Friday, March 13, 2009

Doidge (Neuroplasticity) review - part 2 (Taub)

Doidge devotes a chapter to the work of Edward Taub. I think Taub's ideas are simple but brilliant. He developed a treatment called "constraint-induced movement therapy" which appears to be remarkably effective to help with recovery from strokes and other injuries.

The simple idea is to restrain the normal limb, almost continuously, for at least weeks at a time, after a neurological injury. Otherwise, the normal limb will compensate for the affected limb. If the normal limb is constrained, the brain itself will develop new pathways to improve the function of the affected limb.

This treatment has good evidence-based support:

http://www.ncbi.nlm.nih.gov/pubmed/18077218

{this 2008 study is from Lancet Neurology, one of the top journals in neurology}

http://www.ncbi.nlm.nih.gov/pubmed/17077374


{another very important study from 2006 in JAMA}

I'm curious about the applications of this sort of therapeutic idea to psychiatry. Psychiatric symptoms can be like other neurological impairments, and the psychoanalytic phenomenon of "defences" may be analogous to the tendency for a neurologically-injured person to favour the non-affected limb, while the affected limb loses more and more function. A psychological therapy which challenges defences may be something like a Taubian "constraint-induced movement therapy" for the mind.

Importantly, in order for Taub's therapy to work, the constraint has to be applied almost continuously during waking hours, for at least weeks at a time. It is an immersive experience. It is an interesting challenge to find more psychological therapies that can be "immersive" in this way.

Doidge (Neuroplasticity) review - part 1 (Merzenich)

This post begins my review of Doidge's references from his book on neuroplasticity.

The first references I have looked through pertain to the work of Michael Merzenich. He has done very interesting research, dating back 4 decades, a lot of it having to do with studying the auditory cortex, and how it changes in response to stimulation of various sorts during different phases of development. Also he done major work researching and developing cochlear implants for treating hearing loss.

His 2006 article about using a "brain plasticity based training program" to improve memory in older adults (http://www.ncbi.nlm.nih.gov/pubmed/16888038) is interesting and encouraging, yet it warrants a close look at the actual results: the memory improvements from this technique were very modest (though significant), also the control groups were both quite passive (one group just looked at DVD videos, the other had no "intervention" at all). It would have been much more interesting to me to see an active control group in which the individuals would be doing simple memory exercises or other active intellectual stimulation for the same length of time. Because this type of active control was absent, the results may aggrandize the specific form of skill training described in the study; this skill training regimen is now being marketed, and money is surely disappearing from the pockets of many people, including many elderly people who may not have an abundant financial reserve. This makes me especially less enthusiastic about the results. I have no doubt that active mental exercise changes the brain through "plasticity" but I have to wonder if we have to sign up for the deal ("save 20% and get free ground shipping!") with this specific technique to achieve this. Perhaps signing up for a book club, memorizing poetry, and playing chess daily, would accomplish similar results. I would like to see what the evidence has to say about this. His website is interesting to look at, has a few mental exercises to check out, the style of which I think really is quite positive and imaginative. I will be curious to see if his approach--and variations of it-- could be specifically helpful in treating disorders such as autism. But I don't see good clinical data out there yet.

As an amateur musician, I have found that "ear training" is probably the most important, but often least taught or practiced, form of mental development for improving musicianship. Merzenich's exercises clearly focus on "ear training" as a significant component. Here's his website for you to check it out yourself: http://bfc.positscience.com/

Here's a link to a program you can acquire, designed for music students, which develops musical ear-training ability much more thoroughly, in my opinion (I recommend this to all musicians): http://www.earmaster.com/

Tuesday, March 10, 2009

Neuroplasticity

This is an important book which I highly recommend:
The Brain that Changes Itself, by Norman Doidge (Penguin, 2007).

Doidge is a psychoanalyst who has done a fine job compiling evidence from recent neuroscience research, and from some older but neglected neuroscience research, that the brain has a tremendous capacity--a capacity which is arguably its most basic, core, innate quality-- for change and adaptation.

The idea of the brain as permanently "hard-wired" is refuted, with solid evidence.

Many of these ideas I have always felt to be obvious truths. For example, it seems an obvious necessity that the brain would have to build new connections in order to form any new thought, experience any new feeling, store any new memory, learn any new skill. But the degree to which whole areas of the brain can "re-wire" themselves is extremely interesting, and the evidence Doidge presents is very convincing.

Also, it has always been an obvious truth to me that any kind of sensitive neuroimaging device would of course demonstrate changes following a successful course of therapy (or of any other sort of learning or substantive life change).

The therapeutic applications based on this book are numerous, here are a few I can think of:

1) structured, intensive practice could lead to far greater effects than what has previously been assumed. The brain itself, as well as people in society, informed by culturally-based attitudes, tend to "work around" problems if the situation allows, whereas it can be the case that the problems themselves can be solved directly under the right conditions. For example, if an English-speaking person moves to a small town in a foreign country, that person will quickly learn that new foreign language, if it is necessary in order to survive. But if there are numerous English speakers in that small town, that person may not learn much of the new language at all.
We may need a type of immersive, constrained experience in order to compel our brain to develop a new faculty.

2) structured, intensive activities that have become part of a cultural norm (e.g. internet use, TV watching, etc.) could substantially alter the brain's connectivity and functionality, to optimally adapt to these new media. This could serve us well, culturally--but it may come at a cost of reduced functionality in media away from the TV or internet, particularly with respect to sustained attention, other intellectual and emotional faculties, and various types of social interaction.

3) Addictive processes are fed by the brain's capacity to adapt, to "re-wire" itself to expect a frequently reinforced behavioural pathway. "Un-learning" addictive behaviour once again may require a massive amount of work, akin to learning a new language.

--I have yet to review all of the references cited in this book. I think the primary source data will be important to go through in detail. There are some areas and claims that I think may possibly be overstated, in my opinion. But first I would like to review the evidence directly. I actually find the term "neuroplasticity" somewhat annoying, especially when therapeutic ideas are labeled "neuroplasticity-based treatments", etc. --I would say in response that ALL therapy, of ANY sort, is of course "neuroplasticity-based", so such lingo is unnecessary, and rings of salesmanship to me (indeed, there are several corporate ventures mentioned in the book). What matters most is the new types of therapeutic ideas that have been conceived by some of the researchers cited in the book, and how well they can work for very entrenched problems.


In the meantime, I do recommend Doidge's book highly.

Friday, March 6, 2009

Physicians in need of help

There is a high incidence of psychiatric problems in the medical community. Physicians may have a difficult time finding help. There are a variety of reasons for this, the most common of which is that the sources of help may all involve people the physician knows personally.

In BC we have something called the "physician health program", which is a resource especially for physicians in need of help. Here is the website:
http://www.physicianhealth.com/

Hopefully other communities have similar programs.

If a hospital admission is needed, it may be desired to arrange this in a different place, if privacy or confidentiality issues are major concerns.

Thursday, March 5, 2009

Exercise benefits Quality of Life




You can click on the chart to expand it; the chart above is from a randomized, controlled, 2009 study by CK Martin et al., published in the major journal Archives of Internal Medicine, in which 6 months of regular aerobic exercise is shown to improve numerous domains of quality of life, including mental health, vitality, and social functioning, in a group of 430 sedentary postmenopausal women.

To interpret the chart, look at each symptom domain. There is a control group (which did not exercise), then groups which exercised approximately 1, 2, and 4 hours per week, with the groups which exercised more represented towards the right-hand side of the chart.

The improvement in quality of life did not depend on any weight loss occurring with the exercise. And it appeared that as little as an hour a week of exercise was beneficial, though 2-4 hours per week were slightly more beneficial than just one. Here's a link to the abstract:

http://www.ncbi.nlm.nih.gov/pubmed/19204218

As a cautionary note, I find "exercise addiction" to be another potentially serious problem, which could substantially REDUCE quality of life. The above data support a very modest amount of exercise, in the order of 4 hours PER WEEK , for improving quality of life.

I strongly encourage people to exercise. I believe it is basic self-care, a requirement for health.

It is intuitively obvious that exercise would be beneficial for psychological health, and be a good potential therapy for depression or anxiety.

Yet, there is an important recent study of over 5000 Dutch twins, which shows that exercise did not have a direct influence on anxiety or depression. This is a surprising result, but it needs to be taken seriously. Twin studies are very powerful in research, since they look at individuals who are genetically identical -- any differences in symptoms would have to be caused by environmental factors, as opposed to genes. Twins who exercised more than their co-twins were not in fact any less anxious or depressed. (Actually, as I look at the results directly, I see there was a small association, but it was judged to be "non-significant")

The study did confirm that people who exercise are, on average, less anxious and depressed than those who do not exercise. But the conclusion was that this is not because exercise improves emotional symptoms -- it is because there is a genetic factor which predisposes some people both to exercise more, and to have fewer psychological symptoms.

Here is a link to the study:
http://www.ncbi.nlm.nih.gov/pubmed/18678794

On the other hand, there are a few studies which show a therapeutic effect of exercise on psychological symptoms:

http://www.ncbi.nlm.nih.gov/pubmed/17846259

http://www.ncbi.nlm.nih.gov/pubmed/11020092

The above studies show a beneficial effect of exercise, of at least 3 times per week, 30 minutes per session.

Why are there seeming contradictions with these studies?

It may be because the twin study was looking at individuals' intrinsic exercise behaviours, as determined by their life circumstances & inherited factors. Variations in exercise between twins may have been due mainly to opportunity or chance.

The other studies were looking at exercise as a formally prescribed treatment. This would involve a directed change of behaviour, outside of what the individuals would normally do on their own.

It could be that prescribed changes of behaviour, if adhered to for health reasons, could have a stronger therapeutic effect than the behaviours engaged in for other reasons.