.1 with a range of 18-70 years. Among the study population, majority were Yorubas (52%), while the other ethnic groups were Hausa's (17%), Ibo's (18%), while other minority groups were (13%). [Table 1] shows the background social and demographic profile of the study participants.{Table 1}

Epilepsy related variables

The mean age of seizure onset was 23.7 ± 14.6 years. The mean duration of epilepsy in years was 9.5 ± 9.4. Majority of PWE's had secondarily generalized tonic-clonic seizures (62%) followed by complex partial seizures (34%). One hundred and thirteen patients (91%) were on anti-epileptic drugs (AEDs) and the range of drug dosages were as follows; carbamazepine, 100-1800 mg/day, phenytoin, 100-300 mg/day and phenobarbitone, 30-60 mg/day. [Table 2] shows other epilepsy-related variables.{Table 2}

Prevalence of sleep disorders in persons with epilepsy

One hundred and two (82%) PWE comprising 63 males (62%) and 39 females (38%) had one or more sleep disorders. The average total sleep time was 7.8 h/day. Twenty-nine PWE reported a sleep time of below 6 h/day, while a total sleep time of >10 h/day was reported by nine PWE. The prevalence of various sleep disorders in the study participants is shown in [Table 3]. The commonest sleep disorders was parasomnias (46%), followed by OSA (23%), insomnia (19%), EDS (17%) and RLS (9%).{Table 3}

There was no relationship between the sociodemographic or epilepsy-related variables and the presence of EDS or parasomnias. [Table 4] highlights the logistic regression analysis result of the relationship between these variables and presence of EDS.{Table 4}


Patients with epilepsy are at a higher risk for sleep disorders, due to nocturnal seizures altering sleep organization and architecture. Some types of seizures are facilitated by specific sleep stages. In general, seizures are likely to occur during NREM sleep. [12],[13],[14] The effect of sleep on the occurrence of epilepsy was described earlier by some workers. [15],[16] The sleep disorders identified were CSOSA, RLS, parasomnias, EDS and insomnia.

Touchon et al.[17] showed that insomnia is very common in PWE. In a prospective study of 100 PWE [7] sleep maintenance insomnia was reported in 52% while 34% had sleep onset insomnia. This figure was higher than the 13% and 7% observed in PWE in this study. A Greek study [18] showed a prevalence of 24% for insomnia in PWE which was also higher than what was observed in this study. The reason for a lower figure in this study might be due to the small sample size of the study.

The incidence of OSA in general population is 4-7%, [19] while the incidence of OSA in patients with refractory epilepsy may be as high as 33%. [20] In highly selected PWE that were referred for polysomnography (PSG), 77% were shown to have OSA in a study. [21] The prevalence of CSOSA in this study was 23% which is similar to that of 15% observed in an Italian study which utilized a structured apnea questionnaire to evaluate PWE. We had no facility for PSG. Patients with co-morbid epilepsy and OSA in previous studies were more likely to be men, overweight and have their first seizures later in life. [22]

Periodic limb movement disorder is characterized by periodic episodes of repetitive and highly stereotyped limb movements during sleep. [22] In study by Malow et al. 35% of PWE [21] had features of RLS using PSG. In the study by Khatami et al.[7] symptoms of RLS were present in 18% of PWE. In this study the prevalence of RLS in PWE was 9%, a lower prevalence rate, probably because PSG, which is more sensitive for detection of RLS, was not done due to nonavailability of this facility at the time of study.

Excessive daytime sleepiness is also common among PWE and may be a direct result of the disease. The prevalence of EDS ranged from 18% to 50% in adult PWE in previous studies. [24],[25],[26],[27] In our study, we observed a frequency of 17% for EDS, which is similar to the findings from these earlier studies. EDS could be due to insufficient sleep at night following obstructive apnea, [20],[21],[22],[23],[24],[25],[26],[27],[28] presence of other co-morbid sleep disorders such as narcolepsy and periodic limb movement syndrome, or side effect of AEDs. [28] In this study, gender, age, type and number of AEDs were not associated with presence of EDS, which is similar to the findings in other previous studies. [7],[18],[26],[27],[28],[29] In this study, the neck circumference was not associated with EDS, which is different from what was observed in a previous study [30] and the reason for this discrepancy is not clear at the moment and need to be explored in a large scale polysomnographic study in the future.

Parasomnias typically occur in association with deeper NREM sleep stages usually in the first one-third of the night. [31],[32],[33] The second type of parasonmias occur in REM sleep and includes nightmares, sleep paralysis and REM sleep behavior disorders, which are observed during the final one-third of the night. [34],[35] Previous studies carried out by Oluwole, [4] and Ohaeri et al., [5] demonstrated that parasomnias particularly nightmares were common among the general population in Nigeria. Multiracial studies in USA also observed that parasomnias are more common among African-Americans compared to Caucasians and that traumatic events were associated with an increased frequency of parasomnias in the population [36],[37] In this study, the prevalence of parasomnias in PWE was 46% which was consistent with the findings from the previous studies. [4],[5] The prevalence of parasomnias in this study is higher than that reported by Busulli et al., [37] who observed that 34% of patients with nocturnal frontal lobe epilepsy had NREM parasomnias and that of Manni et al., [38] with a prevalence of 10% for REM sleep behavior disorder in elderly subjects with epilepsy. In the previous study carried out by Oluwole [4] among medical student's, increased duration of sleep and alcohol intake were associated with parasomnias, while smoking, intake of caffeinated drink and male gender were not associated with parasomnias. Though there is a paucity of literature on the risk factors that were predictive of the presence of parasomnias in PWE however in this study, none of the sociodemographic or epilepsy-related variables predicted the occurrence of parasomnias in the PWE, the reasons for this finding are unclear but might probably be due to possibility of differences in risk factors that could predispose the general population and PWE to development of parasomnias.


Sleep disorders are common among PWE in Nigeria. Further studies are needed to determine the effect of sleep disturbances on quality of life of PWE. Neurologists and general medical practitioners should always inquire about the presence of sleep disturbances in PWE.


In this study, PSG could not be done in any of the study centers because of nonavailability of a sleep laboratory. A follow-up study would be done in the near future with the availability of PSG facilities in these patients.


The authors wish to thank Dr. Adewole O. O. (Department of Medicine, Obafemi Awolowo University Ile-Ife, Osun, Nigeria) for supplying the sleep questionnaire that was used for this study and Dr. Akin Omisore of Department of Community Health, Osun State University, Osogbo, Nigeria for assisting with the statistical analysis.


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