Background: As an indicator of physical and cognitive functioning in community-dwelling older adults, there is increasing interest in measuring life space, defined as the geographical area a person covers in daily life. Typically measured through questionnaires, life space can be challenging to assess in amnestic dementia associated with Alzheimer's disease (AD). While global positioning system (GPS) technology has been suggested as a potential solution, there remains a lack of data validating GPS-based methods to measure life space in cognitively impaired populations. Objective: The purpose of the study was to evaluate the construct validity of a GPS system to provide quantitative measurements of global movement for individuals with mild-to-moderate AD. Methods: Nineteen community-dwelling older adults with mild-to-moderate AD (Mini-Mental State Examination score 14-28, age 70.7 ± 2.2 years) and 33 controls (CTL; age 74.0 ± 1.2 years) wore a GPS-enabled mobile phone during the day for 3 days. Measures of geographical territory (area, perimeter, mean distance from home, and time away from home) were calculated from the GPS log. Following a log-transformation to produce symmetrical distributions, group differences were tested using two-sample t tests. Construct validity of the GPS measures was tested by examining the correlation between the GPS measures and indicators of physical function [steps/day, gait velocity, and Disability Assessment for Dementia (DAD)] and affective state (Apathy Evaluation Scale and Geriatric Depression Scale). Multivariate regression was performed to evaluate the relative strength of significantly correlated factors. Results: GPS-derived area (p < 0.01), perimeter (p < 0.01), and mean distance from home (p < 0.05) were smaller in the AD group compared to CTL. The correlation analysis found significant associations of the GPS measures area and perimeter with all measures of physical function (steps/day, DAD, and gait velocity; p < 0.01), symptoms of apathy (p < 0.01), and depression (p < 0.05). Multivariate regression analysis indicated that gait velocity and dependence were the strongest variables associated with GPS measures. Conclusion: This study demonstrated that GPS-derived area and perimeter: (1) distinguished mild-to-moderate AD patients from CTL and (2) were strongly correlated with physical function and affective state. These findings confirm the ability of GPS technology to assess life space behaviour and may be particularly valuable to continuously monitor functional decline associated with neurodegenerative disease, such as AD.

1.
May D, Nayak US, Isaacs B: The life-space diary: a measure of mobility in old people at home. Int Rehabil Med 1985;7:182-186.
2.
Peel C, Sawyer Baker P, Roth DL, Brown CJ, Brodner EV, Allman RM: Assessing mobility in older adults: the UAB Study of Aging Life-Space Assessment. Phys Ther 2005;85:1008-1119.
3.
Baker PS, Bodner EV, Allman RM: Measuring life-space mobility in community-dwelling older adults. J Am Geriatr Soc 2003;51:1610-1614.
4.
Uemura K, Shimada H, Makizako H, Yoshida D, Doi T, Yamada M, Suzuki T: Factors associated with life-space in older adults with amnestic mild cognitive impairment. Geriatr Gerontol Int 2013;13:161-166.
5.
Sartori AC, Wadley VG, Clay OJ, Parisi JM, Rebok GW, Crowe M: The relationship between cognitive function and life space: the potential role of personal control beliefs. Psychol Aging 2012;27:364-374.
6.
Barnes LL, Wilson RS, Bienias JL, De Leon CF, Kim HJ, Buchman AS, Bennett DA: Correlates of life space in a volunteer cohort of older adults. Exp Aging Res 2007;33:77-93.
7.
Crowe M, Andel R, Wadley VG, Okonkwo OC, Sawyer P, Allman RM: Life-space and cognitive decline in a community-based sample of African American and Caucasian older adults. J Gerontol A Biol Sci Med Sci 2008;63:1241-1245.
8.
James BD, Boyle PA, Buchman AS, Barnes LL, Bennett DA: Life space and risk of Alzheimer disease, mild cognitive impairment, and cognitive decline in old age. Am J Geriatr Psychiatry 2011;19:961-969.
9.
Stalvey BT, Owsley C, Sloane ME, Ball K: The life space questionnaire: a measure of the extent of mobility of older adults. J Appl Gerontol 1999;18:460-478.
10.
Schenk AK, Witbrodt BC, Hoarty CA, Carlson RH, Goulding EH, Potter JF, Bonasera SJ: Cellular telephones measure activity and lifespace in community-dwelling adults: proof of principle. J Am Geriatr Soc 2011;59:345-352.
11.
Boissy P, Brière S, Hamel M, Jog M, Speechley M, Karelis A, Frank J, Vincent C, Edwards R, Duval C, EMAP Group: Wireless inertial measurement unit with GPS (WIMU-GPS) - wearable monitoring platform for ecological assessment of lifespace and mobility in aging and disease. Conf Proc IEEE Eng Med Biol Soc 2011;2011:5815-5819.
12.
Dubois B, Feldman HH, Jacova C, Dekosky ST, Barberger-Gateau P, Cummings J, Delacourte A, Galasko D, Gauthier S, Jicha G, Meguro K, O'Brien J, Pasquier F, Robert P, Rossor M, Salloway S, Stern Y, Visser PJ, Scheltens P: Research criteria for the diagnosis of Alzheimer's disease: revising the NINCDS-ADRDA criteria. Lancet Neurol 2007;6:734-746.
13.
Nasreddine ZS, Phillips NA, Bédirian V, Charbonneau S, Whitehead V, Collin I, Cummings JL, Chertkow H: The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment. J Am Geriatr Soc 2005;53:695-699.
14.
Rossetti HC, Lacritz LH, Cullum CM, Weiner MF: Normative data for the Montreal Cognitive Assessment (MoCA) in a population-based sample. Neurology 2011;77:1272-1275.
15.
Marin RS: Differential diagnosis and classification of apathy. Am J Psychiatry 1990;147:22-30.
16.
Marin RS, Biedrzycki RC, Firinciogullari S: Reliability and validity of the apathy evaluation scale. Psychiatry Res 1991;38:143-162.
17.
Jasiewicz JM, Allum JH, Middleton JW, Barriskill A, Condie P, Purcell B, Li RC: Gait event detection using linear accelerometers or angular velocity transducers in able-bodied and spinal-cord injured individuals. Gait Posture 2006;24:502-509.
18.
Rowlands AV, Stiles VH: Accelerometer counts and raw acceleration output in relation to mechanical loading. J Biomech 2012;45:448-454.
19.
Tung JY, Semple JF, Woo WX, Hsu WS, Sinn M, Roy EA, Poupart P: Ambulatory assessment of lifestyle factors for Alzheimer's disease and related dementias. AAAI Spring Symposium: Computational Physiology, AAAI, 2011, pp 50-54.
20.
Xue QL, Fried LP, Glass TA, Laffan A, Chaves PH: Life-space constriction, development of frailty, and the competing risk of mortality: the Women's Health and Aging Study. I. Am J Epidemiol 2008;167:240-248.
21.
Njomboro P, Deb S: Poor dissociation of patient-evaluated apathy and depressive symptoms. Curr Gerontol Geriatr Res 2012;2012:846075.
22.
Robert PH, Mulin E, Malléa P, David R: Review: apathy diagnosis, assessment, and treatment in Alzheimer's disease. CNS Neurosci Ther 2010;16:263-271.
23.
Landes AM, Sperry SD, Strauss ME: Apathy in Alzheimer's disease. J Am Geriatr Soc 2001;49:1700-1707.
24.
Levy ML, Cummings JL, Fairbanks LA, Masterman D, Miller BL, Craig AH, Paulsen JS, Litvan I: Apathy is not depression. J Neuropsychiatry Clin Neurosci 1998;10:314-319.
25.
Feil D, Razani J, Boone K, Lesser I: Apathy and cognitive performance in older adults with depression. Int J Geriatr Psychiatry 2003;18:479-485.
26.
Kuzis G, Sabe L, Tiberti C, Dorrego F, Starkstein SE: Neuropsychological correlates of apathy and depression in patients with dementia. Neurology 1999;52:1403-1407.
27.
Starkstein SE: Syndromic validity of apathy in Alzheimer's disease. Am J Psychiatry 2001;158:872-877.
28.
Kaye J, Matteck N, Hayes T, Austin D, Dodge H: Community life withdrawal with MCI progression. Alzheimers Dementia 2012;8:P483.
29.
Shoval N, Wahl HW, Auslander G, Isaacson M, Oswald F, Edry T, Landau R, Heinik J: Use of the global positioning system to measure the out-of-home mobility of older adults with differing cognitive functioning. Ageing Society 2011;31:849-869.
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