Treating Speech Impairments in Autism with Delayed and Rewarding Feedback: Preliminary Investigation

Background: Speech impairments are very common in autism and many children with severe autism speak unintelligibly or are even mute. Preliminary investigation of few rare cases, who can nevertheless communicate, revealed that at least some of them have difficulty hearing themselves when attempting to speak intentionally. Based on these observations, on the evidence for a tight link between auditory reception and production via auditory feedback in the normally developing brain and on the extensive evidence for abnormal auditory processing in autism, we hypothesize that speech impairments in autism could be at least in part due to abnormal processing of sensory feedback, which is critical for proper development of speech.

Objectives: Investigate and apply altered auditory and visual feedback methods for training a small number of autistic children with unintelligible speech, for which current therapies are not sufficiently effective.

Methods: Two types of feedback were developed: (1) delayed and amplified echo of the speech and (2) visual feedback as an alternative method to reward successful production. The visual feedback was a movie clip, specifically attractive to the child which was activated with speech production. These methods were applied in a clinical setup of a private speech therapy clinic.

Results: Preliminary application of the approach showed significant improvement in verbal production for two young children (ages 3.5, 4.5) with severe autism and severe speech impairment. In addition, it encouraged and motivated the children to produce speech and improve their cooperation with the therapist. The method was also applied successfully to three non-autistic children with severe developmental verbal dyspraxia. One child (age 6) made frequent phonological errors but could not hear these errors during production. We found that he could easily detect the errors when separated in time (2s delayed feedback) and tended to immediately correct himself following the echo. Similar observations were made with two 3-years old children for whom training with the delayed feedback produced significant improvement. These results and observations are only preliminary and should further be investigated.

Conclusions: Development of an altered feedback speech therapy shows a potential and should be further developed and investigated. Future goals include the development of various feedback enhancements that should direct the speaker towards the desired articulation.  If successful, this innovative method would be beneficial for many children with severe autism who are currently unable to speak intelligibly and for which there is no effective therapy.