**3. Diagnosis of parasomnias**

All parasomnias more commonly affect persons who have breathing disorders during sleep. Polysomnography is appropriate for any patient with symptoms or signs of obstructive sleep apnea, such as daytime hypersomnolence, nocturnal hypoxia, loud snoring and increased neck circumference. REM behavior disorder often occurs concomitantly with degenerative neurologic illnesses that may require further evaluation. In adults, the onset of arousal disorders such as somnambulism and night terrors may reflect underlying neurologic disease. Thus, neurologic evaluation, including imaging of the central nervous system, may be indicated (Bornemann et al., 2006).

Diagnosis of parasomnias relies on a comprehensive clinical evaluation. Additional testing with polysomnogram and time-synchronized video recording may be indicated for cases that are associated with very frequent episodes, complaints of excessive sleepiness, unusual presentation, or injury to the individual or bed partner. A formal laboratory sleep study or polysomnogram with an expanded electroencephalographic montage can help distinguish among non-REM and REM parasomnias and nocturnal seizures. The latter may manifest clinically as arousals from sleep associated with vocalization and/or complex behaviours (Farid et al., 2004).
