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.