Effect of Intrathecal Baclofen On Severe Tactile Defensiveness and Symptoms of Autism Spectrum Disorder

Background: This is a case report concerning a teenage patient with Autism Spectrum Disorder (ASD) and mild tactile defensiveness who had a subsequent traumatic brain injury (TBI). Prior to the TBI, the patient was independent in self care and was about to graduate high school after taking special education courses. Post-TBI he developed spasticity and his tactile defensiveness was severely exacerbated. His social and language skills, already impaired because of ASD, were markedly diminished. His severe tactile defensiveness and behavior precluded his participation in physical therapy and severely increased his required level of nursing care. He was referred to the Physical Medicine and Rehabilitation clinic for treatment of spasticity and behavior problems.

Objectives: To report the improvements in tactile defensiveness and autism symptoms that resulted from treatment of spasticity with intrathecal baclofen.

Methods: After several conservative interventions, including oral baclofen, failed to provide significant reduction of spasticity, the patient underwent an intrathecal baclofen trial approximately 19 months after the TBI. During the trial, intrathecal baclofen reduced the patient’s spasticity as desired and the patient also became more tolerant of tactile stimulation. Because of the success of the intrathecal baclofen trial for reducing spasticity, an intrathecal pump system was surgically implanted.

Results: Subsequent to infusion of baclofen by the intrathecal pump system, the patient’s spasticity was significantly improved as expected. Unexpectedly, the patient’s mother, personal care attendants, and the treating physician noted that tactile defensiveness and symptoms of autism exhibited by the patient also were reduced. Prior to the pump implantation, the patient’s progress was severely limited and his level of dependent care was high. After implantation, he demonstrated rapid and marked improvement. Self care tasks that previously required the assistance of two helpers could be done by the patient independently or with minimal assistance. The area of most marked improvement was in the patient’s ability to interact with his environment. The degree to which he became tolerant of external stimulation was excellent. His language and social skills were improved.

Conclusions: Treatment of spasticity resulting from TBI with intrathecal baclofen had the unexpected benefit of also reducing tactile defensiveness and symptoms of ASD. Baclofen is an analogue of the neurotransmitter gamma-amino butyric acid (GABA) and an agonist for GABA receptors. Disruptions in the GABA-ergic system have been hypothesized as a mechanism of ASD. The effect of baclofen on symptoms of ASD is likely due to its action on GABA receptors. Baclofen has anti-nociceptive effects and this may explain its efficacy for reducing tactile defensiveness. Additional patient studies should be conducted to determine if intrathecal baclofen has efficacy for reducing tactile defensiveness and improving social interaction and language skills.