Brain injuries and mood changes
john at faraway.com
Tue Jul 15 23:18:10 EST 2003
A vexed question. Very hard to know why these changes occur but even in some
cases of mild traumatic brain injury there is emotive changes. One study I
read showed changes in cortisol levels (stress hormone) in TBI patients,
irrespective of injury location. Primarily the cortisol levels were raised
relative to controls early in the morning. I hypothesis I read suggested
that kinetics of brain injury may induce injury to nerves projecting to the
hypothalamus (PVN) which may upset the dynamics of this stress regulation
centre. Other studies suggest this may be possible, diffuse axonal injury is
a common but until recently under recognised consequence of TBI, you need
specific imaging techniques to identify this type of injury and a recent
study suggested the extent of DAI is a key indicator of the severity of TBI.
One angle that interests me in this regard is that the PVN lies in close
proximity to the ventricles, perhaps the kinetic force has a different
effect when it encounters the ventricles, may be even generates a wave
motion in the fluid which impacts on the ventricle walls and so damaging
nearby neural tissue. This is highly speculative though and I don't know of
any studies which point to this as a possible cause.
There is also some suggestion that dopamine and\or norepinephrine activity
is affected by TBI.
Another aspect that is worth considering is that the cognitive consequences
of TBI impact on the person's ability to organise their thoughts and be who
they previously were, hence stress ensues because the individual must now
cope with the many new challenges that confront them as a result of the
changes to their cognition. This idea has some merit in the sense that even
in mild injury or injury remote from areas involved in mediating emotions
and the stress response the same symptoms will appear.
Another approach is to consider that because of injury the brain undergoes a
systemic change in its immunological state. I have seen references
indicating that even many months (and years) after TBI there is ongoing
evidence of inflammation and\or tissue damage occurring. This seems
particularly true of damage to the basal ganglia, dopamine cell loss can
continue long after the injury (years) and this very much suggests an
ongoing process of deterioration, albeit at very low levels.
The jury very much remains undecided about the causes of these changes in
people with TBI. What is more important is ways to help patients who have
experienced TBI and are suffering from depression etc as a result. Most of
the research is focussed on this aspect but of course knowing why it is
helping would help considerably. One issue that is important here that
during the recovery phase the patient needs good social support. How people
close to the patient respond to them and their difficulties post TBI may
have significant consequences in relation to how the patient comes to terms
with their injury and its consequences. Nutritional status at the time of
injury can also impact on the extent of injury, it is important that people
with TBI pay very close attention to their diet and should be subject to a
regime of rehabilitation that maximises recovery potential. Unfortunately
most perceive the critical period of TBI as the first few weeks, I suggest
that we should extend that to many months for some people.
If the appropriate tools were available to me I would be looking closely at
the kinetic effects of TBI, my belief is that widescale microstructural
changes (particularly in relation to dopaminergic synapses) occur and that
the ability of the brain to compensate for this damage will be contingent on
the ongoing social support (thereby reducing stress) and good diet are
important factors in determining recovery from TBI.
johnYYYcoe at tpg.com.au
remove YYY in reply
"Nacho" <marquesdesadeNOSPAM at chile.com> wrote in message
news:3f1435ec$1 at news...
> There are some mood changes that can be seen on brain injuries, as
> depression, anxiety, irritable, or restless.
> What can be the reason of that change? Physiologically, what areas are
> I'm reffering to the general brain injury, as a TBI, not to specific
> injuries related to emotions.
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