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Phantom Limb Pain

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Phantom movements and pain -an fMRI study in upper limb amputees A Functional magnetic resonance imaging (fMRI) experiment was conducted on 14 upper limb amputees who were being compared and assessed with seven fully competent participants. This experiment involved examining the execution of hand and lip movements and imagined movements of the phantom limb or left hand. Fourteen of the participants had part of their upper limb amputated, nine of which had lost their right hand. During the experiment, nine of the participants experienced phantom limb pain. Phantom limb pain is unknown however; it is believed that there is a reorganisation in the primary somatosensory cortex into the area that formerly represented the amputated extremity. The purpose of this study was to investigate whether the mental imagination of executed hand movement of the phantom limb pain relates in any way to cortical reorganisation.

Methods
The fMRI study consisted of executed movements by the patients using their able hand, the pulsing of the lip and the imagined mental movements with the amputated hand, for example making a fist shape.

Firstly, EMG recording was used prior to the fMRI experiment to avoid the patients using muscle activity during the imagine movement task and to get them familiar to what to expect from the study. The training was completed when participants showed a vividness imagination of the movement of the phantom limb and scored four out of a possible six on the scale; this was measured against a rest period to determine the function of the ipsilateral cortex in PLP patients.

Secondly, all subjects performed lip-pursing movements. A metronome measured the pace of the lip movements at the rate of 0.5 Hz, which included a rest period also, which was then continued with a further six scans. This measured the cortical reorganisation from face to hand area in motor somatosensory representational maps when performed, against when at rest.

When the...