People with Alzheimer’s disease progressively lose their ability to voluntarily retrieve personal memories, but a new Danish study using a novel testing method that mimicked real-life scenarios showed that Alzheimer’s patients were able to involuntarily recall memories with the help of videos and music connected to their youth.
In a paper published Feb. 10 in the Journal of Applied Research in Memory and Cognition, researchers from Aarhus University in Denmark found that older adults with Alzheimer’s were able to spontaneously report memories and emotional reactions and show a change in heart rate in response to viewing so-called nostalgic media dating from their youth. The results suggest that involuntary retrieval may be an alternative route for accessing the personal past of people with Alzheimer’s.
Katrine Rasmussen, a postdoctoral researcher at the Center on Autobiographical Memory Research at Aarhus University and lead author of the paper, told The Academic Times that this study examined autobiographical memory in people with Alzheimer’s disease in a novel way, in that it focused on personal memories coming to mind spontaneously, which has not been researched previously.
“The findings advance our understanding of how retrieval processes may influence autobiographical memory in the disease, by demonstrating that patients often engage in spontaneous remembering,” she said.
There are currently no effective medical treatments for Alzheimer’s disease or other types of dementia, which has led to an increased focus on developing psychosocial interventions aimed at reducing loss of functions and increasing quality of life for these patients. The decline in autobiographical memory in Alzheimer’s is partially due to executive dysfunction, which impairs the brain’s ability to deliberately search for memories.
Previous studies on the subject have relied on methods where researchers specifically request memories to be recalled in response to devices like a cue word, retrieving memories in a controlled search.
Involuntary autobiographical memories typically arise through automatic associative processes in response to real-world cues like a song on the radio, bypassing the controlled processes needed for voluntary memory retrieval. But they are notoriously difficult to study because they are uncontrolled, according to the researchers.
For the current study, the researchers developed a novel testing method to simulate the way involuntary autobiographical memories happen in everyday life. The study involved 21 patients who had been diagnosed with mild or moderate Alzheimer’s disease and 22 healthy older adults who did not have a memory disorder. The mean age of the total sample was about 78 years old.
All participants watched six-minute video clips on a tablet in the company of a researcher, with no prior information given about the videos or the purpose of the study. Any verbal comments the participants made during or after watching the video clip were spontaneous, and were recorded and later analyzed by the researchers.
The videos were produced for the study to stimulate a sense of familiarity using film footage and music from the participants’ youth in the 1950s and 1960s. They were specific to Danish culture and depicted common activities and social contexts from the time period, including well-known actors, objects and songs.
“Film viewing is associated with relaxation and seldom demands full attention, which are conditions thought to be optimal for experiencing [involuntary autobiographical memories],” the authors said.
The experiment split the participants into two conditions. One group only watched the video clips, while the second group was first asked to reminisce and recount their life story before viewing the videos. Both groups contained a mix of healthy participants and participants with Alzheimer’s disease. The researchers hypothesized that asking for voluntary reminiscing would make the adults more prone to verbalize their involuntary autobiographical memories during the video task.
Across both conditions, the participants made 164 verbal utterances during the task that the researchers considered to be involuntary autobiographical memories, defined as spontaneous comments that included memory content with a personal reference.
Ten of the 43 total participants generated between 7-12 of these types of memories, while 25 participants yielded between 1-6 memories and eight participants produced none during the task. Participants with Alzheimer’s provided more involuntary autobiographical memories overall than the healthy adults, and had more verbal and behavioral expressions of emotions while watching the videos. Across both groups, more memories were elicited from the condition that asked participants to first reminisce about their life.
“[Alzheimer’s] participants consistently generated more spontaneous responses to the films than healthy controls across both conditions, suggesting that while the nostalgia films were effective in triggering spontaneous reactions and [involuntary autobiographical memories] in both groups of participants, the [Alzheimer’s] group was particularly responsive to the material,” the authors said.
The researchers also measured physiological changes to participants’ heart rate and electrodermal activity, which refers to small changes in electrical characteristics of the skin. They wore a wireless device on their wrist that collected their physiological data.
The researchers expected that watching the videos would reduce participants’ heart rate and increase their electrodermal activity, reflecting positive emotions. Alzheimer’s patients had a higher physiological reaction to the films than the healthy group, showing a significant deceleration in heart rate and the expected numeric increase in skin conductance levels during the task.
The results support the idea that spontaneous retrieval is relatively preserved in Alzheimer’s disease, likely due to minimal demands on controlled processes affected by the disease, according to the paper. Rasmussen noted that seeing the adults with memory disorders outperform the healthy participants was a “highly unusual” finding.
But the deficits in inhibitory control in Alzheimer’s patients make them less able to hold back emotion-expressive behavior when being exposed to emotionally arousing material, which may not be true for the healthy adults, the researchers said. The heightened response in Alzheimer’s patients may also be due to the videos activating memories and emotional reactions that were not readily accessible to the patients through voluntary retrieval.
Rasmussen said the findings indicate that physiological measures can be used to test implicit responses in Alzheimer’s patients, which might be particularly important in the later stages of the disease when communication abilities are compromised. And the group’s responses suggest that memory performance is not static, and that providing adults with Alzheimer’s with the right cues can make it easier to access their memories.
The study, “Using Nostalgia Films to Stimulate Spontaneous Autobiographical Remembering in Alzheimer’s Disease,” was published Feb. 10 in the Journal of Applied Research in Memory and Cognition. Katrine Rasmussen of Aarhus University was the lead author. Sinué Salgado, Marianna Daustrand and Dorthe Berntsen, all of Aarhus University, served as co-authors.