Accessing the Unspoken: A Systematic Review on the Use of Psychophysiology in Research on Persons With Severe or Profound Intellectual Disabilities.

BACKGROUND

Accessing the emotional experiences of individuals with severe or profound intellectual disabilities is difficult. Physiological measures offer a promising way to bypass communicative, cognitive, and motor limitations in this population. Yet this emerging field lacks a comprehensive overview of methods used, variables studied, and potential values and pitfalls.

METHOD: A multidatabase systematic review (2008-2025), pre-registered in PROSPERO (ID: CRD42024629708), was conducted following JBI and PRISMA guidelines. From 5495 records, studies were screened at title, abstract, and full-text levels, assessed with MMAT, and synthesized narratively.

RESULTS

Thirty-four studies met criteria, using methods such as eye-tracking, wearable sensors, infrared thermography, and electroencephalography to examine attention, social-emotional processing/engagement, and emotional responses.

CONCLUSIONS

This review provides the first broad synthesis of psychophysiological research in this specific population, outlining methodological and practical considerations and supporting future physiological research aimed at enhancing person-centred care and quality of life.