SUMMARY It has been hypothesized that non-rapid eye movement (NREM) sleep facilitates declarative memory consolidation, and rapid eye movement (REM) sleep is particularly important in promoting procedural learning. The aim of this study was to examine the effects of pharmacological REM sleep suppression on performance in different neuropsychological tasks. For our baseline, we chose 41 moderately depressed patients (age range 19-44 years), who were not taking antidepressants. In the morning after polysomnography, we tested memory recall and cognitive flexibility by assessment of verbal and figural fluency, a shift of attention task and the Trail Making Test B. After recording baseline values, patients were assigned randomly to one of three treatment groups: medication with citalopram; medication with reboxetine; or exclusive treatment with psychotherapy. Retesting took place 1 week after onset of treatment. The main results were: (1) an association of slow-wave sleep with verbal memory performance at baseline; (2) a suppression of REM sleep in patients taking citalopram and reboxetine; (3) no differences regarding neuropsychological performance within the treatment groups; and (4) no association of REM sleep diminution with decreases in memory performance or cognitive flexibility in patients treated with citalopram or reboxetine. In line with other studies, our results suggest that there are no negative effects of a decrease in REM sleep on memory performance in patients taking antidepressants.k e y w o r d s citalopram, major depression, neuropsychology, reboxetine, REM sleep, slow-wave sleep

Serious neurological complications after diving have increased in the last years because of its increased popularity [1,2,5,7]. Dangerous neurological complications such as ischemic stroke reflecting an acute central nervous system pathology are frequently associated with a dysbaric air embolism or decompression sickness (Caisson's disease), but may also include rarer causes [8]. Due to unspecific clinical presentation, the differential diagnosis of diving-related neurological symptoms may be difficult. A dissection of cervical arteries in young to middle-aged scuba divers has rarely been described. We describe a patient with internal carotid artery dissection after scuba diving, who presented at the emergency department with subacute embolic strokes. In addition, we also summarize the published reports to date of cervical artery dissections associated with scuba diving. Case reportA 51-year-old right-handed man presented with a history of neurological symptoms after having performed a scuba dive in a lake a week earlier. The dive was guided by and performed with a professional diving instructor. The whole dive including pre-and post-diving preparation took 2 h. The uneventful time under water was as follows: 15 min at 5 m, 15 min at 20 m and 15 min at 5 m with a total underwater time of 45 min. The weight of the diving gear did not exceed the usual weight range for recreational diving. There was no trauma during the dive or unusual movements or minor trauma afterwards. He was a certified recreational diver with moderate experience. Three hours after surfacing he noted slurred speech and difficulties finding words for 15 min. After 2 days he noted difficulties with tongue movement and problems with swallowing and expressing words. After that, his food intake was restricted to liquids. He also suffered from an aching throat and leftsided dull temporal-occipital headaches. After 4 days he turned to his GP who initiated further vascular evaluation.On presentation at the Neurological Emergency Unit he showed an incomplete Horner's syndrome with miosis and ptosis on the left eye and dysarthria. He also presented a tongue deviation to the left and a deviation of the uvula. The rest of the neurological examination was normal with no clinical evidence of long-tract disturbances, extrapyramidal or brain-stem dysfunction. No sensory abnormalities, motor deficits or cognitive deficits were observed. The general physical examination revealed normal findings.No relevant past medical or family history could be found. He had smoked 20 cigarettes per day until 1990.The ultrasound of the extra-and intracerebral cerebral vessels showed a resistance profile in the distal extracranial part of the left internal carotid artery. The flow in the left middle cerebral artery was decreased in comparison to the right side, but was collaterally fed via the anterior and posterior communicating arteries and the left (retrograde) ophthalmic artery.