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Mark Sherer, PhD, ABPP-Cn, The Institute for Rehabilitation Research at

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Sherer, M. (2004). The Confusion Assessment Protocol. The Center for Outcome Measurement in Brain Injury.
combi/cap ( accessed ).





Introduction to the Confusion Assessment Protocol

The Confusion Assessment Protocol (CAP) is a combination of objective measures of orientation and cognition and clinician ratings of other symptoms of early confusion after traumatic brain injury (TBI). The CAP was developed by Mark Sherer, Risa Nakase-Thompson, and Stuart A. Yablon for use in investigations of early recovery from TBI. This measure is still in an early phase of development with several investigations still ongoing.

Patients in early recovery from TBI frequently are acutely confused. The term Post-traumatic Amnesia (PTA) has been used to describe this state. However, commonly used measures of PTA primarily assess orientation and memory and fail to assess other symptoms of confusion. More recently, Stuss and colleagues (Stuss et al., 1999) proposed the term Post-traumatic Confusional State (PCS) to describe this early period of recovery after TBI. Stuss and colleagues noted the similarity of this period of recovery to delirium. These researchers recommended a focus on assessment of attentional skills in confused patients.

The CAP was developed to assess a broad range of symptoms of PCS. In constructing the CAP, scales previously used to assess PTA and delirium were administered to a sample of patients with TBI who were in inpatient rehabilitation. These scales included the Galveston Orientation and Amnesia Test (GOAT; Levin, O’Donnell, & Grossman, 1979), the Agitated Behavior Scale (ABS; Corrigan, 1989), the Delirium Rating Scale – Revised (DRS-R; Trzepacz, Mittal, Torres, Kanary, Norton, & Jimerson, 2001), the Cognitive Test for Delirium (CTD; Hart, Levenson, Sessler, Best, Schwartz, & Rutherford, 1996) and the Toronto Test of Acute Recovery from TBI (TOTART; Stuss et al., 1999). Patient responses to each item of each scale were reviewed by 2 clinicians. Items were retained if they differentiated patients meeting DSM-IV criteria for delirium from those not meeting DSM-IV criteria and if, in the judgment of the clinicians, they provided clinically significant information. Items were deleted if they were redundant or did not discriminate patients who met DSM-IV delirium criteria from those who did not. Some items were modified. Based on this analysis, 7 key symptoms of PCS were identified. These are: (1) disorientation, (2) cognitive impairment, (3) restlessness, (4) fluctuation in presentation, (5) nighttime sleep disturbance, (6) decreased daytime level of arousal, and (7) psychotic-type symptoms. CAP items assess all 7 of these symptoms. Note that all patients in our sample showed some degree of cognitive impairment. The scoring criteria for the cognitive items were set to identify those patients with levels of cognitive impairment that could be seen in patients with delirium.

As noted above, the CAP was developed as a research tool. While the symptoms measured have clear clinical relevance, the clinical utility of the CAP remains to be demonstrated.

This information regarding the CAP was provided by Mark Sherer, Ph.D., ABPP-Cn of The Institute for Rehabilitation Research. Please contact Mark Sherer, PhD, ABPP-Cn, at for more information.

If you find the information in the COMBI useful, please mention it when citing sources of information. The information on the Confusion Assessment Protocol may be cited as:

Sherer, M. (2004). The Confusion Assessment Protocol. The Center for Outcome Measurement in Brain Injury. ( accessed ).



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