Abstract: Background: 
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Despite motor impairment is not currently included in the diagnostic criteria or evaluation of ASD, there is increasing evidence that subjects with ASD also have motor impairments, including gait alterations. Toe walking (TW) is a possible finding during gait observation in about 20% of subjects with ASD. TW persistence can contribute to a secondary shortening of the Achilles’ tendon. 

Objectives: 
This systematic review aims to summarize the evidence about TW interventions in individuals with ASD. 

Methods: 
The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations and was prospectively registered in the International Prospective Register of Systematic Reviews (registration no.CRD42020176335). The literature search was performed up to July, 24 2020 on Medline (via PubMed), CINAHL, PsycINFO, The Cochrane Library, Google Scholar and Opengrey, from the inception of these databases. No restrictions regarding language, year of publication, and age of population were applied. Two reviewers independently screened titles and abstracts for eligibility; then independently screened full-text of potentially eligible studies. A hand searching of the reference 
list of included studies was also performed (Figure 1). Assessment of the studies’ completeness has been conducted using the CARE checklist. 

Results: 
After the selection process, a total of 7 articles were included. They were all case reports, considering a total sample of 11 subjects (11 males; age range of 4-9 years). Five studies assessed the effectiveness of behavioural interventions using acoustical feedback or tactile stimulus in addition to positive reinforcement. One study proposed serial casting, and the one evaluated the efficacy of a lymphatic drainage technique. In all 7 studies, a reduction of TW frequency has been reported. A follow-up assessment was conducted only in 2/7 studies. 

Conclusions: 
There is a lack of high-quality studies with a sufficiently large and wellcharacterized sample to assess the effectiveness of treatments for TW in individuals.

Notes:

1 - University of Milano-Bicocca
2 - Villa Santa Maria Foundation