On Mon, 26 Feb 2001, Jeff Ricker wrote:
> I often talk about brain plasticity being greatest at younger ages. The
> following article from Medscape suggests that there may be some
> important limitations to this generalization. I know that I have read
> about this somewhere else recently, but I don't think it was on TIPS.
> Please forgive me if I am wrong about this and someone else recently
> sent a similar article.
>
> ----------------------------------------------
> http://neurology.medscape.com/reuters/prof/2001/02/02.21/20010220clin012.html
>
> Functional Recovery in Brain-Injured Children Not Always Maintained Long
> Term
>
> SAN FRANCISCO (Reuters Health) Feb 20 - Children who suffer brain injury
> at an early age usually recover language and cognitive abilities
> rapidly, contributing to the conventional view that the brain manifests
> its greatest plasticity at younger ages.
>
> But time often reveals impairment <snip>
>
> Functional brain imaging scans in a series of eight patients with a
> history of severe brain injury 3 years prior, but before age 9, revealed
> hyperactive brains, Dr. Chapman said. That is, when compared with eight
> normal, age-matched controls, the scans revealed increased regional
> blood flow in the left mesial frontal cortex, the globus
> pallidus-putamen-thalamus, and the right visual cortex, with decreased
> regional blood flow in the right cerebellum.
>
> In a pilot study of cognitive communication intervention involving two
> patients with histories of severe brain injury and two normal,
> age-matched controls, Dr. Chapman's group provided 10 hours of training
> in making inferences over a 2-week period. Brain scan evidence suggests
> that the training causes a marked increase in the neuronal recruitment
> for the task, she reported.
Two points related to this. First, a fishing trip on the brains
of eight patients known to have suffered severe damage doesn't
provide the most convincing of evidence. Let Dr. Chapman pick out
damaged brains from a random set of normal and damaged solely
on the basis of blood flow measurements, and I'd be more
impressed. Similarly, show me that the inference training makes a
difference in their academic performance and I'll start to pay
attention.
But the larger issue of greater plasticity of the brain when
young is a more interesting issue. It may well be a myth. My
impression is that the studies showing better recovery after
brain damage at a early age are confounded with length of
recovery time: the younger the age at which damage occured, the
longer the time for recovery before assessment. When recovery
time is controlled, the alleged advantage for early damage
disappears.
References would be nice, of course, but I must plead writing
from home.
-Stephen
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Stephen Black, Ph.D. tel: (819) 822-9600 ext 2470
Department of Psychology fax: (819) 822-9661
Bishop's University e-mail: [EMAIL PROTECTED]
Lennoxville, QC
J1M 1Z7
Canada Department web page at http://www.ubishops.ca/ccc/div/soc/psy
Check out TIPS listserv for teachers of psychology at:
http://www.frostburg.edu/dept/psyc/southerly/tips/
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