Efficacy and Mechanisms of Virtual Reality Treatment of Phantom Leg Pain

Visual Analogue Scale of McGill Short Form Questionnaire (Melzack, 1987); 0 minimum score - 10 maximum score; higher scores indicate higher level of pain (worse outcome)

McGill Short Form Questionnaire (Melzack, 1987): a series of 4-point scales assessing 15 characteristics of pain (e.g., throbbing, shooting, cramping, etc.). It generates separate scores for Sensory, Affective, and Total pain (maximum 78 points), and correlates strongly with the well-known long form of the questionnaire

average pain intensity since the previous intervention on an 11-point numerical rating pain scale; (0 - minimum score/no pain; 10 maximum score/pain as bad as participants can imagine); higher scores indicate higher level of pain (worse outcome)

The Frenchay Activities Index (FAI) (Holbrook et al., 1983):1983): a scale measuring the physical function and daily activity that has excellent reliability in subjects with lower-limb amputation in predicting quality of life (Asono et al., 2008). 0 minimum score - 45 maximum score; higher scores indicate more daily activities (better outcome).

The 12-Item Short Form Health Survey (SF-12) (Ware et al., 1996): a brief measure of quality of life and functional capacity that has been validated in patients with amputation and PLP (Padovani et al., 2015; Chen et al., 2012; Pape et al., 2010). 0 minimum score - 100 maximum score. Higher scores indicate lower physical and mental health (worse outcome).

The Pain Interference Scale from the Brief Pain Inventory (BPI) (Cleeland & Ryan, 1994): this assesses the degree to which pain interferes with daily activities using a 0-10 numeric rating scale. 0 minimum score - 10 maximum score. Higher scores indicate higher pain interference (worse outcome).

The Hospital Anxiety and Depression Scale (HADS) (Zigmond & Snaith, 1983):1983): the HADS is a 14- item measure assessing both depressive and anxiety symptoms. In addition to providing separate scores for anxiety and depression, the HADS also provides a measure of global negative affect. 0 minimum score - 42 maximum score. Higher scores indicate more depression and anxiety (worse outcome)

The 13-item Pain Catastrophizing Scale (Sullivan et al., 1995): this scale investigates pain catastrophizing, which has been highly associated with pain severity and disability after amputation (Hanley et al., 2004; Whyte & Carroll, 2004; Jensen et al., 2002). 0 minimum score -52; Higher scores indicate higher tendency to catastrophizing (worse outcome)

Insomnia Severity Index (Bastien et al., 2001): this is a 7-point scale that measure insomnia, a symptom associated with PLP (Durmus et al., 2015). 0 minimum score - 28 maximum score; higher scores indicate more insomnia (worse outcome)

Technology Acceptance Scale (Morris et al., 1997): this is a 7-point scale that measure level of acceptance of the VR system. 0 minimum score - 133 maximum score; higher scores indicate low level of acceptance (worse score)

System Usability Scale (SUS) (Brooke, 1996); Scale measuring the usability of each game; minimum score 10 - maximum score 50. Higher scores indicate less usability (worse outcome).

Simulator Sickness Questionnaire (Kennedy et al., 1993);

Brief Slater-Usoh-Steed Presence Questionnaire (Usoh et al., 2000; Slater et al., 1998; 1994). 7 minimum score - 42 maximum score. Higher scores indicate more presence in the VR (better outcome

The Modified Limb Deficiency and Phantom Limb Questionnaire (Goller et al., 2013): this questionnaire assesses prosthesis type and usage and non-painful phantom limb experiences, including perceived position (e.g., telescoping) and ability to move the phantom. In addition to providing useful descriptive information, prosthesis use and telescoping will be used in the adaptive randomization algorithm to assign subjects to treatments.

visual analogue scale that evaluates treatment satisfaction (Robinson et al., 2004; Smith et al., 2005); 0 minimum score - 10 maximum score; Higher scores indicate more treatment satisfaction (better outcome)