▸ Motor stereotypies

▸ Self-stimulatory behaviours (eg, compulsive Valsalva manoeuvre leading to reflex anoxic seizures)

▸ Sensory processing issues (eg, unusual visual experiences)

▸ Associated dystonia (repetitive twisting movements)

▸ Status dystonicus

▸ Dyskinetic movement disorders (eg, choreoathetoid movements)

▸ Agitation episodes manifested by hypermotor or tonic spasm features (with or without autonomic accompaniments) due to undiagnosed or undertreated comorbidities that can cause pain such as gastro-oesophageal reflux, constipation, orthopaedic problems, dental pain … etc. Every effort should be made to assess for pain and to rule these causes out

▸ Subcortical myoclonus

▸ Tonic spasms

▸ Paroxysmal autonomic instability with dystonia: tachycardia, hyperthermia, hypertension, agitation and extensor posturing

▸ Timeout phenomenon, in which, the child would appear to be staring blankly and become motionless. This is usually situational. It may be mistaken for absence seizures

▸ Self-stimulatory behaviours (eg, rocking, spinning … etc)

▸ Hand stereotypies

▸ Syncopal attacks secondary to hyperventilation, breath holding and prolonged QT interval

▸ Abnormal behaviours (eg, ‘screaming fits’)

▸ Drop attacks secondary to cataplexy (sudden loss of muscle tone in response to intense emotions like laughter)

▸ Tics and motor stereotypies: can complicate the treatment course with methylphenidate

▸ Oculogyric crisis: presents with dystonic ocular movements such as upward deviation of the eyes, periorbital twitching and prolonged staring. Agents may include domperidone, metoclopramide and carbamazepine

▸ Tardive dyskinesia: characterised by rhythmic movements of the tongue, face, trunk and extremities. Can complicate prolonged treatment (>3 months) with a dopamine antagonist such as risperidone

▸ Status dystonicus secondary to sudden withdrawal of baclofen or benzodiazepines