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
means and standard deviations for the Total Score and subscale scores
are based on samples of persons with traumatic brain injury treated
during the acute phases of recovery on an inpatient, rehabilitation
unit. A prospective sample of all patients with brain injuries,
regardless whether they were demonstrating agitation, revealed an
overall mean ABS score of 21.01 and standard deviation of 7.35 for
day shift nursing observations (Corrigan, 1989). For clinical purposes,
we consider any scores (Total or converted subscale) 21 or below
to be within normal limits; from 22 through 28 to indicate mild
occurrence; 29 through 35 to indicate moderate; and more than 35
to be severe.
norms based on a broader sampling of patients from other institutions
will be desirable, the ABS remains quite usable for ipsative comparisons
of the same individual from shift to shift, therapy to therapy,
and/or day to day.
initial validation studies (Corrigan, 1989) showed correlations
between ratings conducted on the same day exceeded .70 for the Total
score (subscale scores were not available at that time). Inter-rater
reliability was recently re-examined (Bogner, et al, in press) due
to the instrument's increased use with different populations, rated
by individuals from various disciplines, based on a variety of observation
a sample of persons receiving acute rehabilitation for acquired
brain injury, research assistants (psychology interns and a rehabilitation
nurse) rated behavior based on 10-minute observation periods. The
research assistants' ratings yielded a correlation coefficient for
the Total score of .92. The correlation coefficients for the factors
Disinhibition, Aggression, and Lability were .90, .91, and .73,
respectively. The reliability of the Lability score is likely effected
by the small number of items used in its calculation. When comparisons
were made between the ratings made of the research assistants based
on 10 minute observation periods and the ratings made by nurses
based on an 8-hour shift, the correlation coefficients for the Total
and subscale scores were much lower (.36 to .60). This difference
reflects the fact that when ratings are made under different conditions,
in different time intervals, by different types of raters, what
is being measured is also different. Agitation has been known to
change in intensity throughout the day, and in response to the regulation
of stimulation. When serial monitoring is the goal, it is important
that comparisons be made under comparable conditions.
reliability was also examined with a sample of individuals residing
in a long-term care facility whose primary diagnosis was dementia.
The ratings were again made by research assistants based on 10-minute
observation periods. The correlation coefficient for the Total score
was .91, while the coefficients for the factor scores were .87 for
Disinhibition, .89 for Aggression, and .86 for Lability.
of the internal consistency of the scale found Cronbach's alphas
ranging from .83 to .92 in the original validation study (Corrigan,
1989). With the two samples examined by Bogner et al (in press),
Cronbach's alphas ranged from .74 to .92. The relatively high internal
consistency of the scale suggests that agitation, as measured by
the ABS, is a unitary construct, with three facets being individually
prominent at times.
original development of the ABS demonstrated the content validity
of items and concurrent validity of the Total Score. Subsequent
studies have shown the ABS to be predictive of change in cognitive
status (Corrigan & Mysiw, 1988) and able to differentiate confusion
and inattention (Corrigan & Mysiw, 1988; Corrigan et al., 1992).
Construct validity has been further substantiated by the identification
of underlying factors (Corrigan & Bogner, 1994). The Total Score
and three underlying subscales have proven stable over multiple
samples (Corrigan & Bogner, 1994).