Transcranial Magnetic Stimulation (rTMS) and Autism.
Condition: Autism Spectrum Disorder
MeSH terms: Autistic Disorder; Autism Spectrum Disorder
Study type: Interventional

Summary: 
      In this protocol we aim to use rTMS to better characterize STS role in normal and abnormal
      social cognition. With that purpose, we will measure the effect of inhibitory and excitatory
      rTMS on the fixation time on social scenes (using eye-tracking methodology) or on the ability
      to recognize human voice/sounds.
    

Detailed description: 
      Autism is characterized by severe impairments in verbal and non verbal communication and in
      social interactions. Results from cerebral imaging studies have suggested that abnormalities
      located on the superior temporal Sulcus (STS) level would be implicated in social impairments
      in autism. This abnormalities are both anatomical and functional: 1) rest hypoperfusion
      detected by positron emission tomography (PET); 2) abnormal activation during social tasks
      (fMRI) and 3) structural abnormalities shown on anatomical MRI. The STS is implicated in
      social cognition in normal subjects. Our hypothesis is that these anatomo-functional
      abnormalities would appear very early in brain development and could be one of the first
      steps in the cascade of neuronal dysfunction in autism. Transcranial Magnetic Stimulation
      (rTMS) is a technique which is used in cognitive neuroscience research as well as in
      therapeutic approaches in certain neurological and psychiatry diseases. It consists on
      applying a magnetic impulse on the brain trough the scalp in a non-invasive and painless by
      placing a coil on the surface of the head. This magnetic fields induce an electrical field
      which modifies activity of those neurons inside the magnetic field and induce an
      electrophysiological change in the target area. This process allows a non-invasive
      interaction with the human brain in action during focal stimulations. In cognitive
      neuroscience research, we are interested in the modifications caused by rTMS in cognitive
      performances in order to better precise the functional role of the target region. The
      intensity and the frequency of the impulse can be controlled (frequency <1 Hz = inhibitory
      effect ; frequency > 3 Hz = excitatory effect). The functional characteristics of a given
      region and it's eventual dysfunctions may be identified thank to the abnormalities in
      reactivity and cortical connectivity. The goal of this project is to study inhibitory and
      excitatory effects of rTMS applied to the STS in healthy controls and patients with autism.
      This effect will be measured by two main parameters of social cognition: 1) visual perception
      of social scenes, measured by eye-tracking methodology; 2) auditory perception of human
      voice. We will study 50 healthy voluntaries controls and 50 patients with a non-syndromic
      autism (18 to 25 years old; IQ > 60), diagnosed by DSM-IV and ADI-R. All participants will
      undergo an structural MRI and a rTMS session on the STS. In both cases, the STS will be
      localised based on the structural MRI. The total duration of the rTMS session is about two
      hours. All data will be analysed by the adapted statistical methods. This study will allow a
      better understanding of the role of STS in social cognition in healthy subjects as well as
      it's implication in the social impairments which characterize autism. Finally, the rTMS may
      become, in a near future, a innovative therapeutic strategy in autism.
    

Intervention name(s): Transcranial Magnetic Stimulation (rTMS); Transcranial Magnetic Stimulation (rTMS)
Intervention type(s): Device; Device
Intervention description(s): Excitatory effects of Transcranial Magnetic Stimulation (rTMS) applied to the STS in patients with autism.; Inhibitory effects of Transcranial Magnetic Stimulation (rTMS) applied to the STS in healthy controls
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: TMSAutism; Eye-tracking; Social perception; Social cognition