Tuesday, December 2, 2008

Neuroplasticity and functional recovery

Baker, Felicity and Edward A. Roth. “Neuroplasticity and Functional Recovery: Training Models and Compensatory Strategies in Music Therapy”. Nordic Journal of Music Therapy, 13 (1) 2004, pp. 20-32.

By: Devon Fornelli

This article discusses issues regarding recovery of function after neurological damage following a Traumatic Brain Injury. Also mentioned is research in music perception and production, as well as specific music therapy interventions address the restoration of function.
The eventual goal would be to address the timing for introducing each treatment strategy and how this would affect potential outcomes for the client. A problem is that neurological fields and MT fields rarely share information or consult each other. This article focuses on Neuroplasticity and how Music Therapy training affects this. The information addresses how Music Therapy clinicians deal with behavioural compensation strategies versus restoration of function.

There exists a dilemma for therapists: develop compensatory skills based on spared function or focus on restoration of function (reducing impairment to return to normality).
There are instances when focusing on compensatory skills is detrimental to the recovery of a skill if the restoration of function is possible. If the decision is made to develop a compensatory skill then the ability to recover the original skill is lost. An example is if the ability to move your right thumb is hindered and to compensate you develop skills using your other fingers. The result will be that your thumb will not recover function since you are compensating for that injury by developing new functions.

There remains a lot to be studied on effect of Music Therapy on cerebral reorganization/neuroplasticity.
In this paper, studies were identified that report on developing compensatory function which illustrate how MT can be framed in a philosophy of practice.
Again, behavioral compensation is where an individual adopts the use of skills which were not used prior to the injury.
Compensation is a term from the 1930s – coined by Emerson and Goldstein. Goldstein proposed that recovery (based on compensation) occurs as a consequence of change in strategy rather than an amelioration of the deficit. Rehab in a compensatory framework should focus on using intact capacities to perform tasks vs. decreasing the impairments by focusing on restoring function to the injured skill.
For clients with poor memory, MT will use a diary as a strategy and set tasks for clients to complete between sessions.

A clear illustration of compensatory skill development is for clients who are hemiplegic – one side has function – and therefore that side takes over tasks the other side used to perform.

Another situation where Music therapy was useful is cited by Baker: a client needed to remember safety with wheelchair – not go down stairs, put on brakes etc. Baker composed a song that the client used as a cue for safety – music as a cue was the compensation for remembering what to do.

Origins of the term Neuroplasticity
Cotard first makes mention of NP (mentioned in Benton and Tranel) – when he noticed that children with worsening atrophy to the left hemisphere of the brain didn’t become aphasic – because the brain adapted - what he called neural substrate reorganization – now called neuroplasticity.
Kolb and Gibb added to this when they analyzed how glial cells increased in number and size within animals whose brains were damaged after they were exposed to an enriched environment (toys, challenges, etc.). The change in Glial cells is correlated with changes in neuronal morphology – and it is thought that they stimulate neuronal changes.
Further, animals can adapt to cortical injury by using other remaining circuitries (K and G). As well, Elbert, Pantev, Weinbruch, Rockstroh and Taub found that string players showed increase in cortical representations between hands (left thumb vs. other fingers and vs. rh) suggesting that repetitive experience in one area can increase the cortical representation of that function in the brain. This helps indicate that even adults are capable of dynamic reorganization in cortical topography after changes/ injuries in the hand or surgery on webbed fingers etc.
Restoring deficit – using Neurologic Music Therapy (NMT) – This article mentions Thaut’s research which focused on the perception and production of music and its effects on brain and behavior: his research tried to link/ parallel musical and non musical processes in the brain. Thaut was interested in research effect of auditory rhythm on simultaneous motor functioning. This all was in order to help build rational hypotheses relating to how music influences non-musical functioning.

Music Therapies used to retrain motor functioning after brain injury or deterioration:
Treatment programs use Rhythmic Auditory Stimulation (RAS), Therapeutic instrumental Music Performance (TIMP), and Patterned Sensory Enhancement (PSE) (Thaut). RAS was found to be helpful in treating problems in gait training (walking rhythm)

This article briefly mentions other studies involving recovery of function: Fields (1954 – regain use of affected limbs), Livingston (1996 – recovery of finger coordination using keyboard skills), and others.
Magee (1999) and Baker (2000) used melodic cues for aphasics in memory related tasks. When they could not generate the word, they could self-generate the melody and thus cue an association to the word.

As stated earlier, there are times when using compensatory methods is detrimental to recovering lost function: there are cases where compensatory systems may benefit short term skills, but inhibit activity of damaged circuits for long term recovery.
Conclusions: In general, the goal of utilizing Music therapy is for the amelioration of deficits during the initial stages of recovery from a brain trauma. It is when clients are unable to restore the preferred mode of performing a skill that compensatory skills should be considered in order to train another skill to replace the lost function.
The author stresses that further research is necessary to pinpoint when certain music therapies should be introduced during specific stages of recovery. Also, this timeline needs to address when it is optimal to introduce therapies in relation to the severity of brain injury.

As an individual who has lived through a TBI, I realize that there were some skills that I lost from my injury and there were salvageable. As an example, I used to have a very strong aural memory for memorizing music, lines from dramatic plays quickly. That is a skill I have lost. What has compensated for this is the development of analytical and kinesthetic memory to aide in memorization.

I agree with Baker’s conclusions that therapists - and potentially clients too – must be flexible when organizing a program of therapy in order to determine whether or not to pursue restoration of function or developing a compensatory skill. Also, it will beneficial to determine a timeline or a set of criteria that will help to determine when certain therapies can be introduced to be most beneficial throughout a program of therapy.

By Devon Fornelli

No comments: