936
Views
7
CrossRef citations to date
0
Altmetric
Original Articles

The mediating role of depression in the association between disability and quality of life in Alzheimer's disease

, &
Pages 163-172 | Received 18 Mar 2015, Accepted 05 Jul 2015, Published online: 29 Oct 2015

References

  • Alden, D., Austin, C., & Sturgeon, R. (1989). A correlation between the Geriatric Depression Scale long and short forms. Journal of Gerontology, 44, 124–125. doi:10.1093/geronj/44.4.P124
  • Alexopoulos, G.S., Raue, P.J., Kiosses, D.N., Mackin, R.S., Kanellopoulos, D., McCulloch, C., … Areán, P.A. (2011). Problem-solving therapy and supportive therapy in older adults with major depression and executive dysfunction: Effect on disability. Archives of General Psychiatry, 68, 33–41. doi:10.1001/archgenpsychiatry.2010.177
  • Ball, V., Snow, A.L., Steele, A.B., Morgan, R.O., Davila, J.A., Wilson, N., … Kunik, M.E. (2010). Quality of relationships as a predictor of psychosocial functioning in patients with dementia. Journal of Geriatric, Psychiatry & Neurology, 23, 109–114. doi:10.1177/0891988710363709
  • Baron, J., & Kenny, D.A. (1986). The moderator-mediator variable distinction in social psychological research conceptual, strategic and statistical considerations. Journal of Personality & Social Psychology, 51, 1173–1182. doi:10.1037//0022-3514.51.6.1173
  • Bjørkløf, G.H., Engedal, K., Selbæk, G., Maia, D.B., Coutinho, E.S., … Helvik, A.S. (2015). Locus of control and coping strategies in older persons with and without depression. Aging & Mental Health, 8, 1–9. doi:10.1080/13607863.2015.1040722
  • Boström, G., Conradsson, M., Rosendahl, E., Nordström, P., Gustafson, Y., & Littbrand, H. (2014). Functional capacity and dependency in transfer and dressing are associated with depressive symptoms in older people. Clinical & Interventional Aging, 9, 249–256. doi:10.2147/CIA.S57535
  • Bowling, A., Rowe, G., Adams, S., Sands, P., Samsi, K., Crane, M., … Manthorpe, J. (2015). Quality of life in dementia, a systematically conducted narrative review of dementia-specific measurement scales. Aging and Mental Health, 19, 13–31. doi:10.1080/13607863.2014.915923
  • Brod, M., Stewart, A.L., Sands, L., & Walton, P. (1999). Conceptualization and measurement of quality of life in dementia: The dementia quality of life instrument (DQoL). Gerontologist, 39, 25–35. doi:10.1093/geront/39.1.25
  • Brown, P.J., Devanand, D.P., Liu, X., & Caccappolo, E. (2011). Alzheimer's disease neuroimaging initiative. Functional impairment in elderly patients with mild cognitive impairment and mild Alzheimer disease. Archives of General Psychiatry, 68, 617–626. doi:10.1001/archgenpsychiatry.2011.57
  • Bruvik, F.K., Ulstein, I.D., Ranhoff, A.H., & Engedal, K. (2012). The quality of life of people with dementia and their family carers. Dementia & Geriatric Cognitive Disorders, 34, 7–14. doi:10.1159/000341584
  • Chiao, C., Weng, L.J., & Botticello, A. L. (2011). Social participation reduces depressive symptoms among older adults: An 18-year longitudinal analysis in Taiwan. BMC Public Health, 11, 292. doi:10.1186/1471-2458-11-292
  • Cipher, D.J., & Clifford, A. (2004). Dementia, pain, depression, behavioral disturbances, and ADLs: Toward a comprehensive conceptualization of quality of life in long-term care. International Journal of Geriatric Psychiatry, 19, 741–748. doi:10.1002/gps.1155
  • Clare, L., Kinsella, G.J., Logsdon, R., Whitlatch, C., & Zarit, S.H. (2011). Building resilience in mild cognitive impairment and early-stage dementia: Innovative approaches to intervention and outcome evaluation. In B. Resnick, L.P. Gwyther, & K.A. Roberto (Eds.), Resilience in aging (pp. 245–259). Springer Science+Business Media. doi:10.1007/978-1-4419-0232-0
  • Clare, L., Nelis, S.M., Quinn, C., Martyr, A., Henderson, C., Hindle, J.V., … Victor, C.R. (2014). Improving the experience of dementia and enhancing active life - living well with dementia: Study protocol for the IDEAL study. Health and Quality of Life Outcomes, 12, 164. doi:10.1186/s12955-014-0164-6
  • Cohen, J., Cohen, P., West, S.G., & Aiken, L.S. (2003). Applied multiple regression/correlation analysis for the behavioral sciences (3rd ed.). Mahwah, NJ: Erlbaum.
  • Conde-Sala, J. L, Garre-Olmo, J., Turró-Garriga, O., Vilalta-Franch, J., & López-Pousa, S. (2010). Differential features of burden between spouse and adult child caregivers of patients with Alzheimer's disease: An exploratory comparative design. International Journal of Nursing Studies, 47: 1262–1273. doi:10.1016/j.ijnurstu.2010.03.001
  • Conradsson, M., Littbrand, H., Boström, G., Lindelöf, N., Gustafson, Y., & Rosendahl, E. (2013). Is a change in functional capacity or dependency in activities of daily living associated with a change in mental health among older people living in residential care facilities? Clinical Interventions in Aging, 8, 1561–1568. doi:10.2147/CIA.S53270
  • Conradsson, M., Rosendahl, E., Littbrand, H., Gustafson, Y., Olofsson, B., & Lövheim, H. (2013). Usefulness of the Geriatric Depression Scale 15-item version among very old people with and without cognitive impairment. Aging & Mental Health, 17, 638–645. doi:10.1080/13607863.2012.758231
  • de Boer, M.E., Hertogh, C.M., Dröes, R.M., Riphagen, I.I., Jonker, C., & Eefsting, J.A. (2007). Suffering from dementia – the patient's perspective: A review of the literature. International Psychogeriatrics, 19, 1021–1039. doi:http://dx.doi.org/10.1017/S1041610207005765
  • Formiga, F., Mascaro, J., & Pujol, R. (2005). Inter-rater reliability of the Barthel index. Age and Ageing, 34, 655–656. doi:10.1093/ageing/afi209
  • Gerety, M.B., Williams, J.W., Mulrow, C.D., Cornell, J.E., Kadri, A.A., Rosenberg, J., … Long, M. (1994). Performance of case-finding tools for depression in the nursing home: Influence of clinical and functional characteristics and selection of optimal threshold scores. Journal of American Geriatrics Society, 42, 1103–1109. doi:10.1111/j.1532-5415.1994.tb06217.x
  • Giebel, C.M., Sutcliffe, C., & Challis, D. (2015). Activities of daily living and quality of life across different stages of dementia, a UK study. Aging & Mental Health, 19, 63–71. doi:10.1080/13607863.2014.915920
  • Gómez-Gallego, M., Gomez-García, J., & Ato-García, M. (2014) Confirmatory factor analysis of the quality of life in Alzheimer's disease scale in patients with Alzheimer's disease. Experimental Aging Research, 40, 266–279. doi:10.1080/0361073X.2014.896664
  • Gómez-Gallego, M., Gómez-Amor, J., & Gómez-García, J. (2011) Validación de la versión española de la escala QoL-AD en pacientes con enfermedad de Alzheimer, cuidadores y profesionales sanitarios [Validation of the Spanish version of the QoL-AD Scale in Alzheimer disease patients, their carers, and health professionals]. Neurologia, 27, 4–10. doi:10.1016/j.nrl.2011.03.006
  • Gómez-Gallego, M., Gómez-Amor, J., & Gómez-García, J. (2012). Determinants of quality of life in Alzheimer's disease perspective of patients, informal caregivers, and professional caregivers. International Psychogeriatrics, 24, 1805–1815. doi:10.1017/S1041610212001081
  • Graff, M.J., Vernooij-Dassen, M.J., Thijssen, M., Dekker, J., Hoefnagels, W.H., & Olderikkert, M.G. (2007). Effects of community occupational therapy on quality of life, mood, and health status in dementia patients and their caregivers: A randomized controlled trial. Journal of Gerontology: Biological and Medical Sciences, 62, 1002–1009. doi:10.1186/1745-6215-15-74
  • Hicks, R., & Tingley, D. (2011). Causal mediation analysis. The Stata Journal, 11, 609–615.
  • Ho, D.E., Imai, K., King, G., & Stuart, E.A. (2007). Matching as nonparametric preprocessing for reducing model dependence in parametric causal inference. Political Analysis, 15, 199–236. doi:10.1093/pan/mpl013
  • Hoe, J., Hancock, G., Livingston, G., Woods, B., Challis, D., & Orrell, M. (2009). Changes in the quality of life of people with dementia living in care homes. Alzheimer Disease and Associated Disorders, 23, 285–290. doi:10.1097/WAD.0b013e318194fc1e
  • Houtjes, W., van Meijel, B., Deeg, D.J., & Beekman, A.T. (2011). Unmet needs of outpatients with late-life depression: A comparison of patient, staff and carer perceptions. Journal of Affective Disorders, 134, 242–248. doi:10.1016/j.jad.2011.05.052
  • Hybels, C.F., Pieper, C.F., & Blazer, D.G. (2009). The complex relationship between depressive symptoms and functional limitations in community dwelling older adults: The impact of subthreshold depression. Psychological Medicine, 39, 1677–1688. doi:10.1017/S0033291709005650
  • Imai, K., Keele, L., & Tingley, D. (2010). A general approach to causal mediation analysis. Psychological Methods, 15, 309–334. doi:10.1037/a0020761
  • Imai, K., Keele, L., Tingley, D., & Yamamoto, T. (2010). Causal mediation analysis using R. In H.D. Vinod (Ed.), Advances in social science research using R (pp. 129–154). New York, NY: Springer.
  • Imai, K., Keele, L., Tingley, D., & Yamamoto, T. (2011). Unpacking the black box of causality learning about causal mechanisms from experimental and observational studies. American Political Science Review, 105, 765–789. doi:10.1017/S0003055411000414
  • Imai, K., Keele, L., & Yamamoto, T. (2013). Experimental designs for identifying causal mechanisms. Journal of the Royal Statistical Society, 176, 5–51. doi:10.1111/j.1467-985X.2012.01032
  • Imbens, G.W. (2003). Sensitivity to exogeneity assumptions in program evaluation. American Economic Review, 93, 126–132. doi:10.1257/000282803321946921
  • Johansson, M.M., Marcusson, J., & Wressle, E. (2015).Cognitive impairment and its consequences in everyday life: Experiences of people with mild cognitive impairment or mild dementia and their relatives. International Psychogeriatrics, 27, 949–958. doi:10.1017/S1041610215000058
  • Keating, N., & Gaudet, N. (2012). Quality of life of persons with dementia. Journal of Nutrition & Health Aging, 16, 454–456. doi:10.1007/s12603-011-0346-4
  • Kiosses, D.N., Ravdin, L.D., Gross, J.J., Raue, P., Kotbi, N., & Alexopoulos, G.S. (2015). Problem adaptation therapy for older adults with major depression and cognitive impairment: A randomized clinical trial. JAMA Psychiatry, 72, 22–30. doi:10.1001/jamapsychiatry.2014.1305
  • Kwok, T., Young, D., Yip, A., & Ho, F. (2013) Effectiveness of day care services for dementia patients and their caregivers. Asian Journal of Gerontology & Geriatrics, 8, 9–15.
  • Lawton, M.P. (1994). Quality of life in Alzheimer disease. Alzheimer Disease and Associated Disorders, 8, 138–150.
  • Lesher, E.L., & Berryhill, J.S. (1994). Validation of the geriatric depression scale – short form among inpatients. Journal of Clinical Psychology, 50, 256–260. doi:10.1002/1097-4679(199403)50:23.0.CO;2-E
  • Leung, P., Orrell, M., & Orgeta, V. (2015). Social support group interventions in people with dementia and mild cognitive impairment: A systematic review of the literature. International Journal of Geriatric Psychiatry, 30, 1–9. doi:10.1002/gps.4166
  • Lin Kiat Yap, P., Yen Ni Goh, J., Henderson, L. M., Min Han, P., Shin Ong, K., & Si Ling Kwek, S. (2008). How do Chinese patients with dementia rate their own quality of life? International Psychogeriatrics, 20, 482–493. doi:10.1017/S1041610207006096
  • Liu, C.P., Leung, D.S., & Chi, I. (2011). Social functioning, polypharmacy and depression in older Chinese primary care patients. Aging & Mental Health, 15, 732–741. doi:10.1080/13607863.2011.562174
  • Livingston, G., Cooper, C., Woods, J., Milne, A., & Katona, A. (2008). Successful ageing in adversity: The LASER-AD longitudinal study. Journal of Neurology, Neurosurgery and Psychiatry, 79, 641–645. doi:10.1136/jnnp.2007.126706
  • Logsdon, R.G., Gibbons, L. E., McCurry, S.M., & Teri, L. (2002). Assessing quality of life in older adults with cognitive impairment. Psychosomatic Medicine, 64, 510–519. doi:10.1097/00006842-200205000-00016
  • López, J., Losada, A., Romero-Moreno, R., Márquez-González, M., & Martínez-Martín, P. (2012). Factors associated with dementia caregivers' preference for institutional care. Neurologia, 27, 83–89. doi:10.1016/j.nrl.2011.04.003
  • Lucas-Carrasco, R., Gómez-Benito, J., Rejas, J., & Brod, M. (2011). The Spanish version of the dementia quality of life questionnaire: A validation study. Aging & Mental Health, 15, 482–489. doi:10.1080/13607863.2010.543658
  • Lumley, T., & Zeieis, A. (2013). Sandwich package. R package version 2.3.0. Vienna: R Foundation for Statistical Computing. Retrieved from http//www.R-project.org/
  • Lynch, K.G., Cary, M., Gallop, R., & Ten Have, T.R. (2008). Causal mediation analyses for randomized trials. Health Services & Outcomes Research Methodology, 8, 57–76. doi:10.1007/s10742-008-0028-9
  • Mahoney, F., & Barthel, D. (1965). Functional evaluation: The Barthel Index. Maryland State Medical Journal, 14, 61–65.
  • Manski, C.F. 2007. Identification for prediction and decision. Cambridge, MA: Harvard University Press.
  • McKhann, G., Drachman, D., Folstein, M., Katzman, R., Price, D., & Stadlan, E.M. (1984). Clinical diagnosis of Alzheimer's disease report of the NINCDS-ADRDA work group under the auspices of Department of Health and Human Services Task Force on Alzheimer's disease. Neurology, 34, 939–944. doi:10.1212/wnl.34.7.939
  • Miranda-Castillo, C., Woods, B., Galboda, K., Oomman, S., Olojugba, C., & Orrell, M. (2010). Unmet needs, quality of life and support networks of people with dementia living at home. Health and Quality of Life Outcomes, 8, 132. doi:10.1186/1477-7525-8-132.
  • Miranda-Castillo, C., Woods, R.T., & Orrell, M. (2010). People with dementia living alone: What are their needs and what kind of support are they receiving? International Psychogeriatrics, 22, 607–617. doi:http://dx.doi.org/10.1017/S104161021000013X
  • Missotten, P., Ylieff, M., Di Notte, D., Paquay, L., De Lepeleire, J., & Fontaine, O. (2007). Quality of life in dementia: A 2-year follow-up study. International Journal of Geriatric Psychiatry, 22, 1201–1207. doi:10.1002/gps.1814
  • Mjørud, M., Kirkevold, M., Røsvik, J., Selbæk, G., & Engedal, K. (2014). Variables associated to quality of life among nursing home patients with dementia. Aging & Mental Health, 18, 1013–1021. doi:10.1080/13607863.2014.903468
  • Monaci, L., & Morris, R.G. (2012). Neuropsychological screening performance and the association with activities of daily living and instrumental activities of daily living in dementia: Baseline and 18- to 24-month follow-up. International Journal of Geriatric Psychiatry, 27, 197–204. doi:10.1002/gps.2709
  • Moniz-Cook, E., Vernooij-Dassen, M., Woods, R., Verhey, F., Chattat, R., De Vugt M., … Interdem group. (2008). A European consensus on outcome measures for psychosocial intervention research in dementia care. Aging & Mental Health, 12, 14–29. doi:10.1080/13607860801919850
  • Moyle, W., Fetherstonhaugh, D., Greben, M., Beattie, E., & AusQoL group. (2015). Influencers on quality of life as reported by people living with dementia in long-term care: A descriptive exploratory approach. BMC Geriatrics, 15, 50. doi:10.1186/s12877-015-0050-z
  • Muthen, B., & Asparouhov, T. (2015). Causal effects in mediation modeling: An introduction with applications to latent variables. Structural Equation Modeling: A Multidisciplinary Journal, 22, 12–23. doi:10.1080/10705511.2014.935843
  • Naglie, G., Hogan, D.B., Krahn, M., Beattie, B.L., Black, S.E., MacKnight, C., & Tomlinson, G. (2011). Predictors of patient self-ratings of quality of life in Alzheimer's disease: Cross-sectional results from the Canadian Alzheimer's Disease Quality of Life (CADQOL) Study. The American Journal of Geriatric Psychiatry, 19, 891–901. doi:10.1097/JGP.0b013e3182006a7f
  • Pearl, J. (2009). Causal inference in statistics: An overview. Statistics Surveys, 3, 96–146. doi:10.1214/09-SS057
  • Pedro-Cuesta, J., Virués-Ortega, J., Vega, S., Seijo-Martínez, M., Saz, P., Rodríguez, F., … del Barrio, J.L. (2009). Prevalence of dementia and major dementia subtypes in Spanish populations: A reanalysis of dementia prevalence surveys, 1990–2008. BMC Neurology, 9, 55. doi:10.1186/1471-2377-9-55.
  • Preston, L., Marshall, A., & Bucks, R.S. (2007). Investigating the ways that older people cope with dementia: A qualitative study. Aging & Mental Health, 11, 131–143. doi:10.1080/13607860600844572
  • Rabins, P.V., & Black, B.S. (2007). Measuring quality of life in dementia purposes, goals, challenges and progress. International Psychogeriatrics, 719, 401–407. doi:10.1017/S1041610207004863
  • Reisberg, B., Ferris, S.H., De Leon, M.J., & Crook, T. (1982). The Global Deterioration Scale for assessment of primary degenerative dementia. American Journal of Psychiatry, 139, 1136–1139. doi:10.1176/ajp.139.9.1136
  • Rickenbach, E.H., Condeelis, K.L., & Haley, W.E. (2015). Daily stressors and emotional reactivity in individuals with mild cognitive impairment and cognitively healthy controls. Psychology & Aging, 30, 420–431. doi:10.1037/a0038973
  • Rivera, J., Bermejo, F., Franco, M., Morales-González, J.M., & Benito-León, J. (2009). Understanding care of people with dementia in Spain: Cohabitation arrangements, rotation and rejection to long term care institution. International Journal of Geriatric Psychiatry, 24, 142–148. doi:10.1002/gps.2081
  • Rizzi, L., Rosset, I., & Roriz-Cruz, M. (2014). Global epidemiology of dementia: Alzheimer's and vascular types. Biomedical Research International. Advance online publication. doi:10.1155/2014/908915
  • Rog, L.A., Park, L.Q., Harvey, D.J., Huang, C.J., Mackin, S., & Farias, S.T. (2014). The independent contributions of cognitive impairment and neuropsychiatric symptoms to everyday function in older adults. Clinical Neuropsychology, 28, 215–236. doi:10.1080/13854046.2013.876101
  • Rubin, D.B. (2005). Causal inference using potential outcomes: Design, modeling, decisions. Journal of the American Statistical Association, 100, 322–331. doi:10.1198/016214504000001880
  • Sainsbury, A., Seebass, G., Bansal, A., & Young, J. (2005). Reliability of the Barthel Index when used with older people. Age and Ageing, 34, 228–232. doi:10.1093/ageing/afi063
  • Schieman, S., & Plickert, G. (2007). Functional limitations and changes in levels of depression among older adults: A multiple-hierarchy stratification perspective. Journal of Gerontology: Social Sciences, 62, S36–S42. doi:10.1093/geronb/62.1.S36
  • Schölzel-Dorenbos, C.J., van der Steen, M.J., Engels, L.K., & Olde Rikkert, M.G. (2007). Assessment of quality of life as outcome in dementia and MCI intervention trials: A systematic review. Alzheimer Disease & Associated Disorders, 21, 172–178. doi:10.1097/WAD.0b013e318047df4c
  • Schwarzbach, M., Luppa, M., Sikorski, C., Fuchs, A., Maier, W., van den Bussche, H., … Riedel-Heller, S.G. (2013). The relationship between social integration and depression in non-demented primary care patients aged 75 years and older. Journal of Affective Disorders, 145, 172–178. doi:10.1016/j.jad.2012.07.025
  • Serrano, J.P., Latorre, J.M., & Gatz, M. (2014). Spain: Promoting the welfare of older adults in the context of population aging. Gerontologist, 54, 733–740. doi:10.1093/geront/gnu010
  • Shah, S., Vanclay, F., & Cooper B. (1989). Improving the sensitivity of the Barthel Index for stroke rehabilitation. Journal of Clinical Epidemiology, 42, 703–709.
  • Sheehan, B.D., Lall, R., Stinton, C., Mitchell, K., Gage, H., Holland, C., … Katz, J. (2012). Patient and proxy measurement of quality of life among general hospital in-patients with dementia. Aging & Mental Health, 16, 603–607. doi:10.1080/13607863.2011.653955
  • Siedlecki, K.L., Tatarina, O., Sanders, L., Albert, M., Blacker, D., Dubois, B., … Stern, Y. (2009). Comparison of patient and caregiver reports of patient activity participation and its relationship to mental health in patients with Alzheimer's disease. The Journals of Gerontology Series B: Psychological Sciences & Social Sciences, 64B, 687–695. doi:10.1093/geronb/gbp071
  • Suh, G.H., Ju, Y.S., Yeon, B.K., & Shah, A.A. (2004). Longitudinal study of Alzheimer's disease: Rates of cognitive and functional decline. International Journal of Geriatric Psychiatry, 19, 817–824. doi:10.1002/gps.1168
  • Tatsumi, H., Nakaaki, S., Torii, K., Shinagawa, Y., Watanabe, N., Murata, Y., … Furukawa, T.A. (2009). Neuropsychiatric symptoms predict change in quality of life of Alzheimer disease patients: A two-year follow-up study. Psychiatry & Clinical Neuroscience, 63, 374–384. doi:10.1111/j.1440-1819.2009.01955.x
  • Tingley, D., Yamamoto, T., Hirose, K., Keele, L., & Imai, K. (2014). Mediation R package for causal mediation analysis. Journal of Statistical Software, 59, 1–40.
  • Weiss, E.M., Kohler, C.G., Vonbank, J., Stadelmann, E., Kemmler, G., Hinterhuber, H., … Marksteiner, J. (2008). Impairment in emotion recognition abilities in patients with mild cognitive impairment, early and moderate Alzheimer disease compared with healthy comparison subjects. American Journal of Geriatrics Psychiatry, 6, 974–980. doi:10.1097/JGP.0b013e318186bd53
  • Wilks, S.E., & Croom, B. (2008). Perceived stress and resilience in Alzheimer's disease caregivers: Testing moderation and mediation models of social support. Aging & Mental Health, 12, 357–365. doi:10.1080/13607860801933323
  • Woods, R.T., Nelis, S.M., Martyr, A., Roberts, J., Whitaker, C.J., & Markova, I. (2014). What contributes to a good quality of life in early dementia? Awareness and the QoL-AD, a cross-sectional study. Health & Quality of Life Outcomes, 11. doi:10.1186/1477-7525-12-94
  • World Health Organization Quality of Life. (1995). The World Health Organization Quality of Life assessment (WHOQOL): Position paper from the World Health Organization. Social Science & Medicine, 41, 1403–1409. doi:10.1016/0277-9536(95)00112-K
  • Yesavage, J.A., Brink, T.L., Rose, T.L., & Lum, O. (1983). Development and validation of a geriatric depression scale a preliminary report. Journal of Psychiatric Research, 17, 37–49. doi:10.1016/0022-3956(82)90033-4
  • Zahodne, L.B., & Tremont G. (2013). Unique effects of apathy and depression signs on cognition and function in amnestic mild cognitive impairment. International Journal of Geriatric Psychiatry, 28, 50–56. doi:10.1002/gps.3789
  • Zhang, S., Edwards, H., Yates, P., Li, C., & Guo, Q. (2014). Self-efficacy partially mediates between social support and health-related quality of life in family caregivers for dementia patients in Shanghai. Dementia & Geriatric Cognitive Disorders, 37, 34–44. doi:10.1159/000351865

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.