What actually causes alpha intrusion wave sleep, resulting in nonrestorative sleep? cns disorder?

Alpha-NREM sleep: patients with chronic pain syndromes and problems like Fibromyalgia have this kind of sleep problems. Also patients taking sedative-hypnotics. Chronic Rheumatoid Arthritis and chronic fatigue syndrome. It be thought to be hypervigilance and wakefulness or light sleep intruding on the deeper stages of sleep.

Unknown: It occurs when α waves appear with non-REM sleep when δ activity is expected. The clear etiology is unknown, but is commonly seen when fatigued long-term. There is no large body of evidence linking it to sleep disorders, fibromyalgia, chronic fatigue syndrome, or major depression. See a neurology or pulmonary sleep specialist for discussion. http://www.nlm.nih.gov/medlineplus/sleepdisorders.html