Transcranial Magnetic Stimulation to Improve Gesture Control
Condition: Schizophrenia and Related Disorders
MeSH terms: Schizophrenia
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      The majority of schizophrenia patients is impaired in hand gesture performance, which
      contributes to poor functional outcome and poor communication skills. The left inferior
      frontal gyrus (IFG) and the left inferior parietal lobe (IPL) are key nodes of the gesture
      network, which is less active in patients with schizophrenia. Here, the investigators test
      single sessions of rTMS/TBS known to either enhance or inhibit local brain activity for app.
      1 hour. The investigators aim to determine, which protocol may improve gesture performance in
      patients and healthy controls. This is a randomized, double-blind, cross-over,
      placebo-controlled single-center trial in 20 patients with schizophrenia spectrum disorders
      and 20 healthy controls. Gesture performance will be tested immediately after each TMS
      session, which are separated by 48 hours. Results of this study will inform larger
      interventional trials comparing 2 TMS protocols with repeated administration.
    

Detailed description: 
      Schizophrenia is associated with poor social functioning, which is perturbed by deficits in
      social interaction including nonverbal communication. The use of hand gestures is critical
      for nonverbal communication, but the majority of schizophrenia patients has severe gesture
      impairments. Today no intervention may ameliorate gesture impairments. Patients with gesture
      impairments have altered structure and function of the gesture network, particularly the left
      inferior frontal gyrus (IFG) and also the left inferior parietal lobe (IPL). Noninvasive
      brain stimulation techniques may alter local brain function. Repetitive transcranial magnetic
      stimulation (rTMS) and particularly theta burst stimulation (TBS) for a few mins is a very
      safe method to alter brain states locally for approximately 1 hour. Indeed, facilitatory
      stimulation of the left frontal cortex by transcranial direct current stimulation (tDCS)
      demonstrated improved gesture perception and interpretation in healthy subjects. In addition,
      inhibitory stimulation with continuous theta burst stimulation (cTBS) over left IFG may
      perturb gesture performance in healthy subjects. Thus, the investigators hypothesize that
      local changes of brain activity within the gesture network would change gesture performance.
      Particularly, facilitatory intermittent theta burst stimulation (iTBS) of the left IFG would
      improve gesture performance. The investigators will test single sessions of rTMS in healthy
      subjects and schizophrenia patients. If one of the protocols proves to have superior effects,
      this result will help to plan interventional trials targeting social interaction deficits in
      schizophrenia. The aim of the study is to determine the effect of one session of iTBS over
      the left IFG on gesture performance compared to cTBS over the right IPL (active comparator)
      and one placebo rTMS sessions. This is a randomized, double-blind, cross-over,
      placebo-controlled single-center trial in 20 patients with schizophrenia spectrum disorders
      and 20 healthy controls. After baseline assessment of gesture performance, participants will
      receive one rTMS protocol at each time point, immediately followed by assessments of gesture
      performance and dexterity. rTMS sessions will be separated by 48 hours. Gesture performance
      will be measured with video recorded Test of Upper Limb Apraxia, which is rated blindly
      according to a manual.
    

Intervention name(s): left IFG iTBS; right IPL cTBS; Placebo
Intervention type(s): Device; Device; Device
Intervention description(s): 15 daily sessions of intermittent theta burst stimulation at 80% resting motor threshold, total duration of 190 s, localization using EEG 10/20 system at F3/F4; 15 daily sessions of continuous theta burst stimulation at 100% resting motor threshold, total duration of 45 s, localization using EEG 10/20 system at F3/F4; rTMS with a placebo coil that looks identical and makes identical noises for 180 s, localization over left IPL
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: randomized, double-blind, cross-over trial of 3 rTMS protocols
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Treatment
Keywords: gesture; rTMS; nonverbal communication; schizophrenia; psychosis