Ipse de Bruggen

Introduction The sleep–wake rhythm in older adults with intellectual disabilities (IDs) is often unstable and fragmented (Maaskant et al. 2013). The instability and fragmentation are associated with sleep problems (Van De Wouw et al. 2012; Van De Wouw et al. 2013), which are found in up to 72% of this population (Van De Wouw et al. 2012; Van De Wouw et al. 2013) and are more common in people with IDs than in their typical developing peers (Surtees et al. 2018; Böhmer et al. 2020; Browne et al. 2024).

For 30 years, Phelan and co-workers described a syndrome characterised by neonatal hypotonia, global developmental delay, strongly impaired speech, sleep disturbances and hyperreactivity to sensory stimuli. This Phelan-McDermid syndrome (PMS), also presenting with symptoms from the autism spectrum and a higher risk of developing seizure disorders, may be caused by a deletion of chromosome 22q13 or by a mutation in the SHANK3 gene.