Inclusion of Participants With Limited English Proficiency in Autism Research.

A systematic review of original research articles published in four autism journals (Autism, Autism Research, Journal of Autism and Developmental Disorders, Research in Autism Spectrum Disorders) between 2013 and June 2025. The team retrieved 1,007 studies from Scopus and PubMed, then screened them in two rounds (title/abstract, then full text) using a 10-person research team trained on the Covidence platform. Inclusion required: original empirical research, human subjects, U.S.-based, and enrollment of autistic people or their caregivers. Of 326 studies that met criteria, 61 included LEP participants. The team then extracted data on languages included, oral and written communication methods, and study design.

Of 326 eligible studies, 61 (19%) included LEP participants. Inclusion was not steadily increasing: it rose from 8% in 2013 to 35% in 2018, held at 32% in 2019, dropped to 14% in 2023, and rose to 27% in 2025. Only 18% of randomized controlled trials included LEP participants. Spanish was the most common non-English language (70% of LEP-inclusive studies), followed by Korean (7%) and German (7%). For oral communication, 24 of 31 studies that specified a method used a bilingual team member, while only 2 used professional interpreters. For written materials, 54% used team-created surveys; 13 used translated existing instruments, of which only 3 were validated in that language. Over half of the studies (51%) did not specify how they determined a participant's preferred language.

The 18% RCT figure means most motor and sensory intervention evidence for ASD has not been tested in LEP populations. If you are citing RCTs to justify a treatment plan for an LEP autistic patient, that evidence base likely did not include people like them.

The same evidence gap applies to OT interventions: only 18% of randomized trials included LEP participants, so the RCTs underpinning your practice for autistic patients may not reflect their language or cultural context.

The paper notes that ASD interventions focus heavily on communication and that using an interpreter adds a layer of difficulty for autistic individuals who may struggle with abstract language, tone, and nonverbal cues. Combined with the 18% RCT figure, this means the communication-intervention evidence you rely on is unlikely to have been tested with LEP autistic patients, and the interpreter-mediated delivery model may not match how your patient actually communicates.

Only four autism-specific journals were reviewed, excluding studies published in broader-scope journals that may be important to the field. The review is limited to U.S.-based research, so findings do not apply to other national contexts where language access needs differ. Many studies that included LEP participants did not specify which languages were involved, so the reported language distribution may be incomplete. Supplemental materials and appendices were not reviewed due to volume, so some communication details may have been missed. The review did not assess immigration status, documentation status, or other structural barriers that affect LEP inclusion. The term 'limited English proficiency' is acknowledged by the authors as ambiguous and deficit-framing; language proficiency is rarely objectively quantified in the studies reviewed.

Do not conclude that the vast majority of autism studies actively excluded LEP participants. The 19% figure is a floor, not a true count: the authors state that many studies likely included LEP participants without reporting it. Separately, the 18% RCT figure means evidence has not been generated in LEP populations. It does not mean interventions are ineffective for them.