Limb Laterality Recognition Score: A Reliable Clinical Measure Related to Phantom Limb Pain.

Objective: To explore the usefulness of the limb laterality recognition score as a clinical measure of phantom limb pain, regarding test-retest reliability and association of limb laterality recognition scores with phantom limb pain measures.

Design: Retrospective cohort.

Setting: Community support group.

Subjects: Eleven adults who averaged 4.8 years since lower limb amputation due to vascular pathologies (N = 9), trauma (N = 1), and cancer (N = 1).

Methods: Subjects self-reported amputated limb pain using the sensation subsection of the Prosthetic Evaluation Questionnaire and back and sound limb pain. Using numbered iPads that corresponded to the self-reports, subjects played the Recognise Foot game to assess limb laterality recognition ability. Subjects identified the laterality of 20 foot images, within two seconds each. The software collected accuracy and speed scores in basic, vanilla, and context conditions for two rounds in random order. Basic showed feet against black backgrounds, vanilla showed feet with various monochromatic backgrounds, and context showed feet in clothed or environmental contexts. So that greater accuracy in less time meant a better score, accuracy scores were divided by completion speed. Intraclass correlation coefficient (ICC)3,1 assessed test-retest reliability. Correlations between accuracy/speed and phantom limb pain measures were assessed with Spearman's rho (categorical) and Pearson coefficients (continuous).

Results: Accuracy/speed test-retest reliability was strong (ICC = 0.72) and inversely associated with phantom limb pain frequency (context rho = 0.72).

Conclusions: Limb laterality recognition accuracy/speed in the context condition had good test-retest reliability and correlated strongly with phantom limb pain frequency. Accuracy/speed limb laterality recognition ability relates to phantom limb pain and may be a valid clinical or research measure.