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Abstracts
Clin Neuropsychol 2000 Aug;14(3):325-40
Limited accuracy of premorbid intelligence estimators:
a demonstration of regression to the mean.
Basso MR, Bornstein RA, Roper BL, McCoy VL.
Department of Psychology, University of Tulsa, OK 74104-3189,
USA. michael-basso@utulsa.edu
Regression-based premorbid intelligence estimators have
been devised by Barona, Reynolds, and Chastain (1984), Barona
and Chastain (1986), Hamsher (1984), Krull, Scott, and Sherer
(1995; the Oklahoma Premorbid Intelligence Estimate: OPIE),
and Vanderploeg, Schinka, and Axelrod (1996; BEST-3 approach),
but little is known of their relative accuracy, particularly
in outer ranges of intellectual ability (e.g., below-average,
superior, etc.). Towards this end, the Wechsler Adult Intelligence
Scale-Revised (WAIS-R) was administered to 150 neurologically
normal adults, and estimated VIQ, PIQ, and FSIQ scores were
computed according to each regression method. Results showed
that methods based solely on demographic factors were most
susceptible to meanward regression, rendering them poor
estimators of IQ scores in outer ranges. Although the OPIE
and BEST-3 performed somewhat better, their accuracy remained
relatively weak. The findings suggest that regression-based
estimates of premorbid IQ are very susceptible to error,
particularly in outer ranges of intellectual function.
J Clin Exp Neuropsychol
1999 Jun;21(3):368-74
WAIS-R prediction equations in patients with traumatic
brain injury.
Axelrod BN, Vanderploeg RD, Rawlings DB.
John D. Dingell Department of Veterans Affairs Medical Center,
Detroit, MI, USA. axelrod.bradley@forum.va.gov
Arithmetic algorithms for predicting premorbid Full Scale
IQ were evaluated in a sample of 125 brain injured adults
who had been evaluated within two months of their injury,
and then again one year later. FSIQ at post-test was used
as the criterion variable. The prediction equation, based
on demographic information only (Barona, Chastain, & Reynolds,
1984), proved to be a modest predictor of premorbid FSIQ.
The BEST-3 (Vanderploeg & Schinka, 1995), a prediction equation
that incorporates demographic information and performance
data, was sensitive to the severity of the brain injury.
Subsequent analyses found the BEST-3 to be a better predictor
of recovery of function than it was an estimate of premorbid
functioning. This study demonstrates the need for flexibility
in the interpretation of results, as what was thought to
be a prediction equation for premorbid functioning was better
viewed as an estimate of recovery.
J Clin Psychol 1997 Nov;53(7):647-56
Estimating premorbid WAIS-R intelligence in the elderly:
an extension and cross validation of new regression equations.
Paolo AM, Ryan JJ, Troster AI.
University of Kansas Medical Center, Kansas City 66160,
USA.
Recently developed equations that combine WAIS-R subtests
and demographic information to estimate premorbid intelligence
were evaluated in persons 75 years and older. The equations
underestimated the obtained IQs of elderly persons. Therefore,
new equations were developed using the old age WAIS-R standardization
sample. The new equations cross-validated well and demonstrated
adequate ability to detect possible intellectual deterioration
in a brain damaged sample. The demographic formulas of Barona,
Reynolds, and Chastain worked as well as the new equations
in suggesting possible deterioration in a sample of elderly
persons with chronic and diffuse cognitive impairment.
J Clin Psychol 1996 May;52(3):335-43
Utility of the Barona demographic equations to estimate
premorbid intelligence: information from the WAIS-R standardization
sample.
Paolo AM, Ryan JJ, Troster AI, Hilmer CD.
Department of Neurology, University of Kansas Medical Center,
Kansas City 66160-7314, USA.
The WAIS-R (Wechsler, 1981) and elderly WAIS-R standardization
samples (Ryan, Paolo, & Brungardt, 1990) were combined to
evaluate the utility of the Barona demographic regression
equations (Barona, Reynolds, & Chastain, 1984) to estimate
premorbid intelligence. The equations underestimated ability
for persons with IQs less than 80 and overestimated ability
of subjects with IQs greater than 119. The equations also
overestimated the IQs of 247 persons with confirmed brain
dysfunction. Because this overestimation occurred for impaired
persons with IQs less than 90, it is difficult to determine
whether the difference reflects true intellectual deterioration
or statistical artifact. Abnormal cut-off scores at the
10% and 5% levels are provided to allow clinicians to detect
abnormal discrepancies between the estimated and obtained
IQs.
The Clinical Neuropsychologists
2000 14(2):181-186
PPVT-R as an Estimate of Premorbid Intelligence in Older
Adults.
Snitz BA, Bieliauskas LA, Crossland
A, Basso MR, Roper B.
The Peabody Picture Vocabulary
Test-Revised (PPVT-R) was examined as an estimate of premorbid
intelligence in a clinical sample of elderly patients (N
= 150) undergoing clinical neuropsychological evaluation.
PPVT-R standard scores were compared across grossly cognitively
intact, mildly/moderately and severely impaired groups of
patients, and compared to a short form of the Wechsler Adult
Intelligence Scale-Revised (WAIS-R) and the Barona regression
equation. Results indicate that, while the PPVT-R is vulnerable
to increasing levels of cognitive impairment among patients
with fewer years of education, the PPVT-R is stable across
mild to moderate levels of impairment for patients with
greater than 12 years of education. In a sub-sample of grossly
cognitively intact patients (n = 91), the PPVT-R standard
score correlated significantly with estimated WAIS-R FSIQ
(r = .61). Compared to the Barona equation, the PPVT-R was
less likely to over-estimate WAIS-R FSIQ in the grossly
cognitively intact patients. These data suggest the PPVT-R
to be a useful estimate of premorbid ability for patients
with a greater than high-school education.
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