Differentials
Oromandibular dystonia
SIGNS / SYMPTOMS
Slow, twisting, repetitive muscle spasms that affect the mandible, tongue, and lips.[84] Often associated with dystonia of the neck muscles (cervical dystonia/spasmodic torticollis), eyelids (blepharospasm), or larynx (spasmodic dysphonia). Sleep bruxism can also be present.
INVESTIGATIONS
No differentiating tests. Clinical diagnosis.
Huntington's disease
SIGNS / SYMPTOMS
Hereditary neurodegenerative condition characterised by irregular, unpredictable choreic body movements.[84] Sleep bruxism may also be a feature.
Neurological evaluation identifies characteristic cognitive impairment (e.g., concentration impairment, task apathy, and anxiety), behavioural features (e.g., irritability, impulsivity), and motor features (e.g., chorea, twitching/restlessness, bradykinesia/rigidity).
INVESTIGATIONS
Genetic testing confirms gene with an expanded trinucleotide CAG repeat (the mutant allele).
Tourette's syndrome
SIGNS / SYMPTOMS
Repetitive, irregular, stereotyped, suppressible movements (tics) of the eyes, face, and neck. May occur during light non-rapid-eye movement (non-REM) sleep, sleep stage shifts, and micro-arousals and awakenings.[84]
INVESTIGATIONS
No differentiating tests. Clinical diagnosis.
Hemifacial spasms
SIGNS / SYMPTOMS
Unilateral, non-epileptic twitches of the face also during sleep.[84]
INVESTIGATIONS
Needle EMG shows irregular, brief, high-frequency bursts (150-400 Hz) of motor unit potentials, which correlate with clinically observed facial movements.
Parkinson's disease
SIGNS / SYMPTOMS
Multi-system neurological syndrome characterised by hypokinetic movements due to muscle stiffness and resting tremor. Caused by degeneration of the dopaminergic system. Swallowing difficulties and drooling may persist during sleep, whereas resting orolingual tremor is absent.[84]
INVESTIGATIONS
Dopaminergic agent trial shows improvement in symptoms.
Tardive dyskinesia
SIGNS / SYMPTOMS
Neuroleptic-induced abnormal oromandibular movement disorder eventually associated with sleep bruxism.[84] May feature any or all of movement of the lips and tongue (grimacing, smacking, pursing, sticking out the tongue), rapid blinking, impaired finger movement or 'fluttering', rapid movements of the arms, toe-tapping, moving the leg up and down, twisting and bending of the torso (in extreme cases).
INVESTIGATIONS
No differentiating tests. Clinical diagnosis.
REM-behaviour disorder
SIGNS / SYMPTOMS
Acting out dramatic and/or violent dreams, so may involve limbs. Often involves grunting or shouting. Usually seen in men ≥60 years old.
INVESTIGATIONS
Polysomnographic video recording shows increase in muscle tone associated with the EEG pattern of REM sleep (in contrast to the EEG pattern of REM sleep associated with an absence of muscle tone in healthy individuals). Video shows body movements coinciding with the EEG pattern of REM sleep.
Use of this content is subject to our disclaimer