A sleep clinic is a specialized medical facility dedicated to the diagnosis and management of conditions that disrupt rest. People seek out these centers when they experience persistent issues such as excessive daytime sleepiness, loud snoring, or unexplained movements during the night. The goal is to accurately identify the source of the sleep disruption, which could range from common disorders like sleep apnea to more complex conditions like narcolepsy or restless legs syndrome.
Starting the Process
The process typically begins with a referral from a primary care physician, leading to a first appointment with a sleep specialist. During this initial consultation, the specialist conducts a thorough review of the patient’s medical history and current symptoms. The focus is on understanding the pattern, duration, and severity of the sleep complaint.
Patients often complete standardized questionnaires, such as the Epworth Sleepiness Scale (ESS), to objectively quantify daytime sleepiness. A score above 10 on the ESS often indicates excessive sleepiness and may signal the need for further investigation. Based on this comprehensive intake, the specialist determines if an in-lab study, a Home Sleep Apnea Test (HSAT), or another diagnostic approach is most appropriate.
The Overnight Polysomnogram
The in-lab overnight study, known as a polysomnogram (PSG), is the definitive assessment for many sleep disorders. The setting is usually a comfortable, private room within the clinic, designed to resemble a hotel room. Upon arrival, a registered polysomnographic technologist begins the process of sensor application.
The technologist applies a network of electrodes to the scalp, face, chest, and limbs to measure various physiological functions simultaneously. Electrodes placed on the scalp record brain wave activity (electroencephalography, or EEG), tracking when the patient falls asleep and moves through the different stages of sleep, including light, deep, and Rapid Eye Movement (REM) sleep. Sensors near the eyes (electrooculography, or EOG) monitor eye movements, while electrodes on the chin and legs (electromyography, or EMG) track muscle tone and leg movements, which can indicate conditions like restless legs syndrome.
Breathing is monitored using several tools to capture a complete picture of respiratory function. A thermistor or nasal pressure transducer is placed near the nose and mouth to measure airflow, detecting any pauses or shallow breathing events. Elastic bands are placed around the chest and abdomen to record the effort the body makes to breathe, even when airflow is blocked. A pulse oximeter is clipped to a finger to continuously measure the oxygen saturation level in the blood throughout the night.
The technologist monitors all data streams remotely from a control room, often observing the patient through an infrared camera. This allows the technologist to intervene if necessary, such as adjusting a sensor or beginning a Continuous Positive Airway Pressure (CPAP) titration if severe sleep-disordered breathing is detected. The goal is to record at least six to seven hours of sleep data, even if the patient does not sleep as well as they do at home, as the objective physiological data collected remains highly valuable for diagnosis.
Interpreting Results and Next Steps
Once the study concludes, the multi-channel recording is processed. A scoring technologist meticulously analyzes the raw data, manually identifying and marking significant events, such as arousals, shifts in sleep stage, respiratory events, and limb movements. This scoring generates specific metrics, including the Apnea-Hypopnea Index (AHI), which quantifies the number of breathing disturbances per hour of sleep.
The scored data is then reviewed and interpreted by the sleep physician, who correlates the objective findings with the patient’s symptoms and medical history to establish a diagnosis. An AHI value of five or greater is typically required to diagnose mild Obstructive Sleep Apnea. Other diagnoses may include Narcolepsy (indicated by a short latency to REM sleep) or Periodic Limb Movement Disorder (characterized by frequent leg movements during non-REM sleep).
During a follow-up appointment, the physician discusses the findings, explaining the sleep architecture and the severity of any discovered disorder. Treatment plans are then tailored to the specific diagnosis. Common interventions for sleep apnea include CPAP therapy (which uses a machine to maintain an open airway) or the use of an oral appliance. Other treatments may involve medication, behavioral adjustments, or lifestyle modifications.