A mains electricity (AC-powered) device designed to record physiological signals from a sleeping patient to assess sleep disorders (e.g., insomnia, snoring or sleep apnoea). The device is typically computerized and usually records an electrocardiogram (ECG), electroencephalogram (EEG), chest wall motion, airflow at both the nose and the mouth, eye movements, haemoglobin oxygen saturation (SpO2) and electromyogram (EMG). Parameters may be added or omitted depending on the study being performed. The device includes multiple electrodes/sensors placed on the patient in specific areas as well as amplifiers and filters for recording.