Use of Hand Prosthesis With Surface Electrical Stimulation for Treatment of Phantom Limb Pain
Condition: Phantom Limb Pain
MeSH terms: Phantom Limb
Study type: Interventional

Summary: 
      Phantom limb pain (PLP) is a frequent consequence of amputation, and it is notoriously
      difficult to treat. Amputation usually follows traumatic injuries or surgery following
      vascular diseases, diabetes, osteomyelitis or tumours in cases where the loss of the limb is
      required for the survival of the patient. The loss of a limb or other body parts is usually
      followed by the sensation that the lost body part is still present and can be felt. These
      phenomena are called, respectively, phantom awareness and phantom sensation. In 50-80% of
      amputees neuropathic pain develops in the lost limb also referred to as phantom limb pain
      (PLP). PLP can be related to a certain position or movement of the phantom limb, and might be
      elicited or worsened by a range of physical factors (e.g. changes in the weather or pressure
      on the residual limb) and psychological factors (e.g. emotional stress). It is well known
      that most treatments available for PLP today, such as pharmacological, surgical, anaesthetic,
      psychological and other, are ineffective.

      Today it is believed that phantom limb pain may be related to changes in the cortex of the
      brain. There is evidence that these changes may be modulated - or even reversed - by
      providing sensory input to the stump or amputation zone. For example, cortical reorganization
      and alleviation of phantom limb pain has been observed in amputees following intense use of a
      hand prosthesis. However, there is no consistent knowledge on which type of peripheral
      sensory feedback may be effective in affecting the cortical plasticity or on how to best
      apply the sensory feedback.

      The aim of the proposed research is to create natural, meaningful sensations through
      providing non-invasive sensory feedback (i.e. surface electrical stimulation) and the
      effectiveness to alleviate phantom limb pain and restore the cortical neuroplastic changes.
    

Detailed description: 
      Purpose of the experiment Up to 50-80 % of persons with amputations experience pain in the
      part of the body that is missing. This phenomenon is called phantom limb pain. It is not
      clear today why phantom limb pain occurs, and since the pain can be difficult to treat, it
      can affect the quality of life. Other scientific studies have shown, that the use of
      electrical stimulation applied through surface electrodes, can assist to decrease or
      alleviate the phantom limb pain. The aim of this study is to investigate if surface
      electrical stimulation for a period of 3 months can decrease or alleviate the phantom limb
      pain.

      Methods Before the study begins, it will be necessary to test if the participant can tolerate
      the electrical stimulation and that the participant fulfill all criteria for participating in
      the study. During the study, different electrical stimulation sequences will be applied. The
      participant will be asked to fill out a series of questionnaires before, during and after the
      electrical stimulation, to describe how the electrical stimulation is experienced, and if the
      stimulation had an effect on the phantom limb pain and phantom sensations. The participant
      will also be asked about their general mood to investigate if this has an effect on the pain.
      The brain signals of the participants will be measured twice with either surface electrodes
      or with a scanning technique, while the participant is thinking about moving the amputated
      arm/hand, while moving the healthy arm, or while receiving electrical stimulation.

      Plan for the experiment The experiment will take place over a period of 3 months and consists
      of a series of measurement and intervention sessions planned in 2 phases (intensive and
      semi-intensive therapy). All sessions will take place at the University Hospital of Lausanne
      (CHUV), Switzerland.

      Visit 0. Interview and meeting with the subject (before the experiment begins, 1 session, 1-2
      hours). Before the experiment begins, the participant is invited to a meeting and interview
      with project responsible to inform the participant about the experiment.

      Visit 1. Preliminary investigations (before the experiment starts, 1 session, maximum 3 hours
      pr session). Before the experiment starts, but after the participant has signed the informed
      consent, the investigators will test if the participant can tolerate the electrical
      stimulation.The evoked sensory feedback sensations over the hand, will be characterized by
      non-invasive, transcutaneous electrical stimulation of the peripheral nerves in different
      locations on the upper limb, both when stimulating single channel per at time, or several
      channels simultaneously. This session will allow to identify the electrical stimulation
      optimal parameters (amplitude, frequency and pulse-width) to induce sensations on the hand
      and how to modulate these sensations, close to natural pattern. A protocol to be integrated
      in a close-loop (bidirectional control) system of artificial hand will be developed. If all
      criteria for participation are fulfilled, the participation of the subject will be decided.

      Week 1 to week 12. Experiments with the superficial stimulation and hand prosthesis control
      (sEH) will then be performed three days per week for up to 3 hours per day according to the
      daily experiment aims and the compliance of the subject. The duration of the experiments will
      be 3 months. sEH will be divided in two different phases:

        1. intensive (from 1st to 6th week) ; during this period the experiments will be carried
           out three days per week;

        2. semi-intensive (from 7th to 12th week); during this period the experiments will be
           carried out one to two consecutive days per week;

      The stimulation protocol will be composed of different programs (Exp):

      The program 1 (Exp1) of the experiment will be performed in order to characterize the best
      positions and parameters for the stimulation. The subjects will provide his/her feedback by
      means of a dedicated psychophysical platform specially designed for this purpose.

      The program 2 (Exp2) will be performed with the aim of trying different combination of
      channels and to identify the best pattern to deliver the most natural and useful sensation.

      After each stimulus is delivered with the different combination of electrodes, the
      participant will provide his/her feedback on the type, strength and location of the sensation
      (if any) through the psychophysical testing platform.

      sEH programs (Exp 3) The investigators will test the possibility to drive the stimulation
      produced by electrical stimulator with the transformed signals from sensors in (or over) the
      robotic hand, which is voluntary controlled by the user.

      If everything works, the investigators will then proceed with the therapeutic use of the
      robotic hand prosthesis. More specifically, they will ask the participant to perform several
      tasks (depending on capacity, availability and motivation):

      i) execution of different force levels ii) Identification of objects physical properties iii)
      Embodiment tests (ownership) iv) Functional improvement tests (activities of daily living):

      Risks, side effects and disadvantages Surface stimulation may cause muscle-contractions.
      Attachment of the surface electrodes may cause the skin to become red or irritated for some
      hours following the experiment. The type of electrical stimulation used in this experiment is
      not associated with any known risks or side effects. When the sensory threshold is determined
      (i.e., the lowest strength of the electrical stimulation that the participant can feel), it
      may feel unpleasant or painful for a short period of time, but the unpleasantness or pain
      will disappear as soon as the electrical stimulation stops. The electrical stimulation
      applied during the intervention period will be adjusted such that is it not painful.

      Measurement of the brain signals using the functional magnetic resonance imaging technique
      (fMRI) is safe, and there are no known risks or side effects of this procedure. The
      participant may, however, find that being placed inside the scanner is unpleasant.
      Measurement of the brain signals with surface electrodes is also considered safe, and there
      are no known risks or side effects of this procedure. There may be risks associated with the
      experiment that are unknown to the investigators. Therefore, the participant are asked to
      inform the investigators if the participant experiences any health problems during the
      experiment. If any side effects are discovered by the investigators, the participant will be
      informed immediately.

      Benefits of the experiment There will be no benefits for the subject by participation in the
      study. However, the participant may find that his/her phantom limb pain is alleviated during
      the experiment as a result of the electrical stimulation. However, it is not possible for the
      investigators to predict if the electrical stimulation will affect the phantom limb pain,
      when the effect will start, how large the effect will be, or how long the effect will last.
      It is not possible to offer the participants a permanent or lasting solution after
      termination of the study.

      Exclusion from and suspension of the experiment If the participant, according to the
      assessment of the investigator, react unexpectedly on the procedures or in any other way are
      not suitable for continuing in the experiment, the participation in the experiment can be
      terminated at any time. In general, the experiment will be terminated if it turns out that
      the subjects in general cannot tolerate the procedures of the project or find the experiment
      too exhausting.
    

Intervention name(s): Surface electrical stimulation
Intervention type(s): Device
Intervention description(s): Surface electrical stimulation using the following experimental devices. 1) The CE-approved HASOMED electrical isolated stimulator (Rehastim). 2) Two hand prosthesis: the robotic hand "Azzurra" (Prensilia, Italy) and the robotic hand "Multi-sensory Prosthetic Hand" (Wessling robotics, Germany) 3) The EPIONE Psychophysical Testing Platform software for stimulator control. Surface stimulation therapy is provided while providing visual guidance to the subject.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Neuroplasticity; Sensory Feedback; Transcutaneous electrical stimulation; Robotic hand