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COVID-19 pandemic partnership between medical students and isolated elders improves student understanding of older adults’ lived experience
BMC Geriatrics volume 22, Article number: 636 (2022)
Evidence supports loneliness and social isolation as a strong risk factor for poor mental and physical health outcomes for older adults. The COVID-19 pandemic necessitated older adults isolate themselves for a prolonged duration. The Faculty of Medicine at the University of Toronto established the Student-Senior Isolation Prevention Partnership (SSIPP), a volunteer program involving telephone calls between medical students and older adults.
A mixed methods pre-post study design included collecting quantitative data from older adults using the UCLA Loneliness Scale and the Warwick-Edinburgh Mental Well-being Scale. The study included 29 medical students and 47 older adults. The medical students filled out a questionnaire on self-perceived knowledge of social isolation, perception of seniors, attitudes towards seniors, and likelihood to engage in specialties focusing on older adults. Interviews were conducted with both the older adults and the medical students to understand each groups’ experiences and perspectives with taking part in the SSIPP program.
Participation in the program resulted in significant changes for medical students in areas such as increasing their likelihood to engage in care for older adults (p < .001), improving their knowledge of social isolation for seniors (p < .001), and the value of addressing social isolation in older adults (p < .001). The interviews conducted with the medical students support these findings and provide insight into contributing factors. Loneliness and mental well-being scales did not show significant changes for older adults however, our interviews revealed they considered the program to be valuable.
Our results showed that after the communication outreach program, medical students’ perceptions were positively influenced towards older adults and they were more likely to pursue a career concentrated on older adults. The qualitative analysis revealed older adults valued the program. Timing and consistency of calls were factors identified by this group as having practical importance.
Loneliness and social isolation in older adults is a growing public health concern. Over 40% of adults aged 60 or older report feeling lonely, while close to one-quarter of adults over 65 are considered to be socially isolated . Loneliness is the “feeling of being alone, regardless of the amount of social contact”, and social isolation describes a lack of social connections . There is strong evidence that older adults who are lonely or socially isolated have increased risks related to their health . Loneliness is associated with increased risk of death, hospitalization, and emergency department visits for older adults with heart failure . Social isolation is linked to an increased risk of premature mortality [3,4,5,6] and developing dementia . This growing concern is coupled with research that suggests ageism amongst physicians-in-training is an issue that may impact social empathy and contribute to a lack of understanding older adults’ care needs [7,8,9]. To address this, the University of Toronto Faculty of Medicine established the Student-Senior Isolation Prevention Partnership (SSIPP), a volunteer program involving visits and calls between 170 medical students and over 300 older adults (www.ssipp.info) . Programs linking seniors with medical students exist elsewhere with a common theme of providing an opportunity for medical students to develop an understanding of care while also providing emotional support to isolated older adults [11,12,13,14]. Office and colleagues  surveyed health science students who volunteered to make one phone call to an older adult living in long-term care facilities in the community who were at risk of isolation. Most students felt the calls were well-received by the participants and that making the phone call was positive. The older adults were appreciative of getting the phone call and of the volunteers’ time. Similarly, van Dyck and colleagues  reported on a telephone outreach program where medical students telephoned nursing home residents on a weekly basis. Both the volunteer students and the recreation directors, reporting on behalf of the residents at the nursing homes, provided positive reports about the program. Although methods for how data was collected for the study were not described, it was indicated that future work would involve collecting qualitative data from the student volunteers to report on the personal and professional impact of the program .
Governmental lockdowns during the COVID-19 pandemic increased the potential for isolation risk and focused attention on communication outreach programs. Given the increased interest in programs that connect students with older adults to address issues such as loneliness and social isolation, a rigorous evaluation is necessary to provide a better understanding of their impact. We planned a mixed methods study examining medical students and older adults who were matched to take part in regular phone or video calls. The purpose of the study is to determine the effect of regular medical student led outreach phone or video calls to older adults in the context of social isolation imposed by the COVID-19 pandemic.
We used a concurrent triangulation mixed methods study design. The goal of this design is “to obtain different but complementary data on the same topic”  in order to understand a research issue. Collecting both quantitative (data that can be counted or measured) and qualitative data (descriptive or conceptual findings) identify the different types of data obtained. These are complementary as the information obtained provides a more refined and complete understanding of the topic . Through the SSIPP program, medical students were paired with an older adult to engage in regular phone calls for a period of 12 weeks from May to August 2020. The students were instructed to allow older adults to speak on whatever they liked, and to focus on providing support through empathic listening. The planning and coordination of the calls such as timing (e.g., time of day, day of week, number of calls per week) or method of communication (e.g., video call, phone call) was left to the student and older adult to coordinate so that it would be agreeable and convenient to both parties. Calls were intended to be about 15–30 min in length. The UCLA Loneliness Scale  and the Warwick-Edinburgh Mental Well-being Scale  were administered pre- and post-intervention. As well, the Lubben Social Network Scale  was used prior to starting the program. The medical students were surveyed on knowledge of social isolation and attitudes towards older adults. Interviews were conducted with both medical students and older adults to offer a richer understanding of the impact and effects of this type of program. Medical students and older adults were recruited independently within the SSIPP program for our study and we made no attempt to recruit matched pairs, (i.e., collect data from both an older adult and the medical student who were put together). As a result, the number of participants for each group is not the same. It is also possible that a medical student may have been connected with more than one older adult.
Older adults were identified by physicians from the Toronto Western Hospital Family Health Team. The Toronto Western Hospital Family Health Team is part of Toronto Western Hospital (twfht.ca), a University of Toronto teaching hospital within the University Health Network, and is an interdisciplinary primary health care practice that provides comprehensive family health care services to a catchment area in the city of Toronto, Canada. Participants were eligible if they were aged 70 years or older, English-speaking, and able to provide consent. Older adults were either emailed or mailed a consent form after agreeing to take part in the study and were contacted at a later date to obtain verbal consent over the phone. We focused on seniors aged 70 years or older as this group is identified as most vulnerable .
The Student-Senior Isolation Prevention Partnership (SSIPP) program hosts a database listing of undergraduate medical students at the University of Toronto who are currently volunteering for the program. Emails were sent to student volunteers inviting them to take part in the study. After replying to the email, informed consent was obtained from the medical student and they were then matched with an older adult. The medical students contacted the older adult they had been matched with, and made arrangements for regular telephone calls.
Older adult questionnaire and validated scales
After obtaining informed consent, the older adults were asked to fill out a questionnaire that collected demographic information (Additional file 1) as well as three validated scales. The Lubben Social Network Scale (Additional file 1) is a validated six-point scale used to assess social isolation in older adults by measuring perceived social support received by family and friends . This was used pre-intervention to understand the extent of each person’s isolation. We measured loneliness with the UCLA Loneliness Scale  that consists of 20 items (Additional file 2). Responses are provided on a 4-point Likert scale from ‘often’ to ‘never’. The UCLA Loneliness Scale is a validated scale designed to measure subjective feelings of loneliness as well as feelings of social isolation . Finally, the Warwick-Edinburgh Mental Well-being Scale  (Additional file 2), a 14-item scale rated on a 5-point scale ranging from ‘none of the time’ to ‘all of the time’, was filled out prior to receiving phone calls from the medical students, as well as post-intervention. The Warwick-Edinburgh Mental Well-being Scale is a “measure of mental well-being focusing entirely on positive aspects of mental health” .
Medical student questionnaires
Prior to placing phone calls to the older adults, the medical students filled out a demographic questionnaire (Additional file 3). As well, they completed a 5-item questionnaire on knowledge of social isolation, perception of seniors, attitudes towards seniors, and likelihood to engage in specialties focusing on older adults that was developed based on the Semantic Differential Technique (Additional file 4)  and was administered at the 12-week point in a retrospective post-then-pre method . Each item was rated on a 5-point scale from 1 (weak) to 5 (strong).
An interview guide was developed for the older adults (Additional file 5) and the medical students (Additional file 6) that asked participants about their experience and perspectives of taking part in the communication outreach program. Interviews were conducted by a member of the study team for both medical students and older adults between June 2020 and August 2020 post-intervention.
Data was collected by telephone for all questionnaires and interviews for both older adults and medical students. Analysis was conducted on the medical student’s questionnaire data with descriptive statistics and a paired t-test (two-tailed) was used to analyze the difference between baseline and post-intervention measures. A p-value of < 0.05 was considered statistically significant. Participants with missing scores were excluded from the statistical analysis. Interview recordings were transcribed verbatim by a transcriptionist. For both the medical students and the older adult transcripts, two investigators (GM, LP, NC) independently generated codes by reading through all transcripts, reflecting on the interview guide, and then independently coding an initial transcript. A meeting was held to compare codes, discuss commonalities, and harmonize inconsistencies. The codes were refined through consensus and included collapsing and adding codes to more accurately represent the data until a final set of codes was generated. After this, two transcripts were coded independently as a set by two researchers and a meeting was held afterwards in order to review coding, resolve discrepancies, and refine the set of codes. Once coding was completed, data was reviewed to create themes and sub-themes within the codes. Microsoft Excel (Microsoft Corp., USA) was used to organize data by codes, and arrange by themes and sub-themes. Lincoln and Guba’s  framework was used to enhance the rigour and quality of the study. Thematic saturation was determined using the method validated by Guest and colleagues  (Additional file 7). Quotes from focus group participants are provided for transparency that offer support for themes and allow readers to judge whether the findings reflect the perceptions of participants. An audit trail of coding and theme development was generated by documenting procedures; this process of triangulation ensured that findings arose from consensus amongst the investigators. The study was approved by the University Health Network Research Ethics Board.
Older adult questionnaire and validated scales
A total of 47 participants completed the study (Table 1) and seven participants were lost to follow up. No significant difference pre- and post-intervention was found for both the UCLA Loneliness Scale and the Warwick-Edinburgh Mental Well-being Scale (Table 2). Upon analyzing the older adult sub-group who scored moderately or high risk on the UCLA Loneliness Scale in the pre-intervention questionnaire (total of 11 participants), There is an improvement in scores, from pre-intervention (mean 58.64, SD 8.23) and post-intervention (mean 53.91, SD 3.37); t10 = 2.13, p = 0.06. While it did not reach statistical significance in our sample, there may be a trend toward a true effect given the p-value of 0.06, just above the threshold of 0.05. Scores for both scales pre- and post-intervention are reported in Additional file 9 and indicate that prior to taking part in the program, the majority of older adults were not high risk for loneliness (36/47, 77%) and scored high-to-average for mental well-being (42/47, 89%). The data collected on the Lubben Social Network Scale indicated the majority of participants (37/47, 79%) had good social networks which includes connections to family and friends (Additional file 8).
Older adult interviews
We conducted interviews with six older adults. We identified eight themes from the interviews and these were agreeableness, connectedness, memorable substance of calls, recognition of value, self concept, effect of COVID-19 pandemic, mutually beneficial, and consistency. Each theme is described below and illustrative quotes are summarized in Table 3.
The theme, agreeableness, addresses older adult’s perspectives on the medical students they were paired with. Complimentary terms were used including warm, personable, easy to talk with, and polite. Being positive and upbeat were qualities that were welcomed by the older adults in their interactions with their student partners.
Connectedness emerged as a theme where the older adults described feeling that they had made a new friend, and that the student partner contributed to diminished feelings of isolation. Bonds were cultivated and this was signaled by the continuity of conversation from one week to the next over common areas of interest that were not necessarily related to their health status. When connections faltered, inconsistent communication (e.g. student forgetting to call, or calling on a different day) was a factor.
Memorable substance of calls
This theme describes the mutual sharing of diverse interests, experiences, and perspectives that enriched the conversations between the older adults and the student partners. Older adults discussed a wide range of subjects from everyday things such as books and pets, as well as identifying very specific areas of common interest. Topics also included checking on the older adults’ health and well-being.
Recognition of value
The recognition of value theme summarizes the older adults’ gratitude for the program and includes their overall feelings of appreciation. Sentiments included wishing the program would not end, indicating they would recommend the program to their peers, and indicating they hoped the program continued.
The theme, self concept, captures how older adults perceived their own nature and state of mind toward their current circumstances. Living alone and acknowledging that isolation was an issue identified by participants.
Effect of COVID-19 pandemic
COVID-19 altered the normal routine of lives and this theme encompasses how the pandemic affected the lives of the older adults. This included how their personal circumstances made them more vulnerable due to illness, or not having family members nearby.
This theme describes older adults’ impressions of how the program may have had benefits for the medical students and included recommendations for making it a part of the regular medical school curriculum.
The consistency theme highlights the importance the older adults placed on having the same student partner each week, and ensuring the conversations occurred on the same day and time each week. When this consistency was missing, the older adults' experience of the program was negatively affected.
Medical student questionnaires
Twenty nine medical students completed a demographic questionnaire (Table 1). None were lost to follow up. They also completed a questionnaire on knowledge of social isolation and attitudes towards seniors at the 12-week point in a retrospective post-then-pre method. All questions showed statistically significant results. Each question is summarized in Table 4.
Medical student interviews
We conducted interviews with five medical students. The seven themes that were identified from the interviews were 1) fulfilling, 2) impactful, 2) valuable opportunity, 3) connectedness, 4) empathy, 5) COVID-19 isolation, 6) career influence, and 7) barriers to care. Each theme is described below and illustrative quotes are summarized in Table 5.
The theme, fulfilling, illustrates the medical students’ perspectives on taking part in the program and making the phone calls to the older adults. Positive terms were used including rewarding and enjoyable.
The impactful theme describes the effect the students felt they were having on the older adult’s life and includes descriptions of the ways they believed they had made a contribution. For example, providing reliable information that countered confusing media reports.
This theme highlights the perception amongst students that this was a unique opportunity that reflected the difference between formal learning and experiences outside of the classroom or clinical setting.
Connectedness emerged as a theme where the students described looking forward to interacting with the older adults, as well as having a sincere interest in the person and in engaging with them.
The empathy theme described how this learning opportunity offered a more fulsome understanding of older adults’ experiences and contributed to an understanding of unique issues seniors faced during the COVID-19 pandemic.
This theme highlighted the student’s understanding that isolation was an issue that pre-dated COVID-19, but that the pandemic has made it worse.
The career influence theme describes a new or reinforced interest in caring for older adults or pursuing fields that include the care of older adults.
Our study presents evidence that the SSIPP program improved medical students’ perspectives on caring for older adults. The results were statistically significant and indicate that participation in this program was associated with strengthening knowledge of social isolation, attitude toward seniors, likelihood to engage in caring for older adults, understanding of the value in addressing social isolation among older adults, and the priority the students put on addressing social isolation. Our qualitative analysis of the medical students’ interviews provide further support that the experience had impact on influencing their careers and their current clinical practice. Medical students described actively asking more questions about social isolation and recognizing that social isolation would continue to be a problem post-COVID-19 for seniors. As well, the medical students perceived minimal effort was required for the phone call check-ins and indicated benefit to both their own sense of fulfillment and the older adult they were paired with was substantial. For older adults, the scores from the UCLA Loneliness Scale and the Warwick-Edinburgh Mental Well-being Scale did not change significantly over the intervention period. However, analysis of the interview data provides insights that the older adults genuinely looked forward to the phone calls and if a call was missed, it was described as disappointing. This finding is useful to planners in emphasizing the importance of regularity in making phone calls to older adults, for both day of the week and time of day, when recruiting medical students. It also reveals that the once-a-week phone call had benefit for this group, with factors that need further investigation.
Strengths and limitations of the study
Our mixed methods study combined quantitative data with qualitative interviews. The strength of this approach was that the outcomes reported in our quantitative analysis could be explained and contextualized with our qualitative data. For the medical students, the quantitative data showed a shift in perspectives and qualitatively offered insightful understanding to the interactions with seniors, including details of how it influenced their perspectives on their career and dealing with seniors in their medical practice. For the older adults, the qualitative data provided support that the program was beneficial to the participants. Our quantitative data did not show a change in loneliness or well-being through the use of our validated scales and this identifies a limitation of our study. Our group of seniors self-selected into the program and the people who chose to participate had scores for both the UCLA Loneliness Scale and the Warwick-Edinburgh Mental Well-being Scale that were not of concern for both loneliness and well-being. For the UCLA Loneliness Scale, the majority of older adults (36/47, 77%) were not considered at risk for loneliness. For the Warwick-Edinburgh Mental Well-being Scale, 89% (42/47) of the seniors scored as having average-to-high mental well-being and not considered at risk as well. This made it difficult to determine if our program has impact on loneliness and well-being. However, our qualitative analysis of the interviews with the older adults provides rich information that the program had value for them. Our qualitative themes highlight this and includes participants stating how important calls were to them (Recognition of Value theme), to being unhappy and disappointed when the calls were missed (Consistency theme). It is interesting to note that although some content of the calls were about health, such as helping to decipher media items related to COVID-19, the conversations were about everyday matters such as pets, neighbourhoods, and personal experiences. Some older adults commented that they were pleased at the opportunity to speak to someone much younger than themselves so that conversations were not about ‘aches and pains’. We had a small sample size and with the older adults, seven participants were lost to follow up. As well, the older adults were largely white (40/47, 85%) and had higher levels of education, with the majority holding a college or university degree (35/47, 74%). This reflects the recruitment strategy of seeking volunteers as participants rather than screening for specific participant characteristics.
Directions for future research
The results of this study are promising and suggest future studies would provide more insight on communication outreach programs for both older adults and medical students. Future research could look at identifying high-risk seniors during study recruitment to determine if a communication outreach program has a quantitative impact for factors such as loneliness or mental well-being. As well, it would be helpful to determine the effect of factors such as the length of intervention, or different COVID-19 lock-down levels, (e.g., broad allowance of activities, or restriction/closure of most businesses/organizations).
We found significant results that after the SSIPP partnership program, medical students’ perspectives were positively influenced and they were more likely to engage in a medical career focused on older adults. With an aging population, it is important to identify factors that contribute to optimal well-being. The older adults in our study indicated they found the communication outreach program valuable in our qualitative analysis and identified features that they considered of practical importance, such as the timing and consistency of calls. We did not find significant reductions in loneliness or mental well-being in older adults since the majority of our self-selected cohort were not at risk for either factor.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Student-Senior Isolation Prevention Partnership
National Academies of Sciences, Engineering, and Medicine 2020. Social Isolation and Loneliness in Older Adults: Opportunities for the Health Care System. https://doi.org/10.17226/25663. Accessed 27 July 2022.
Centers for Disease Control and Prevention. Loneliness and social isolation linked to serious health conditions. https://www.cdc.gov/aging/publications/features/lonely-older-adults.html. Accessed 27 July 2022.
Holt-Lunstad J, Smith TB, Baker M, Harris T, Stephenson D. Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspect Psychol Sci. 2015;10(2):227–37.
Crowe CL, Domingue BW, Graf GH, Keyes KM, Kwon D, Belsky DW. Associations of loneliness and social isolation with healthspan and lifespan in the US health and retirement study. J Gerontol A Biol Sci Med Sci. 2021;76(11):1997–2006 (May 8:glab128).
Ward M, May P, Normand C, Kenny RA, Nolan A. Mortality risk associated with combinations of loneliness and social isolation. findings from the Irish longitudinal study on ageing (TILDA). Age Ageing. 2021;50(4):1329–35.
Rico-Uribe LA, Caballero FF, Martín-María N, Cabello M, Ayuso-Mateos JL, Miret M. Association of loneliness with all-cause mortality: a meta-analysis. PLoS ONE. 2018;13(1):e0190033.
Meiboom A, Diedrich C, Vries HD, Hertogh C, Scheele F. The hidden curriculum of the medical care for elderly patients in medical education: a qualitative study. Gerontol Geriatr Educ. 2015;36(1):30–44.
Gomez-Moreno C, Verduzco-Aguirre H, Contreras-Garduño S, Perez-de-Acha A, Alcalde-Castro J, Chavarri-Guerra Y, García-Lara JMA, Navarrete-Reyes AP, Avila-Funes JA, Soto-Perez-de-Celis E. Perceptions of aging and ageism among Mexican physicians-in-training. Clin Transl Oncol. 2019;21(12):1730–5.
Higashi RT, Tillack AA, Steinman M, Harper M, Johnston CB. Elder care as “frustrating” and “boring”: understanding the persistence of negative attitudes toward older patients among physicians-in-training. J Aging Stud. 2012;26(4):476–83.
Student-Senior Isolation Prevention Partnership. https://www.ssipp.info/about-ssipp. Accessed 27 July 2022.
Johns Hopkins Medicine. Hopkins Medical Students Mobilize to Volunteer for the Community During COVID-19 Pandemic. https://www.hopkinsmedicine.org/news/articles/johns-hopkins-medical-students-mobilize-to-volunteer-for-the-community-during-covid-19-pandemic. Accessed 27 July 2022.
Harvard School of Public Health. Amid pandemic, Harvard Chan students connect with isolated local seniors. https://www.hsph.harvard.edu/news/features/amid-pandemic-harvard-chan-students-connect-with-isolated-local-seniors. Accessed 27 July 2022.
Office EE, Rodenstein MS, Merchant TS, Pendergrast TR, Lindquist LA. Reducing social isolation of seniors during COVID-19 through medical student telephone contact. J Am Med Dir Assoc. 2020;21(7):948–50.
van Dyck LI, Wilkins KM, Ouellet J, Ouellet GM, Conroy ML. Combating heightened social isolation of nursing home elders: the telephone outreach in the COVID-19 outbreak program. Am J Geriatr Psychiatry. 2020;28(9):989–92.
Morse JM. Approaches to qualitative-quantitative methodological triangulation. Nurs Res. 1991;40:120–3.
Bazeley P. Integrating Analyses in Mixed Methods Research. London: SAGE Publications Ltd; 2018.
Russell D, Peplau LA, Ferguson ML. Developing a measure of loneliness. J Pers Assess. 1978;42:290–4.
Tennant R, Hiller L, Fishwick R, Platt S, Joseph S, Weich S, Parkinson J, Secker J, Stewart-Brown S. The Warwick-Edinburgh Mental Well-being Scale (WEMWBS): development and UK validation. BMC Health and Quality of Life Outcomes. 2007;5(63):1–13.
Lubben J, Blozik E, Gillmann G, Iliffe S, Von Kruse WR, Beck JC, Stuck AE. Performance of an abbreviated version of the lubben social network scale among three European community-dwelling older adult populations. Gerontologist. 2006;46:503–13.
Morley JE, Vellas B, van Kan GA, Anker SD, Bauer JM, Bernabei R, Cesari M, Chumlea WC, Doehner W, Evans J, Fried LP, Guralnik JM, Katz PR, Malmstrom TK, McCarter RJ, Gutierrez Robledo LM, Rockwood K, von Haehling S, Vandewoude MF, Walston J. Frailty consensus: a call to action. J Am Med Dir Assoc. 2013;14(6):392–7.
Verhagen T, van den Hoff B, Meents S. Toward a better use of the semantic differential in IS research: an integrative framework of suggested action. J Assoc Inf Syst. 2015;16(2):108–43.
Rockwell SK, Kohn H. Post-then-pre evaluation. J Ext. 1989;27(2):1–7.
Lincoln Y, Guba E. Naturalistic inquiry. Newbury Park, CA: Sage Publications; 1985.
Guest G, Namey E, Chen M. A simple method to assess and report thematic saturation in qualitative research. PLoS ONE. 2020;15(5): e0232076.
We would like to thank Geoffrey Sem and Monisha Persaud for their important contributions. We would also like to thank all of the older adults and medical students that volunteered for this study.
This research received no external funding.
Ethics approval and consent to participate
The University Health Network Research Ethics Board (reference 20–5332) awarded ethical approval. All medical student participants gave written informed consent. Verbal consent was obtained from all older adults. Before taking part in the interviews, all participants gave informed consent to audio recording of the interviews and pseudonymised use of the data. All methods were performed in accordance with the relevant guidelines and regulations, i.e., the Declaration of Helsinki.
Consent for publication
The authors declare that they have no competing interests.
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Demographic questionnaire – Older adult participants. *Question 6 is the Lubben Social Network Scale.
UCLA Loneliness Scale and Warwick-Edinburgh Mental Well-being Scale.
Demographic questionnaire – Medical student participants.
Questionnaire for Medical Student Participants.
Interview guide – Older adult participants.
Interview guide – Medical student participants.
Thematic saturation of themes.
Lubben Social Network Scale Scores.
UCLA Loneliness Scale and Warwick-Edinburgh Mental Well-being Scale Scores for Older Adults.
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Moonen, G., Perrier, L., Meiyappan, S. et al. COVID-19 pandemic partnership between medical students and isolated elders improves student understanding of older adults’ lived experience. BMC Geriatr 22, 636 (2022). https://doi.org/10.1186/s12877-022-03312-z
- Medical students
- Cohort studies