Tuesday, October 21, 2014

Music evoked autobiographical memory after severe acquired brain injury

Baird, A., & Samson, S. (2014). Music evoked autobiographical memory after severe acquired brain injury: Preliminary findings from a case series. Neuropsychological Rehabilitation, 24(1), 125-143. doi:10.1080/09602011.2013.858642

Summary:

This study analyses the relation between music and autobiographical memories in subjects who had acquired brain injuries ABI. The concept of Music evoked autobiographical memories MEAMs refers to the ability of a person to recall specific memories while listening to very specific songs. This concept has been already explored by several authors, especially with patients with Alzheimer Disease (Janata et al. 2007, El Haj et al. 2012). This is the first study that focuses in people with brain damage caused by accidents.

Baird and Samson selected 5 subjects with brain injuries caused by motorbike accidents, cardiac arrests, fall from building and a suicide attempt. All of them were carefully selected as well as other persons to be used as control subjects (wives or siblings with a close relation with the subjects). The selection process consisted in choosing people with similar characteristics in terms of age, the cause of the injury and severity, their musical “experience” and the type of memory impairment (anterograde: verbal/visual). They also evaluated their emotional state to know if they suffered anxiety, depression or stress. Only one person was in a deep depression but the rest were practically normal and other person had some musical experience (bass guitar player).

Each subject had to answer a questionnaire to rank the familiarity with the songs, their likeness, if they remembered some specific event, and if this memory was positive or negative. Each person had to listen 30 to 60 seconds of random hit songs from 1961 to 2010. Except for case 5 the rest of the patients experience consistent MEAMs. It was determined that the fifth patient had impaired pitch perception and even though he remembered and even sang some of the songs he did not reported any memory. The rest of the patients reported vivid memories related with a person or specific life event and were typically positive and sometimes neutral. In terms of the amount of memories evoked it was discovered that the severity of the trauma was not related with a low number of MEAMs, in fact patients with more severe traumas reported more MEAMs.

The authors recognize that more tests should be done before having a clear understanding of their results, nevertheless these preliminary results show that there is a promising potential for music to be used towards cognitive rehabilitation in patients with acquired brain injuries.

Reflection:

It is clear from this study and from previous studies in Alzheimer Disease patients that there is a very strong relation with MEAMs and the patient emotional status. Additionally, memories become more vivid and are recalled quickly with the auditory stimuli. In some cases where the patients had a connection with the lyrics of the songs this effect becomes even stronger. During the detailed analysis of case 4 the descriptions provided by the patient’s wife were extremely detailed and specific while his husband just remembered certain details. The authors do not provide an explanation to this phenomenon but it might be completely unrelated to the brain injury. This difference in recalling specific events might be just related with the person’s ability to remember details. Frequently, we hear about couples where the female remembers very clear details of a particular moment or event such as the clothes that were wearing or certain specific words or feelings while their partners remember vague details.

It will be also interesting to see if the patients have other responses to the music (i.e. Chills) at the time they recall the memories. It has been argued that the intensely pleasurable responses to music are strongly related with the limbic region (Blood and Zatorre, 2001). In three of the cases analyzed in this study the patients head impacted damaging certain part of the brain, therefore analyzing the relation with the stimuli and the brain activity would be helpful to determine the different evoked memory capabilities.


Going back to the fifth patient who clearly knew the songs but reported no memories and no familiarity, it is worth to notice the importance of pitch perception over the rhythmic or the lyrics. It would be useful to make another set of tests and modify the pitch of the songs to evaluate if patients with acquired brain injuries can still recall the songs and evoke memories. I believe that the relation between the previous musical experiences may also represent a drastic difference in the amount of MEAMs. Musicians not only trend to appreciate and hear more music, but they also trend to analyze it unintentionally therefore they might be able to recognize more melodies identifying them as familiar, nevertheless this possible increase in familiarity might not be correlated with likeness or with memories.

Anne J. Blood, Robert J. Zatorre (2001),Intensely pleasurable responses to music correlate with activity in brain regions implicated in reward and emotion, Proc Natl Acad Sci U S A. 2001 September 25; 98(20): 11818–11823. doi: 10.1073/pnas.191355898

1 comment:

Carina Freitas said...

Hi Ricardo!
Thank you for your post.
As you mentioned, in the present article authors used familiar music to elicit autobiographical memories (MEAMs) in patients after acquired brain Injury (ABI). Although this is a preliminary study with a small number of 5 patients, the findings are quite exciting, and it re-emphasizes the great potential of music to be used in cognitive rehabilitation settings.
It was of no surprise to read that more liked and more familiar songs were those that evoked more autobiographical memories. The term “familiarity” signifies that an individual has been previously exposed to the same type of stimulus. In case of songs, the more you listen, the more familiar the song becomes, and consequently, the more it is encoded in the auditory memory.
However, what puzzled me more was the case of patient number 5, who had no MEAMs and impaired pitch perception. As outlined in the article previous studies have reported that the recognition of familiar melodies is more dependent on pitch than rhythm perception, which perhaps explains this discrepancy.