Non-epileptic paroxysmal events in Rett syndrome: A systematic review of case-based and observational evidence

To systematically review and characterize the spectrum of non-epileptic paroxysmal events in individuals with Rett syndrome (RTT).

We conducted a descriptive systematic review of observational evidence. Searches were conducted across the PubMed, Embase, and OVID databases for studies published from January 1962 to September 2024. Eligible studies included case reports, case series, cohort studies, and small clinical trials that described non-epileptic events in individuals with clinically or genetically confirmed RTT. Data were extracted on study design, participant characteristics, and event types. Events were categorized into respiratory, neuromotor, and behavioural domains.

Sixty-two studies met the inclusion criteria, representing a wide age range of individuals with RTT. The most frequently reported paroxysmal non-epileptic events were respiratory disturbances, including breath-holding and hyperventilation, followed by vacant spells, involuntary movements, and behavioural episodes such as agitation and inappropriate laughter. Discrepancies were noted between the diagnostic attribution of clinician-reported and family-reported events. The term 'Rett episodes' was used by a minority of authors.

A wide range of non-epileptic paroxysmal events requiring different treatment approaches are experienced by patients with RTT. Enhancing clinician awareness and developing clearer diagnostic frameworks are key to improving classification accuracy and preventing unnecessary treatment.