TMS and Attentional Bias in Functional Motor Disorder
Condition: Conversion Disorder
MeSH terms: Motor Disorders; Conversion Disorder; Hysteria; Dissociative Disorders
Study type: Interventional

Summary: 
      Functional motor disorders, also called motor conversion disorder, are common reasons for
      attendance at neurology outpatient clinics. Patients with functional motor disorders are more
      common than patients with multiple sclerosis and have similar levels of disability but more
      psychological morbidity.

      There is limited evidence for effective treatments in functional motor disorders. A small
      number of studies of transcranial magnetic stimulation (TMS), a painless method of cortical
      stimulation, have reported improvement in functional weakness after this treatment including
      in patients with symptoms of several years duration. The Investigators intend to trial TMS in
      a group of 40 patients with functional motor disorder, randomising patients to immediate or
      delayed treatment and therefore comparing a single session of TMS with routine clinical care.
      The Investigators will also ask patients to undergo tests of attentional focus in a cognitive
      neuroscience laboratory - these experiments will be analysed separately from TMS trial data.
    

Detailed description: 
      A randomised non-blinded controlled study design will be used, with 3 months of treatment as
      usual as the control condition and a single session of TMS as the treatment condition.

      40 patients with functional unilateral upper limb weakness will be recruited from neurology
      and neuropsychiatry clinics in Edinburgh and randomised to either immediate treatment or to 3
      month delay during which they will receive routine clinical care. Randomisation will be
      performed using computerised random number generator by a person not involved with the study.

      Patients randomised to delay will complete baseline measures of disability and motor function
      including SF36, modified Rankin score and study specific questionnaires, and will repeat
      these after 3 months. Patients undergoing immediate treatment will complete the same
      questionnaires immediately before and 3 months after treatment. All individuals receiving TMS
      treatment will undergo tests of grip strength and tapping frequency immediately before and
      after treatment.

      The treatment and experiments involved will be as follows. Patients will attend the PPLS
      Cognitive Neuroscience Laboratory at George Square, University of Edinburgh for a single 2
      hour session. During the first hour they will complete baseline symptom severity and
      disability questionnaires and will undertake a series of 3 experiments. Experiments involve
      participants sitting with their head on a chin-rest looking at either a computer screen or at
      lights projected onto their own hands, and for one experiment with a vibrating 'buzzer' taped
      to each hand. They will be asked to respond verbally in experiments which test their response
      to distracting attentional 'cues' either visual or vibrotactile. These experiments will take
      less than 1 hour. In anaylsis, performance will be compared between affected and unaffected
      sides (ie left hand and right hand), and will also be compared with performance of a group of
      15 healthy control participants recruited from spouses or partners.

      Patient participants will then receive treatment with 20 single pulses of TMS to the motor
      cortex at 120% motor threshold. These will cause visible and palpable 'jerks' of the affected
      limb. Between stimulations the researcher will offer verbal encouragement and ask the
      participant to move the affected limb if possible. Treatment will take less than 1 hour.

      The primary outcome measures are patient-rated symptom severity and disability and simple
      statistical analysis will be used to compare outcome after 3 months of treatment as normal
      and 3 months after a single session of TMS treatment. Secondary outcome measures include grip
      strength and tapping frequency before and after treatment. Data will be analysed on an
      intention-to-treat basis. Data from attentional tests will be analysed separately.
    

Intervention name(s): Transcranial magnetic stimulation
Intervention type(s): Procedure
Intervention description(s): Single pulse TMS - 20 pulses at 120% motor threshold. Using the Magstim rapid 2 stimulator, which has a CE mark and will be used within the indications specified by the CE mark.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Adult; Humans; Conversion disorder; Somatoform Disorders/therapy; Nervous System Disorders/therapy