Phantom motor execution in the lower limb aided by myoelectric pattern recognition and virtual reality: A case study on a chronic phantom limb pain sufferer.
Conference poster, 2017
Phantom Motor Execution (PME) facilitated by
Myoelectric Pattern Recognition (MPR) and Virtual
Reality (VR)1 poses itself as an effective treatment for
Phantom Limb Pain (PLP). Notably, a recent clinical
trial using the methodology on a population of 14 upper
limb amputees with intractable chronic PLP showed
statistically significant improvements (approx. 50%
reduction) in all the metrics used to measure PLP2.
This study aimed to assess, for the first time, the efficacy
of PME facilitated by MPR and VR in reducing PLP in
the lower limb.
A 70-years-old male with traumatic trans-femoral
amputation since 35 years on the right side was treated
twice a week, for a total of 23 sessions. Each session
consisted of pre-treatment pain assessment, electrode
placement, PME treatment (2.0 h) and post-treatment
pain evaluation. Pain was assessed in terms of Weighted
Pain Distribution (WPD), Numeric Rating Scale (NRS),
Pain Perception Frequency (PPF) and Short Form of
McGill Pain Questionnaire (SF-MPQ)3.
Moreover, effects on quality of life, disability and
participation levels as well as intrusion of PLP in
activities of the daily living and sleep were monitored.
The PME treatment consisted in using myoelectric
signals produced in stump muscles during phantom
motions in order to control a VR limb. This was made
possible thanks to the MPR system BioPatRec4.
Figure 1 shows the visual representation of WDP as it
is registered at the beginning of each session: a general,
however not complete, reduction of pain can be noticed.
The highest levels of PLP (4 and 5), usually present in
the evening and at night disappeared over time. As a
consequence, length and quality of sleep increase from
2h/night with interruptions to 7h/night undisturbed.
SF-MPQ showed a significant reduction (>50%) in the
number of chosen pain descriptors as well as in the
Pain Rating Index. Quality of life improved drastically:
the patient reported less tiredness, improved mood and
regained ability to drive for long distance (> 200 km at a
time, not possible before). Moderate levels of PLP (1-3
in Figure 1) are still present, accounting for unchanged
score in NRS and PPF.