As per this article, https://www.ncbi.nlm.nih.gov/pubmed/12499712 insomnia is a common complaint after ischemic stroke. Why does ischemic stroke leads to insomnia ?
Sometimes, stroke may be associated with insomnia, not because of the brain tissue damage, but because of how it affects someone's life.
Importantly researchers found that although sleep efficiency was reduced in patients, total sleep time between the groups was similar, suggesting that lesions in the brains' centres for sleep-wake regulation are unlikely to cause the insomnia. Rather researchers believe that sleep problems experienced by stroke patients are due to a number of contributory factors, such as greater psychological strain, pain and discomfort as well as reduced levels of physical activity.
The article What happens to sleep after a stroke? (Medscape) describes how different stroke locations can result in different types of insomnia:
- A pontine stroke may be expected to affect REM sleep.
- Particular lesion sites have been reported to cause narcolepsy, destruction of normal circadian sleep/wake patterns, and regional loss. of sleep spindles, but also loss of dream life, a peculiar bed-prone behavioral stereotypy, and visual hallucinations.
- Subcortical strokes affecting basal ganglia may be more associated with excessive daytime sleepiness.
- Immediately after a hemispheric stroke, REM sleep abnormalities are more common. Over a period of weeks after a hemispheric stroke, it is common to observe reduction in total sleep time, sleep efficiency, and sleep stages.
- In one study of hemispheric strokes, one third of stroke patients slept more.