Limb movements
Nocturnal myoclonus
Sleep pathology in adults
Definition
It is a sleep disorder characterized by brief involuntary muscle contractions during sleep.
These contractions may be very mild and unnoticed by the person experiencing them, or they may be strong enough to awaken the individual or their partner and cause insomnia.
Nocturnal myoclonus can affect any muscle group, but most often affects the muscles of the legs, arms and torso. The disorder may be idiopathic, meaning there is no known cause, or it may be related to other medical conditions or factors, such as stress, taking certain medications or sleep deprivation.
Symptoms
It is a disorder consisting of abrupt myoclonic jerks of the extremities, lasting 1 to 5 seconds, which appear every 20-40 seconds in the form of outbreaks, during
all night long, causing awakenings and sleep phase changes in the patient.
These discharges can occur in both extremities and also in one leg. The most characteristic movement is dorsiflexion of the foot, combined with partial flexion of the knee and leg.
It is more common to find this type of pathology among the elderly. Elderly sufferers report having a fractionated and superficial sleep, they are easily awakened by any noise, and it is difficult for them to maintain a continuous sleep throughout the night. As a result, they feel very tired during the day, as if they had only slept a few hours.
Diagnosis
It is performed by polysomnography, when there are at least 5 jerks per hour of sleep, each followed by an awakening. This “awakening” is not always a wakefulness, but may simply be a change in the phases of sleep (from deeper to shallower), resulting in a splitting of sleep and causing discomfort the next day.
Myoclonus is recorded during the sleep study, using motion sensors placed on the patient’s heel.
Treatment
Treatment of nocturnal myoclonus depends on the underlying cause and severity of symptoms.
Some treatment options may include improved sleep hygiene, treatment of underlying medical conditions, medications, behavioral therapy such as the use of relaxation techniques and muscle control techniques.