A Neuropsychiatric Classification of CHIT: a new
terminology
We have chosen to modify the definition
proposed by the Interdisciplinary Special Interest
Group of the American Congress of Rehabilitative Medicine
(Kay, et al, 1993). Proposed instead is the use of
the term closed head injury of transient kind
(CHIT) to describe a traumatic induced psychophysiologic
event that occurs to the head which produces initially
little or no unconsciousness, limited retrograde and
anterograde amnesia and alteration of consciousness
that does not last longer than a day. We feel the
term "closed" head injury should
be used because injuries involving skull fractures
and open exposure of the brain have their own special
characteristics such as infection, vascular phenomena
and focal disease. We prefer terms like "head"
to "brain" because this way psychiatric
sequelae are not necessarily implied to have a definite
organic base. We understand that there is an observable
and diagnosable cluster of physical, cognitive and
psychological symptoms that is associated with CHIT
and is most usefully defined as posttraumatic CHIT
syndrome (PTCHITS). Because injury usually
implies "traumatic" we see redundancy in
using terms like traumatic (brain or head) injury:
injury will suffice. Finally, and most important,
we feel it is important to be non-prejudicial at the
outset hence the term transient. CHITs are
often reported to be of mild severity but the
mildness is not invariably so and the trauma may lead
to significant sequelae. Conversely, many so-called
"mild" injuries are more severe because
of the lack of available compensation by the brain.
We believe terms like "mild" (or for that
matter "minor"), " moderate",
"severe" and "profound" should
be confined to severity of outcome and not assumed
on the basis of initial duration of unconsciousness.
Consequently, we do not like the term "brief"
preferring "transient. Although the two
are similar, brief is more unidimensional in the context
of implying some unconsciousness and not commenting
on duration of clouding or altered consciousness.
"Transient" implies an injury but unconsciousness
may not be proven and it takes this into account.
On the one hand, such an injury can occur without
distinguishable disruption of brain function and yet
still be considered as a traumatic event. Some call
this post-traumatic syndrome. Alternatively,
such an injury can result in a disruption of brain
function and thus be considered transient traumatic
brain injury - some call this post-concussional
syndrome. Additionally, Kurt Goldsteins dichotomy
of "pathogenetic" changes based on the actual
injury and "pathoplastic" compensations
by other areas of the brain or by psychological adaptation
introduces a situation of health as opposed to disease
into the equation (Neppe and Tucker, 1988A). Consequently,
we prefer "transient" in CHIT which we contrast
with "prolonged" and the term CHIP -
closed head injury of prolonged type in which
there is clinically significant retrograde or anterograde
amnesia, extended confusion or clouded consciousness
over more than a day, or prolonged unconsciousness
of more than a day. Transient implies an apparent
blow to the head with no, momentary or very short
consciousness impairments, with the amnesia and confusion
range from momentary to up to a day. In this regard,
CHIPs can always be further subdefined descriptively:
a CHIP with two days coma as opposed to CHIPs with
half hour unconsciousness but two weeks confusion.
Seen within the CHIT syndrome are three
subsyndromes which can occur together: postconcussive
, posttraumatic and focal residual. Assumed by definition
is that with the postconcussive subsyndrome, the brain
has been concussed and there is a predominant physiologic
basis for primary symptoms and secondary psychologic
processes that contribute to the manifestation of
symptom patterns. With the posttraumatic subsyndrome,
there is a predominant feature of acute or chronic
post traumatic stress that represents the primary
cluster of symptoms. With both the postconcussive
and posttraumatic subsyndromes are typically an overlay
of pain syndrome that may have physiologic and/or
psychologic factors that affect the pain behavior.
The focal residual syndrome involves focal dysfunction
such as the development of episodic or paroxysmal
atypical spells or seizure type phenomena. These usually
impact on the cerebral cortex or manifest as a pain
syndrome.