Using Smartphone Sensor Technology to Characterize Ambulatory Patterns of Participants With Peripheral Artery Disease

In the Walking Impairment Questionnaire distance subcategory, participants are asked to rate the degree of difficulty walking specific distances on a scale from 0 to 4. A score of 0 indicates the inability to walk the distance specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).

In the Walking Impairment Questionnaire speed subcategory, participants are asked to rate the degree of difficulty walking one block at specific speeds, ranging from walking slowly to jogging, on a scale from 0 to 4. A score of 0 indicates the inability to walk the distance specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).

In the Walking Impairment Questionnaire stair-climbing subcategory, participants are asked to rate the degree of difficulty climbing a specified number of stair flights, ranging from 1 to 3 stair flights, on a graded scale of 0 to 4. A score of 0 indicates the inability to climb the flights specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).

The SF-36 has eight scaled subscores (Vitality, Physical functioning, Bodily pain, General health perceptions, Physical role functioning, Emotional role functioning, Social role functioning, Mental health). These subscores are weighted sums of the questions in each section. Scores range from 0 - 100. Lower scores = more disability, higher scores = less disability.

The SF-36 has eight scaled subscores (Vitality, Physical functioning, Bodily pain, General health perceptions, Physical role functioning, Emotional role functioning, Social role functioning, Mental health). These subscores are weighted sums of the questions in each section. Scores range from 0 - 100. Lower scores = more disability, higher scores = less disability.

PADQOL is a 38-item survey assessing the quality of life of PAD patients. Items are scored on a scale of 1 (strongly agree) to 6 (strongly disagree). Total scores are sums of all 38 items with a range of 38 (normal quality of life) to 228 (quality of life is severely impaired).

The Ankle Brachial Index (ABI) calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure at the arm. Values between 1.0 and 1.4 are considered clinically normal while lower scores indicate greater progression of vascular disease with scores less than 0.5 indicating severe PAD.

Participants will walk in a 50-foot corridor at the hospital. Maximal walking distance achieved in 6 minutes is recorded in feet. Decreased walking distance indicates increased impairment due to PAD.

Participants will walk in a 50-foot corridor at the hospital. Claudication onset time is recorded in seconds. Decreased time for claudication onset indicates increased impairment due to PAD.

Participants will walk in a 50-foot corridor at the hospital. Claudication onset distance is recorded in feet. Decreased walking distance before claudication onset indicates increased impairment due to PAD.

The SPPB is a group of measures including balance, gait speed, and chair stand. In the balance sub test, patients are awarded points for holding a position for a longer period of time. The balance sub score is a summed value ranging from 0 to 4.

In the gait speed sub test, patients are awarded points for walking a set distance in less time. The gait speed sub score ranges from 1 (time > 8.7 sec) to 4 (time < 4.82 sec) for a 4-meter distance and 1 (time > 6.52 sec) to 4 (time < 3.62 sec) for the 3-meter distance.

In the chair stand sub test, patients are asked to stand from a sitting position. The chair stand sub score ranges from 0 (unable to complete 5 chair stands or completes stand in >60 sec) to 4 (chair stand time is 11.19 sec of less).

The SPPB total score is an unweighted sum of the 3 sub scores, with possible total scores ranging from 1 to 12. Higher scores indicate better function.