Epilepsy and Sleep Disorders relationship may be more complex);15 this may explain the association
of spike-wave discharges with these sleep phenomena. Seizures and epileptiform abnormalities are more commonly seen in transition between sleep stages and also during periods of sleep instability. Indeed, it has been suggested that the increase in spike-wave activity seen after sleep deprivation may be due to more frequent fluctuations in vigilance levels during both wakefulness and sleep.16
The cyclical
In primary generalised and some focal epilepsies (although probably not benign epilepsy with rolandic spikes), interictal discharges are most frequent during CAP phase A than CAP phase B or non-CAP sleep.16,17
alternating patterns (CAPs) seen during NREM sleep have been proposed to be a measure of both changes in sleep states and sleep instability.17
Interaction of Sleep and Seizures
and has often been attributed to antiepileptic medication or seizures. Indeed, unrecognised nocturnal seizures can present as daytime somnolence.19
Excessive daytime somnolence (EDS) is commonplace in patients with epilepsy18
Moreover, patients with more frequent
Patients with epilepsy have an increased number of awakenings during the night and a reduction or fragmentation of REM sleep.20
seizures are more likely to report sleep disturbance than control subjects or patients with less frequent seizures, regardless of epilepsy syndrome.18
Seizures and frequent interictal epileptiform activity can also change sleep architecture, causing more unstable sleep periods as measured with CAPs in both partial and generalised epilepsies.21 Polysomnography following complex partial seizures has revealed a reduced amount of REM sleep after seizures.20
This effect was most
pronounced after nocturnal seizures (from 16 to 7%), but was also significant after seizures occurring the previous day (from 18 to 12%). Nocturnal seizures also reduced the amount of stage II and IV sleep and increased the amount of stage I sleep.20
This was associated with reduced sleep efficiency and increased drowsiness the day after. lobe seizures in a patient with epilepsy and mild OSA.32
Obstructive sleep apnoea (OSA) is over-represented in people with epilepsy, occurring in 10% of people with epilepsy without other neurological or systemic disease.23
However, the major causes of sleepiness in people with epilepsy are co-morbidities such as periodic limb movements and, in particular, sleep apnoea.22
OSA is even more frequent
in people with refractory epilepsy and has been reported in one-third of patients (of whom over one-third have moderate to severe OSA) investigated for epilepsy surgery.24
The risk factors for obstructive
sleep apnoea are the same as in the general population: older age, male gender and obesity.23
OSA fragments sleep and reduces sleep
time, which can have a detrimental effect on seizure control. In older adults with late-onset seizures or worsening of seizure control, OSA is associated with seizure exacerbations.25
In a recent pilot study in patients with Several studies have also
shown an improvement of seizure control after treatment of concomitant OSA.22,26–29
refractory epilepsy and OSA, a 50% reduction in seizures was observed in 28% of treated patients versus 15% of patients in the sham group. Four of 22 patients receiving continuous positive airway pressure (CPAP) treatment and one of 13 receiving sham treatment became seizure-free.27
Epilepsy and antiepileptic drugs may also aggravate OSA. Remission of OSA as well as seizures has been reported in a patient following frontal lobe resection.30
both ictally and, importantly, post-ictally.31
Seizures themselves can result in apnoea Furthermore, an increase
in apnoea–hypopnoea index has been seen after nocturnal frontal EUROPEAN NEUROLOGICAL REVIEW Antiepileptic
drugs can also worsen OSA through sedation, muscle relaxation and weight gain. Non-pharmacological treatment for epilepsy with vagus nerve stimulation has also been shown to worsen OSA.33
Identification
and treatment of both epilepsy and OSA are hence important to optimise patient outcome. Antiepileptic drugs can also have a complex effect on sleep and different drugs can have very varied effects on sleep quality and quantity, ranging from hypersomnolence to insomnia (see Table 1).34
Nocturnal Frontal Lobe Epilepsy and Non-rapid Eye Movement Parasomnia – Diagnosis and Differential Diagnosis Nocturnal frontal lobe seizures can manifest as: paroxysmal arousals, which consist of brief, sudden eye opening, head raising or sitting up in bed, a frightened expression and, sometimes, vocalisation; or nocturnal paroxysmal dystonia, which involves dystonic posturing and hypermotor (complex motor) phenomena, and episodic nocturnal wanderings, which are longer in duration (one to three minutes), with associated stereotyped dystonic movements.35
nocturnal frontal lobe epilepsy (NFLE) will commonly have more than one of these seizure types. Daytime interictal EEG shows epileptiform abnormalities in up to one-third of cases; this increases to 50% of nocturnal EEGs.35
Tachycardia is common during the seizures.35 be difficult to differentiate epileptic arousals from physiological 61 More REM, less deep sleep
As the night progresses so there is less stage 3/4 sleep and a greater proprortion of rapid eye movement (REM) sleep.
Table 1: Effects of Some Antiepileptic Drugs on Sleep Sleep
PB
Efficiency +
PHT 0 CBZ 0 VPA
GBP 0 LTG 0 TPM 0
+ 0
+ 0 0 0
+ + 0
– 0
+ 0
0
– 0 0
+ – 0
– 0 0 0
+ + 0
– 0 0 0
– – 0
– = decrease; + = increase; 0 = no change; CBZ = carbamazepine; GBP = gabapentin; LTG = lamotrigine; PB = phenobarbitone; PHT = phenytoin; REM = rapid eye movement; TPM = topiramate; VPA = valproate. Green represents sleep promotion, while red represents sleep disruption.
Figure 1: Typical Hypnogram Showing Sleep Stages Through the Night
Hypnogram Awake
REM 1
2 3 4
1 2 3 4 567 8 Hours of sleep
Stage 1 Stage 2 Deep REM Arousal Sleep
People with
Ictal EEG is often unhelpful or there may be only subtle features such as electrodecrement or rhythmic frontal slow.35
Although it can
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