Healing from strokes?

Eric Wassermann ewass at helix.nih.gov
Fri Jan 6 09:46:00 EST 1995

In article <D1yKGu.Au8 at murdoch.acc.Virginia.EDU>,
mlm2s at galen.med.Virginia.EDU (Mallory Leslie McClure) wrote:

> How is it possible to have a patient have a stroke ( resulting in
> fluent aphasia) and show no deficits two months after the
> stroke?  I thought that patients always had some residual
> damage following a stroke. What role does the age of the
> patient play in the outcome?
> --
> Mallory L. McClure
> University ofVirginia School of Medicine class of 1997
> mlm2s at virginia.edu

1) Not all deficits result from irreversible processes like neuronal
death--for instance a set of acute changes following ischemia
(colloquially known as "edema") cause deficits, but reverse within days. 
Also neurons in the so-called "penumbra" of the ischemic area may suffer a
reversible insult and cease to function normally for some time.

2) Recovery from deficits produced by cortical lesions is the rule rather
than the exception because of the strong tendency for the cortex to
reorganize following injury.  This is oversimplifying a bit, but the
location of function on the cortex is not hard-wired, but rather
maintained by a dynamic process.  This flexibility underlies some
important types of learning and also provides significant potential for
plasticity following lesions.  Language seems to be somewhat robust
compared to say, movement.  Perhaps this is because it does not rely on a
highly fixed set of connections like the connection of the motor cortex to
the corticospinal tract.

3) And you're right.  _Nobody_ recovers completely from a stroke. Nobody
ever feels the same. Very few people go back to full time work.  They may
walk and talk normally in the clinic, but if you are a careful clinician
who listens to people, you will nearly always hear about deficits and
often find them if you are imaginative enough to go beyond the standard
exam they teach you in medical school (and neurology residency).

4) As far as age goes, the younger the better, but since plasticity takes
place on many levels, different processes can be recruited in different
individuals. I have seen old folks make remarkable recoveries, seemingly
by dint of hard work and indomitable attitude.  On the other hand, young
children with massive destruction and even surgical removal of a
hemisphere recover amazingly well without conscious effort.  When you
study these people physiologically, you can see evidence of different
mechanisms of recovery at work.

I hope this settles your mind a bit, and provokes some comment from others.

Eric Wassermann

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