Contact Jennifer
Bogner, Ph.D.
Ohio Regional TBI Model System, at
Citation Bogner, J. (2000). The
Agitated Behavior Scale. The Center for Outcome Measurement
in Brain Injury. http://www.tbims.org/
combi/coglog ( accessed
).
ABS
Syllabus
Introduction
Agitation
during the acute phase of recovery from brain injury is often observed,
usually treated, but rarely measured. Denny-Brown (1945) first observed
that excited and restless behavior may be natural sequela of recovery
from traumatic brain injury. The term "agitation" was used to define
Level IV of the Rancho Los Amigos Levels of Cognitive Functioning
Scale. This "confused-agitated" stage was described as a time when
a patient is in a heightened state of activity and has diminished
capability for processing new information and responding to events
in the environment (Malkmus, Booth & Kodimer, 1980). Levin and
Grossman (1978) found that approximately one-third of patients with
closed head injuries on a neurosurgery service experienced agitation
marked by disinhibited movement, restlessness, thrashing, and aggressiveness.
Brooke, Questad, Patterson, and Bashak (1992) conducted a prospective
study of 100 patients with closed head injuries admitted for acute
hospitalization and found 11% showed marked aggression and 35% restlessness.
Reyes, Bhattacharyya and Heller (1981) studied patients admitted
to an acute rehabilitation unit and found that more than half exhibited
restless and agitated behavior. At Ohio State University (Bogner
& Corrigan, 1995), data compiled from a prospective sample of
100 consecutive admissions to the rehabilitation unit indicated
that 42% of the sample exhibited agitated behavior.
Because
of its disruption of therapeutic goals, significant agitation during
rehabilitation has to be addressed, and various behavioral, environmental
and pharmacological interventions have been used. A survey conducted
by Herbel, Schermerhorn and Howard (1990) found that facilities
treating agitated patients use a variety of techniques, with most
having options for one-to-one supervision, behavior modification,
physical restraints, environmental modifications and medication.
With regard to the latter, the research literature is sprinkled
with case studies of the effectiveness of various medications in
improving agitation. While there is not clinical consensus about
which medications are effective in what circumstances (Fugate, Spacey,
& Kresty, 1997), there is an understanding that those pharmacologic
interventions which reduce agitation through sedation can delay,
if not prevent, patients' cognitive and functional improvement during
the acute phase of recovery (Mysiw & Sandel, 1997). Empirical
support for this contention was provided by Corrigan and Mysiw (1988)
who found that improvement in cognition was a prerequisite to improved
agitation for patients who demonstrated both.
Despite
the documented frequency of agitation in patients with traumatic
brain injuries, as well as the need to treat this condition, until
recently there has not been an objective measure of agitation. The
Agitated Behavior Scale (ABS; Corrigan, 1989) was developed to allow
objective assessment of this behavior, particularly serial assessments
for the evaluation of interventions to reduce agitation. To construct
the ABS, a preliminary pool of 39 items was generated from review
of the literature and use of Kelly's (1955) construct elicitation
methodology with interdisciplinary staff experienced in brain injury
rehabilitation. In a pilot study, 14 items were selected from this
pool based on degree of inter-rater reliability, differentiation
of agitation, frequency of occurrence, and representation of factors
present in the original item pool. The final 14-item scale was then
validated on an independent sample and was found to have appropriate
levels of inter-rater reliability, internal consistency and concurrent
validity (Corrigan, 1989).
Subsequent
studies have provided support for the construct validity of the
ABS (Corrigan & Mysiw, 1988; Corrigan, Mysiw, Gribble &
Chock, 1992; Corrigan, Bogner, & Tabloski, 1996; Novack &
Penrod, 1993; Tabloski, McKinnon-Howe, & Remington, 1995). Corrigan
and Bogner (1994) reported additional evidence of construct validity
via delineation of the factor structure of the ABS. In their sample
of 212 patients with recently acquired brain injury who exhibited
agitation during acute rehabilitation, confirmatory factor analyses
revealed that agitation is represented by one general construct
with three underlying, correlated factors: Aggression, Disinhibition,
and Lability. They concluded that the Total Score remains the best
measure of agitation, but subscale scores may provide important
additional clinical and research data.
Based
on studies investigating the construct validity of the Agitated
Behavior Scale, as well findings in the research literature regarding
traumatic brain injury and other conditions which have agitation
as a potential sequela, the following definition of agitation has
been proposed:
Agitation
is an excess of one or more behaviors that occurs during an altered
state of consciousness (Bogner & Corrigan, 1995).
This
definition emphasizes the importance of "excessiveness" over the
type of behavior manifested. "Excessiveness" has been operationalized
as the degree to which the behavior interferes with functional activities
and the extent to which the behavior can be inhibited. As suggested
by the factor analysis, no one type of behavior defines agitation,
though some component behaviors may be more dominant at times. The
definition also requires that the behavior occur during an altered
state of consciousness which, for traumatic brain injury, includes
the diminished arousal present from time of injury through the clearing
of post-traumatic amnesia. This definition is reflected in the criteria
used to rate the behaviors which comprise the ABS.
Administration
A rating
of "1" is ascribed when the behavior in the item is not present.
Ratings of "2," "3," and "4" indicate the behavior is present and
differentiate the degree or severity. Degree can be a function of
either the frequency with which the behavior occurs or the intensity
of individual occurrences.
Raters
should be instructed that the basis for establishing the degree
is the extent to which the occurrence of the behavior described
in the item interferes with functional behavior that would be appropriate
to the situation:
We
suggest a rating of "2" or "slight" be ascribed when the behavior
is present but does not prevent the conduct of other, contextually
appropriate behavior. Patients may redirect themselves spontaneously
or the continuation of the agitated behavior does not preclude
the conduct of the appropriate behavior.
A
rating of "3" or "moderate" indicates the individual may need
to be redirected from an agitated to an appropriate behavior,
but is able to benefit from such cueing.
A
rating of "4" or "extreme" is ascribed when the individual is
not able to engage in appropriate behavior due to the interference
of the agitated behavior, even when external cueing or redirection
is provided.
Scoring
The
Total Score is calculated by adding the ratings (from one to four)
on each of the fourteen items. Raters are instructed to leave no
blanks; but, if a blank is left, the average rating for the other
fourteen items should be inserted such that the Total Score reflects
the appropriate possible range of values. The Total Score is the
best overall measure of the course of agitation (Corrigan, 1989;
Corrigan & Bogner, 1994).
Subscale
scores are calculated by adding ratings from the component items:
Disinhibition
is the sum of items 1, 2, 3, 6, 7, 8, 9 and 10.
Aggression
is the sum of items 3, 4, 5 and 14. (It is not an error that Item
#3 is in both scores.)
Lability
is the sum of items 11, 12 and 13.
In
order to allow subscale scores to be compared to each other and
to the Total Score, it is recommended that an average item score
for each factor be calculated and multiplied by fourteen. This procedure
provides subscale scores with the same range as each other and the
Total Score, which is useful for graphic presentation.