[Polysomnography (PSG) for studying sleep disorders].

Background: Sleeping problems are very common, and many patients need a comprehensive assessment with polysomnography, possibly followed by a sleep latency test. These methods and indications for the tests are described below.

Method: The article is based on the authors' own literature archives, clinical experience and Retningslinjer for metoder i klinisk neurofysiologi [Guidelines for methodology in clinical neurophysiology]

Results: Polysomnography involves monitoring sleep through the course of one night and scoring the stages of sleep on the basis of EEG activity, eye movements and muscular tension.

Nerve conduction, visual evoked responses and electroretinography in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

The study examines possible persisting effects on the peripheral nervous system and visual system in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. We compared neurophysiological function in 44 tunnel workers previously exposed during grouting operations (2-10 years post exposure), with 49 tunnel workers with no history of exposure to acrylamide. Nerve conduction velocities (NCV), distal delay, F-response and amplitude in median and ulnar nerves of the right arm, peroneal, sural and tibial nerves of the right leg, visual evoked response (VER) and electroretinography (ERG) were measured.

Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

Objectives: The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work.

Material And Methods: Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2-10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group.

CSF hypocretin-1 levels and clinical profiles in narcolepsy and idiopathic CNS hypersomnia in Norway.

Objective: To evaluate the relationship between CSF hypocretin-1 levels and clinical profiles in narcolepsy and CNS hypersomnia in Norwegian patients.

Method: CSF hypocretin-1 was measured by a sensitive radioimmunoassay in 47 patients with narcolepsy with cataplexy, 7 with narcolepsy without cataplexy, 10 with idiopathic CNS hypersomnia, and a control group.

Results: Low hypocretin-1 values were found in 72% of the HLA DQB1*0602 positive patients with narcolepsy and cataplexy.

Effects on the peripheral nervous system of tunnel workers exposed to acrylamide and N-methylolacrylamide.

Objectives: This study evaluates the possible toxic effects on the peripheral nervous system of tunnel workers exposed to acrylamide and N-methylolacrylamide during grouting work.

Methods: Symptoms and nerve conduction velocities (NCV) were recorded for 24 tunnel workers 4 and 16 months after the cessation of exposure during grouting operations. Fifty tunnel workers not involved in grouting operations served as referents.