Slowness Therapy Shows Promise in Children With Autism Spectrum Disorder

A cute young boy interacts playfully with his instructor who is wearing scrubs and a face shield. They are having a therapy session in which the boy improves his developmental and/or language skills.
Input slowing is based on the temporal theory of ASD that hypothesizes the audiovisual world changes too fast for children with ASD.

“The world often goes too fast for children with autism spectrum disorder (ASD) to process,” according to the authors of a recent assessment of slowness therapy published in the Journal of Autism and Developmental Disorders. In their blinded, longitudinal, randomized, controlled study, they evaluated the impact of a method of input slowing in children with ASD over a 12-month period, concluding that the approach yielded meaningful benefits.

Input slowing is based on the temporal theory of ASD that hypothesizes changes in audiovisual stimuli are too rapid for people with ASD, especially children, making it difficult for them to perceive and integrate information. Therefore, slowing the information may help them process it.

The researchers recruited 23 children (20 boys and 3 girls; median age, 5.8 years [range, 3 to 8 years]) who met the ICD-10 criteria for autism or Asperger syndrome and the DSM-5 criteria for ASD; 87% of the children had moderate to severe autism. For 12 months, the children were randomly assigned to a target group who participated in weekly 45-minute speech therapy sessions using slowness therapy or to a control group who received weekly speech therapy without slowness therapy.

Slowness therapy was administered via Logiral, which is software that simultaneously slows down visual and auditory signals with very good synchrony and little to no distortion. Speech therapists were instructed how to customize the optimum speed for each participant based on how the individual child reacted to different presentation speeds.

All of the children were assessed on communication, imitation, facial emotion recognition, behavior, and face recognition at both the start and end of the study.

The researchers found inappropriate behavior decreased over time in the target group but not in the control group. Two eye-tracking measures (targeting the eyes and mouth regions of a speaker) improved over time in the target group but not in the control group. Three measures of communication as well as facial recognition improved in both groups.

The investigators emphasized that while improvements in communication and facial emotion recognition improved in both groups, “imitation increased, inappropriate behaviors decreased, and time spent fixating [on] mouth and eyes increased solely in the group using slowness. Slowness therapy seems very promising for ASD children.”

One possible limitation of this study, the researchers said, is related to the composition of the groups. The children in the target group “had slightly higher scores [in verbal mental age and adaptive communication and socialization levels] … than children in the control group, which could at least partly be due to the presence of [1] more child with mild ASD and no developmental delay in the target group than in the control one.”

“Slowness opens up new therapeutic avenues that seem effective, progressive and safe for improving face exploration, communicative and imitative skills, and behaviors in children with ASD,” the researchers concluded. “In the same vein, other professionals such as psychomotor therapists, orthoptists, psychologists, educators, teachers, [and] social workers could also easily use slowness (in [an] ecological way and/or through digital tools) during their verbal and social interaction with children and adults with ASD. More largely, slowness could be used by the parents in everyday life playing and learning contexts with their child.”


Gepner B, Charrier A, Arciszewski T, Tardif C. Slowness therapy for children with autism spectrum disorder: a blind longitudinal randomized controlled study. J Autism Dev Disord. Published online July 15, 2021. doi:10.1007/s10803-021-05183-6