Simmons E(A)-2/page 1
Appendix (E)A-2. Methods: Evaluation of the psychometric properties of the ALSSQOL
All sites collected demographic information and administered the following measures of QOL, function, and strength:
- The ALS-Specific Quality of Life Questionnaire (ALSSQOL) – see Results. This was administered to the patient in interview format by a psychologist, research coordinator, nurse, or trained psychology graduate student, with family members out of the room.
- The McGill Quality of Life Single-Item Scale (MQOL-SIS): This consists of a single question in which patients rate their QOL over the preceding 2 days on a 0-10 scale. This is the first question of the MQOL,1-4 and is being retained as a measure of the patient’s own view of his or her QOL. It appears as the first question on the newly-designed ALSSQOL, although it is scored separately from the rest of the ALSSQOL. To make it consistent with the ALSSQOL, the time frame for which QOL is judged by the patient was changed from 2 days to 7 days.
3. ALS functional rating scale (ALSFRS): This is a 40-point scale consisting of 10 items which assess bulbar, limb, and respiratory function. Scores range from 0 (worst function) to 40 (best function).5
4. Manual muscle testing: Strength in four muscle groups (arm abductors, wrist extensors, hip flexors, and ankle dorsiflexors, corresponding to proximal and distal upper and lower extremity muscle groups) was measured and recorded bilaterally for each patient using the Medical Research Council (MRC) Scale of 0-5. A composite MRC score was calculated for each patient, consisting of the sum of the MRC scores in each of these 8 muscle groups divided by 8. Scores range from 0 (weakest) to 5 (strongest).
At least two sites each collected data using the following additional measures:
1. A second measure of overall QOL, either the SEIQoL-DW (a direct-weighting version of the SEIQoL) or the World Health Organization QOL Instrument – Brief Version (WHOQOL-BREF). The SEIQoL-DW is administered using a standardized semi-structured interview. Individuals name 5 areas of life (cues) considered central to their QOL, determine the level of functioning on each cue, and determine the relative importance of each of these cues to that individual’s QOL (cue weight) by the use of a pie chart with sections whose size the individual can adjust to reflect the relative importance of the cues.6,7 An Index Score is then calculated as the sum of the products across the 5 cues: ∑ (levels x weights), and ranges from 0 (lowest QOL) to 100 (highest QOL). Given the physical limitations imposed by ALS, the SEIQoL-DW’s administration procedures and instructions were modified for patients who were unable to mark the visual analog scale of functioning on each cue, or manipulate the SEIQoL-DW disk independently. The WHOQOL-BREF is an abbreviated 26-item version of the WHOQOL-100. Four domains are assessed: physical health, psychological (including spirituality, religion, and personal beliefs), social relationships, and environment. Scores are calculated for each domain.8
2. Two measures of religion/spirituality, the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Subscale (FACIT-SP-12) and the Idler Index of Religiosity (IIR). The FACIT-Sp-12 is a 12-item measure of spirituality developed for evaluation of QOL in patients with chronic illness.9 Previously called the “Rush Spiritual Belief Module”, the items were developed based on interviews with patients and professionals experienced with cancer, HIV infection, or the care of such illnesses. Respondents endorse the truth of statements provided as they apply to them on a scale ranging from “0” (not at all) to “4” (very much). The IIR is a four-item measure and consists of two items assessing public religiousness and two items assessing private religiousness. Total scores range from 4 (least religious) to 17 (most religious).10
3. A measure of psychological distress, the Brief Symptom Inventory (BSI). This is a 53-item self-report measure of symptoms of psychological distress experienced by both medical and psychiatric patients. Items are rated on a five-point scale measuring degree of distress caused by each symptom (0, not at all; 4, extremely). This measure has nine subscales: somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism.11
References
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