The Many Ways Music Supports Memory in Alzheimer’s


Alzheimer’s disease is a neurodegenerative disorder characterized by problems of memory, attention, and other cognitive functions. The disease progressively worsens, and though medication can slow down the progression of the disease, there is no cure. Alzheimer’s currently affects an estimated 46.8 million people worldwide. As the population ages, this number is estimated to double every 20 years  Therefore, there is considerable interest in finding easy access methods for treatment of symptoms, and for maintaining the quality of life of affected individuals.

Listening to music may be one way of addressing cognitive difficulties associated with Alzheimer’s, especially problems with memory. There is a lot of anecdotal evidence for persons with severe dementia suddenly “coming back to life” upon hearing a familiar tune. These stories are corroborated with studies showing that areas of the brain related to musical memory are preserved in Alzheimer’s disease.

Recently, a great review (1) summarized findings on the different ways in which music can support cognition, and especially memory functions in Alzheimer’s, as well as the neural mechanisms that may underlie these effects.

The authors propose that one of the reasons why music may be so effective in stimulating cognitive function in general is because music activates the brain so extensively, ranging from areas related to auditory perception, attention, and memory to those for emotion and reward. Interestingly, the very same brain structures that are damaged in Alzheimer’s, are activated by music. In the case of memory enhancement, one reason for the positive effects of music may be its ability to evoke emotions.  As we reported in a recent blog post, music is specifically good at evoking memories from long-term storage, such as past life events. We’ve all probably experienced this – being suddenly transported back in time to specific life events after hearing a musical piece tied to those specific memories. Music can thus activate the affective fingerprint of the memory, bringing it to mind more vividly than in other forms of remembering. The authors of the review suggest that using this special power of music to evoke emotionally vivid autobiographical memories could be an effective way to support the feeling of identity and the sense of self that are often compromised as Alzheimer’s progresses.

But why exactly does music effect Alzheimers symptoms in these ways? What are the neural mechanisms underlying music-induced memory enhancement?

The authors of the review present three suggestions:

1. The effects that music has on dopamine
The dopaminergic system is involved in the sensations of pleasure and reward and also in learning of new information. Music listening has been found to activate neural systems related to dopaminergic release, and could thereby support learning-related cognitive functions as well as enhance the motivation for learning.

2. The effects that music has on arousal
Loud music with fast tempo has been found to increase arousal, as indexed by increase in heart rate, blood pressure and breathing, and relaxing music with slow tempo and volume does the opposite. As the level of arousal affects cognitive function, the effects that music has on the autonomous nervous system could translate to enhancement of cognitive function. Namely, reducing anxiety that is common in Alzheimer’s with relaxing music might help support cognitive function such as attention. However, the effects depend highly on individual factors and therefore for some, increasing arousal with uplifting music may best provide support for cognitive function.

3. The effects that music has on the default mode network
The default mode network (DMN) is a large-scale network of brain areas that is active when people are awake, but not in a goal-oriented state, involved in introspection, remembering, fantasy or creative thought. The DMN is active for instance when you are on the subway, not staring at your smartphone, but just letting your mind wander, or when you are taking a long bath or a slow walk, not focusing your thought on anything in particular but letting ideas pop into your mind spontaneously. In Alzheimer’s, the connections between the areas of the DMN deteriorate, disturbing its function and possibly resulting in problems with memory. Conversely, music listening has been associated with increased functioning of the DMN. Therefore, music could be a way to support healthy functioning of this network.

In summary, music may have many routes to support memory function in Alzheimer’s. Music listening can evoke autobiographical memories, enhance the functioning of brain systems important for learning, increase or decrease arousal, as well as activate the functioning of a large-scale network important for memory. Incorporating music listening into the everyday lives of Alzheimer’s patients with sensitivity towards individual differences, and music preferences might provide an easy and cost-effective way to support memory functions.

Written by Ketki Karanam

References

  1. Peretz, I., & Zatorre, R. J. (2005). Brain organization for music processing. Annu. Rev. Psychol., 56, 89-114. http://dx.doi.org/10.1146/annurev.psych.56.091103.070225
  2. Peck, K., Girard, T. A., Russo, F., & Fiocco, A. J. (2016). Music and Memory in Alzheimer’s Disease and The Potential Underlying Mechanisms. Journal of Alzheimer's Disease, (Preprint), 1-11. http://dx.doi.org/10.3233/JAD-150998