CLEVER: Cognitive Level Enhancement Through Vision Exams and Refraction
Study Details
Study Description
Brief Summary
The investigators aim to conduct a mixed-method study in which a randomised controlled trial (RCT) and a descriptive qualitative study will be conducted. The RCT aims to determine whether free near and distance glasses provided to residents in Hyderabad, India, aged ≥ 60 years, with under- or un- corrected refractive error and normal baseline hearing and cognition (HMSE > 18), can improve quality of life, reduce falls, reduce depression, improve social interaction and physical activity cost-effectively over 36 months. The primary qualitative research aim is to a) contextualize the RCT with information on the milieu and culture in which the trial will be conducted; b) provide data on the lived experiences of older adults with reduced vision in the study area, and c) conduct a process evaluation of the trial.
The primary outcome measure is the three-year change in cognition measured by LASI- DAD (Longitudinal Aging Study in India(LASI)- Diagnostic Assessment of Dementia(DAD) global cognitive score.
Secondary Outcome Measures:
Domain-specific cognitive function (orientation, executive function, language/fluency, memory), quality of life (WHOQOL BREF), self-reported visual functioning (INDVFQ), falls, mobility, depression (PHQ9), glasses compliance, cost-effectiveness (total intervention cost per additional quality-adjusted life years(QALY) gained in the intervention group), social interaction/isolation (Social Networking Index, SNI), self-reported physical activity (GPAQ). An additional secondary outcome will be LASI-DAD global cognitive score analysed by excluding any tests determined pre-hoc to depend on visual acuity.
Condition or Disease | Intervention/Treatment | Phase |
---|---|---|
|
N/A |
Detailed Description
The number of people living with dementia globally will rise from 50 million in 2017 to 131.5 million by 2050. The majority reside in low and middle-income countries (LMICs), where a 223% increase in the burden of dementia is expected from 2015 to 2050. The household cost of caring for demented relatives in India was £2.48 billion in 2013, where total expenses for dementia care will soon consume 0.5% of Gross Domestic Product (GDP). Despite the rapidly-growing burden of dementia in India, only 1 in 10 affected are diagnosed or treated. Proven preventive strategies are desperately needed to close the gap, and could reduce incidence by an estimated 41%, especially early, at the stage of mild cognitive impairment, which itself increases risk of dementia by 23-fold. Existing interventions have predominantly been evaluated in high-income countries (HIC), despite the acknowledged need for prevention in low resource settings. India's national dementia strategy, documented in the Alzheimer's and Related Society of India (ARDSI) Report (2018) and Dementia in India (2020), echo the WHO Dementia Global Action Plan (2017) in prioritising evidence-based approaches to reduce risk.
The elderly, at greatest risk for cognitive disorders, also have the highest prevalence of vision impairment, which affects 2.2 billion persons globally. Growing longitudinal evidence links vision impairment and risk of cognitive decline, with population studies in the United States reporting a 55% increased 9-year risk of new cognitive impairment among visually impaired persons. Longitudinal studies elsewhere in the United States, France, Singapore and China report similar results. While vision impairment is a strong predictor of future cognitive performance, cognition is relatively weakly linked to future visual decline. Both distance impairment and impairment of near vision, a nearly universal part of aging without refractive correction, have been implicated. Observational studies also suggest vision care slows rates of cognitive decline by up to 50%. The association between vision loss and cognitive decline and dementia, while consistent and strong, is not well understood, and various causal pathways have been posited. These include common neurodegenerative or micro vascular aetiology, increased cognitive load, and limited social contact and physical activity due to poor vision, each independently shown to elevate risk of dementia. Studies investigating the role of vision correction in slowing cognitive decline will have a significant impact in developing strategies to reduce the burden of dementia.
Design: single centre, open label, two-arm, parallel group, stratified, interventional randomised trial with a qualitative component Rationale: Despite considerable longitudinal observational evidence, there have been no randomised trials to investigate whether providing near and distance glasses can slow cognitive decline in the elderly. Proof of a causative association between vision correction and the slowing of cognitive decline is needed to potentiate investment in inexpensive vision care for prevention. This requires randomised trials, and none have yet been done.
Study Plan:
Eligibility assessments conducted for 1300 participants. After providing the consent and meeting the eligibility criteria, 760 participants randomised to intervention and control groups.
Annual follow-ups for 3 years for both groups. Lost to follow ups documented with reason for both groups. Missed data for both groups analysed as intention to treat (ITT) and will be excluded from analysis with reasons documented.
Primary outcomes: Three-year change in cognition measured by LASI-DAD global cognitive score.
Secondary Outcome Measures: Domain-specific cognitive function (orientation, executive function, language/fluency, memory), quality of life (WHOQOL BREF), self-reported visual functioning (INDVFQ), falls, mobility, depression (PHQ9), glasses compliance, cost-effectiveness (total intervention cost per additional QALY gained in the intervention group), social interaction/isolation (Social Networking Index, SNI), self-reported physical activity (GPAQ). An additional secondary outcome will be LASI-DAD global cognitive score analysed by excluding any tests determined pre-hoc to depend on visual acuity.
Hindi Mental State Examination, Medical history and comorbidity questionnaire, Hearing Questionnaire, Client Services Receipt Inventory.
Statistical methods: The primary analysis will use a significance level of <0.05 and will compare the change in LASI-DAD global cognitive score (primary outcome, with sensitivity analysis including and excluding vision-dependent tests) between groups using a 2-sample t-test. Both the raw comparison, and the comparison adjusting for potential determinants of change in cognitive status, such as baseline cognitive score, age, sex and education (further covariates will be detailed in the SAP) using general linear models. Similar methods will be used for other time-points and secondary outcomes that are continuous data.
Justification for sample size: Imputing three-year un-intervened decline in the outcome variable (LASI-DAD global score from cross-sectional, age-stratified data17, at 29% effect size (from the ACHIEVE study), 502 participants give 90% power at p = 0.05 (two-tailed) based on a two-sample test. With annual follow-up loss of 13% based on estimation from previous studies done in India, 760 total participants are needed across the two study groups. With 60% prevalence of uncorrected distance and/or near refractive error, the total number of people needing to be screened is estimated at approximately 1300.
Study Design
Arms and Interventions
Arm | Intervention/Treatment |
---|---|
Experimental: Free near and distance glasses All participants randomised to the intervention group will be provided with free near and/or distance spectacles based on the results of refraction. The participants will be asked to choose from an assortment of 20 frames. Participants will be asked to report to the project coordinator in case of any issue with spectacles or if spectacles are lost or broken. Replacement glasses will be provided in case of broken or lost spectacles whenever required. Participants will undergo annual eye exams and refraction, and change of glasses will be prescribed as needed. |
Device: Free near and Distance Vision glasses
Intervention Description: All participants randomised to the intervention group will be provided with free near and/or distance spectacles based on the results of refraction.
|
No Intervention: Control-No treatment All participants randomised to the control group will receive a prescription for spectacles and given free near and/or distance glasses as needed at study close out. |
Outcome Measures
Primary Outcome Measures
- Change in cognitive score [Time point(s) of primary interest: 36 months collected at 12, 24 and 36 months]
The metric or method of measurement to be used: LASI-DAD global cognitive score. The best possible score is 360 and the worst possible score is 0.
Secondary Outcome Measures
- 26-Item Quality of Life [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Quality of Life using WHO BREF questionnaire. Higher scores (for 4 domains) indicate higher quality of life and vice versa (it is a continuum)
- Cost effectiveness [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Cost-effectiveness using Client Service Receipt Inventory
- Social interaction/isolation [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Social Networking Index. The best possible score is 12 and the worst possible score is 0
- Self-reported physical activity. [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Global Physical Activity Questionnaire Self-reported physical activity: Global Physical Activity Questionnaire (GPAQ).
- Falls [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Quick Screen for falls Risk. The worst possible score is 7% and the best possible score is 49%
- Depression [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Patient Health Questionnaire, PHQ9. Worst score is 0 and best possible score is 27
- Glasses compliance [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Use of glasses during follow-up visits. The best possible score is 1 and the worst possible score is 0
- Visual Function [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Indian VFQ. The measure will be in logits (using Rasch-scaled interval scores) and it is a continuum with positive person scores indicating lower visual functioning and negative scores indicating better visual functioning.
- Domain-specific cognitive function [Time point(s) of primary interest: 36 months collected every 12 months - ie at 12, 24 and 36 months]
The metric or method of measurement to be used: Hindi Mental State Examination. The best possible score is 31 and the worst possible score is 0.
Eligibility Criteria
Criteria
Inclusion Criteria
-
Community dwelling
-
Residency
- Participants must plan to reside in the local area for the study duration
-
Presenting vision in the better eye due to uncorrected refractive error
-
Impaired distance vision less than 6/12
-
Near vision less than N8 at 40 cm
-
Presenting vision in the better eye due to under-corrected refractive error
-
Impaired distance vision less than 6/12
-
Near vision less than N8 at 40 cm
-
Willingness
-
to participate
-
to be randomized
-
to adhere to the protocol
Exclusion criteria
- Impaired baseline cognition
- HMSE score less than or equal to 18
-
Non-refractive causes of vision impairment
-
Severely impaired mobility
-
immobile
-
bedridden
-
wheelchair
-
using walker
-
Severe medical illness likely to limit the life span
-
Cancer
-
Heart disease
-
Stroke
-
HIV or AIDS
-
Chronic lung disease
-
Kidney disease
-
Hearing loss assessment
-
self-reported hearing impairment
-
inability to hear
-
inability to repeat short phrases in local languages
Contacts and Locations
Locations
Site | City | State | Country | Postal Code | |
---|---|---|---|---|---|
1 | L V Prasad Eye Institute | Hyderabad | Telangana | India | 500086 |
Sponsors and Collaborators
- Queen's University, Belfast
- L.V. Prasad Eye Institute
- National Institute of Mental Health and Neuro Sciences, India
- The George Institute
- Johns Hopkins University
- University of Michigan
- Clearly
- Belfast Health and Social Care Trust
Investigators
- Principal Investigator: Nathan G Congdon, MD, MPH, Queen's University, Belfast
- Principal Investigator: Rohit C Khanna, MPH, L.V. Prasad Eye Institute
- Principal Investigator: Suvarna Alladi, DM, National Institute of Mental Health and Neuro Sciences, India
Study Documents (Full-Text)
None provided.More Information
Publications
- Akl EA, Treweek S, Foy R, Francis J, Oxman AD; ReBEQI group. NorthStar, a support tool for the design and evaluation of quality improvement interventions in healthcare. Implement Sci. 2007 Jun 26;2:19.
- Angrisani M, Jain U, Lee J. Sex Differences in Cognitive Health Among Older Adults in India. J Am Geriatr Soc. 2020 Aug;68 Suppl 3:S20-S28. doi: 10.1111/jgs.16732.
- Arksey H, O'Malley L. Scoping studies: towards a methodological framework. International Journal of Social Research Methodology 2005;8:19-32
- Aromataris E MZE. JBI Manual for Evidence Synthesis. JBI: Adelaide, Australia (2020). 2020
- Aung MN, Moolphate S, Aung TN, Katonyoo C, Khamchai S, Wannakrairot P. The social network index and its relation to later-life depression among the elderly aged ≥80 years in Northern Thailand. Clin Interv Aging. 2016 Aug 8;11:1067-74. doi: 10.2147/CIA.S108974. eCollection 2016.
- Bull FC, Maslin TS, Armstrong T. Global physical activity questionnaire (GPAQ): nine country reliability and validity study. J Phys Act Health. 2009 Nov;6(6):790-804.
- Craig P, Dieppe P, Macintyre S, Michie S, Nazareth I, Petticrew M; Medical Research Council Guidance. Developing and evaluating complex interventions: the new Medical Research Council guidance. BMJ. 2008 Sep 29;337:a1655. doi: 10.1136/bmj.a1655.
- Development of the World Health Organization WHOQOL-BREF quality of life assessment. The WHOQOL Group. Psychol Med. 1998 May;28(3):551-8.
- Erlingsson C, Brysiewicz P. A hands-on guide to doing content analysis. Afr J Emerg Med. 2017 Sep;7(3):93-99. doi: 10.1016/j.afjem.2017.08.001. Epub 2017 Aug 21.
- Folstein MF, Folstein SE, McHugh PR. "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975 Nov;12(3):189-98.
- Forero R, Nahidi S, De Costa J, Mohsin M, Fitzgerald G, Gibson N, McCarthy S, Aboagye-Sarfo P. Application of four-dimension criteria to assess rigour of qualitative research in emergency medicine. BMC Health Serv Res. 2018 Feb 17;18(1):120. doi: 10.1186/s12913-018-2915-2.
- Gambhir IS, Khurana V, Kishore D, Sinha AK, Mohapatra SC. A clinico-epidemiological study of cognitive function status of community-dwelling elderly. Indian J Psychiatry. 2014 Oct;56(4):365-70. doi: 10.4103/0019-5545.146531.
- Gothwal VK, Bagga DK, Sumalini R. Rasch analysis of the Indian vision function questionnaire. Br J Ophthalmol. 2012 May;96(5):619-23. doi: 10.1136/bjophthalmol-2011-300092. Epub 2012 Feb 2.
- Grant A, Treweek S, Dreischulte T, Foy R, Guthrie B. Process evaluations for cluster-randomised trials of complex interventions: a proposed framework for design and reporting. Trials. 2013 Jan 12;14:15. doi: 10.1186/1745-6215-14-15.
- Guerrero-Castañeda RF, Menezes TMO, Ojeda-Vargas MG. Characteristics of the phenomenological interview in nursing research. Rev Gaucha Enferm. 2017 Jul 6;38(2):e67458. doi: 10.1590/1983-1447.2017.02.67458. Spanish, English.
- Gupta SK, Viswanath K, Thulasiraj RD, Murthy GV, Lamping DL, Smith SC, Donoghue M, Fletcher AE. The development of the Indian vision function questionnaire: field testing and psychometric evaluation. Br J Ophthalmol. 2005 May;89(5):621-7.
- Hadi MA, José Closs S. Ensuring rigour and trustworthiness of qualitative research in clinical pharmacy. Int J Clin Pharm. 2016 Jun;38(3):641-6. doi: 10.1007/s11096-015-0237-6. Epub 2015 Dec 14. Review.
- Hankins M, Smith H. GPAQ. Br J Gen Pract. 2007 Dec;57(545):994. doi: 10.3399/096016407782604956.
- Hemming K, Taljaard M, Grimshaw J. Introducing the new CONSORT extension for stepped-wedge cluster randomised trials. Trials. 2019 Jan 18;20(1):68. doi: 10.1186/s13063-018-3116-3.
- Herdman M, Gudex C, Lloyd A, Janssen M, Kind P, Parkin D, Bonsel G, Badia X. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Qual Life Res. 2011 Dec;20(10):1727-36. doi: 10.1007/s11136-011-9903-x. Epub 2011 Apr 9.
- Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001 Sep;16(9):606-13.
- Lee ATC, Richards M, Chan WC, Chiu HFK, Lee RSY, Lam LCW. Higher Dementia Incidence in Older Adults with Poor Visual Acuity. J Gerontol A Biol Sci Med Sci. 2020 Oct 15;75(11):2162-2168. doi: 10.1093/gerona/glaa036.
- Lee J, Banerjee J, Khobragade PY, Angrisani M, Dey AB. LASI-DAD study: a protocol for a prospective cohort study of late-life cognition and dementia in India. BMJ Open. 2019 Jul 31;9(7):e030300. doi: 10.1136/bmjopen-2019-030300.
- Lee J, Khobragade PY, Banerjee J, Chien S, Angrisani M, Perianayagam A, Bloom DE, Dey AB. Design and Methodology of the Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD). J Am Geriatr Soc. 2020 Aug;68 Suppl 3:S5-S10. doi: 10.1111/jgs.16737.
- Lim ZW, Chee ML, Soh ZD, Cheung N, Dai W, Sahil T, Tao Y, Majithia S, Sabanayagam C, Chen CL, Wong TY, Cheng CY, Tham YC. Association Between Visual Impairment and Decline in Cognitive Function in a Multiethnic Asian Population. JAMA Netw Open. 2020 Apr 1;3(4):e203560. doi: 10.1001/jamanetworkopen.2020.3560. Erratum in: JAMA Netw Open. 2020 May 1;3(5):e209437.
- Maharani A, Dawes P, Nazroo J, Tampubolon G, Pendleton N; SENSE-Cog WP1 group. Cataract surgery and age-related cognitive decline: A 13-year follow-up of the English Longitudinal Study of Ageing. PLoS One. 2018 Oct 11;13(10):e0204833. doi: 10.1371/journal.pone.0204833. eCollection 2018. Erratum in: PLoS One. 2018 Nov 20;13(11):e0208045.
- Marmamula S, Challa R, Khanna RC, Kunkunu E, Rao GN. Population-based Assessment of Vision Impairment in the Elderly Population in Telangana State in India - Policy Implications for Eye Health Programmes. Ophthalmic Epidemiol. 2021 Apr;28(2):144-151. doi: 10.1080/09286586.2020.1797122. Epub 2020 Aug 4.
- Marmamula S, Challa R, Yellapragada S, Mohd J, Khanna RC. Temporal trends in the prevalence of spectacle use and spectacle coverage in India. Clin Exp Optom. 2020 Sep;103(5):693-698. doi: 10.1111/cxo.13025. Epub 2019 Dec 11.
- Marmamula S, Keeffe J, Challa R, Mohd J, Khanna RC. Near-vision impairment and effective near-vision spectacle coverage in two districts in Telangana, India: a population-based cross-sectional study. BMJ Open. 2021 Apr 5;11(4):e047131. doi: 10.1136/bmjopen-2020-047131.
- Marmamula S, Khanna RC, Kunkunu E, Rao GN. Population-based assessment of prevalence and causes of visual impairment in the state of Telangana, India: a cross-sectional study using the Rapid Assessment of Visual Impairment (RAVI) methodology. BMJ Open. 2016 Dec 15;6(12):e012617. doi: 10.1136/bmjopen-2016-012617.
- Marmamula S, Khanna RC, Kunuku E, Rao GN. Near visual impairment and spectacle coverage in Telangana, India. Clin Exp Ophthalmol. 2017 Aug;45(6):568-574. doi: 10.1111/ceo.12943. Epub 2017 Apr 5.
- Moore GF, Audrey S, Barker M, Bond L, Bonell C, Hardeman W, Moore L, O'Cathain A, Tinati T, Wight D, Baird J. Process evaluation of complex interventions: Medical Research Council guidance. BMJ. 2015 Mar 19;350:h1258. doi: 10.1136/bmj.h1258.
- Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018 Nov 19;18(1):143. doi: 10.1186/s12874-018-0611-x.
- Naël V, Pérès K, Dartigues JF, Letenneur L, Amieva H, Arleo A, Scherlen AC, Tzourio C, Berr C, Carrière I, Delcourt C, Helmer C; Sense-Cog consortium. Vision loss and 12-year risk of dementia in older adults: the 3C cohort study. Eur J Epidemiol. 2019 Feb;34(2):141-152. doi: 10.1007/s10654-018-00478-y. Epub 2019 Jan 4.
- Pawson R, Tilley N. Realistic evaluation: Sage; 1997 June 23.
- Peat G, Rodriguez A, Smith J. Interpretive phenomenological analysis applied to healthcare research. Evid Based Nurs. 2019 Jan;22(1):7-9. doi: 10.1136/ebnurs-2018-103017. Epub 2018 Dec 1.
- Rafnsson SB, Orrell M, d'Orsi E, Hogervorst E, Steptoe A. Loneliness, Social Integration, and Incident Dementia Over 6 Years: Prospective Findings From the English Longitudinal Study of Ageing. J Gerontol B Psychol Sci Soc Sci. 2020 Jan 1;75(1):114-124. doi: 10.1093/geronb/gbx087.
- Rogers EM. Diffusion of innovations. New York: Free Press; 2003
- Salcher-Konrad M, Naci H, McDaid D, Alladi S, Oliveira D, Fry A, Hussein S, Knapp M, Musyimi CW, Ndetei DM, Lopez-Ortega M, Comas-Herrera A. Effectiveness of interventions for dementia in low- and middle-income countries: protocol for a systematic review, pairwise and network meta-analysis. BMJ Open. 2019 Jun 19;9(6):e027851. doi: 10.1136/bmjopen-2018-027851.
- Sandelowski M. Whatever happened to qualitative description? Res Nurs Health. 2000 Aug;23(4):334-40. Review.
- Saxena S, Orley J; WHOQOL Group. Quality of life assessment: The world health organization perspective. Eur Psychiatry. 1997;12 Suppl 3:263s-6s. doi: 10.1016/S0924-9338(97)89095-5.
- Shenton A. Strategies for Ensuring Trustworthiness in Qualitative Research Projects. Education for Information 2004;22:63-75
- Stephenson, Judith M., John Imrie, and C. Bonell. Effective sexual health interventions: issues in experimental evaluation. Oxford University Press, 2003
- Swenor BK, Wang J, Varadaraj V, Rosano C, Yaffe K, Albert M, Simonsick EM. Vision Impairment and Cognitive Outcomes in Older Adults: The Health ABC Study. J Gerontol A Biol Sci Med Sci. 2019 Aug 16;74(9):1454-1460. doi: 10.1093/gerona/gly244. Erratum in: J Gerontol A Biol Sci Med Sci. 2019 Jan 14;:.
- Tan ZS, Spartano NL, Beiser AS, DeCarli C, Auerbach SH, Vasan RS, Seshadri S. Physical Activity, Brain Volume, and Dementia Risk: The Framingham Study. J Gerontol A Biol Sci Med Sci. 2017 Jun 1;72(6):789-795. doi: 10.1093/gerona/glw130.
- Tiedemann A, Lord SR, Sherrington C. The development and validation of a brief performance-based fall risk assessment tool for use in primary care. J Gerontol A Biol Sci Med Sci. 2010 Aug;65(8):896-903. doi: 10.1093/gerona/glq067. Epub 2010 Jun 3.
- Tong A, Sainsbury P, Craig J. Consolidated criteria for reporting qualitative research (COREQ): a 32-item checklist for interviews and focus groups. Int J Qual Health Care. 2007 Dec;19(6):349-57. Epub 2007 Sep 14.
- Tran EM, Stefanick ML, Henderson VW, Rapp SR, Chen JC, Armstrong NM, Espeland MA, Gower EW, Shadyab AH, Li W, Stone KL, Pershing S. Association of Visual Impairment With Risk of Incident Dementia in a Women's Health Initiative Population. JAMA Ophthalmol. 2020 Jun 1;138(6):624-633. doi: 10.1001/jamaophthalmol.2020.0959.
- Tsolaki M, Iakovidou V, Navrozidou H, Aminta M, Pantazi T, Kazis A. Hindi Mental State Examination (HMSE) as a screening test for illiterate demented patients. Int J Geriatr Psychiatry. 2000 Jul;15(7):662-4.
- Ustün TB, Chatterji S, Kostanjsek N, Rehm J, Kennedy C, Epping-Jordan J, Saxena S, von Korff M, Pull C; WHO/NIH Joint Project. Developing the World Health Organization Disability Assessment Schedule 2.0. Bull World Health Organ. 2010 Nov 1;88(11):815-23. doi: 10.2471/BLT.09.067231. Epub 2010 May 20.
- Walker R, Paddick SM. Dementia prevention in low-income and middle-income countries: a cautious step forward. Lancet Glob Health. 2019 May;7(5):e538-e539. doi: 10.1016/S2214-109X(19)30169-X.
- Westhorp G. Realist impact evaluation: an introduction. London: Overseas Development Institute. 2014 Sep 25:1-
- Zheng DD, Swenor BK, Christ SL, West SK, Lam BL, Lee DJ. Longitudinal Associations Between Visual Impairment and Cognitive Functioning: The Salisbury Eye Evaluation Study. JAMA Ophthalmol. 2018 Sep 1;136(9):989-995. doi: 10.1001/jamaophthalmol.2018.2493.
- ENGINE-CLEVER-TP,V4.0 26/05/22