Mayo's Older Americans Normative Studies: Age- and IQ-Adjusted Norms for the Trail-Making Test, the Stroop Test, and MAE Controlled Oral Word Association Test

ABSTRACT

Although normative data sets for standardized neuropsychometric instruments often include adjustments for subject variables, there are reasons to believe that improvements in interpretive accuracy that result from such adjustments are less than optimal. In particular, years of formal education may be less closely related to test performances than is general intellectual functioning. In this second of four reanalyses of results from the Mayo Clinic's Older Americans Normative Studies (MOANS) databases, age-adjusted scores for the Trail-Making Test, the Stroop Color-Word Test, and the MAE Controlled Oral Word Associations Test were found to be more strongly associated with Mayo age-adjusted WAIS-R Full Scale IQ scores (rs = .368 to .495) than with education (rs = .174 to .367) for healthy older examinees between 56 and 99 years of age. For the TMT and the COWAT, but not the Stroop, these associations became stronger as IQ increased (cf. Dodrill, 1997, 1999). Tables of age- and IQ-adjusted percentile equivalents of MOANS age-adjusted TMT, Stroop, and COWAT scores are presented for eleven age ranges and seven IQ ranges.

Notes

The COWAT uses the letters C, F, and L (rather than the letters F, A, and S) as stimuli for three one-minute trials. Although an alternate form of the COWAT (using the letters P, R, and W) is available, the present work did not involve the latter.

Although replication of these findings by multiple labs suggests that we may be moving closer to an understanding of the cognitive processes that underlie the Stroop test, it should be noted that experimental variants of the Stroop task must be used in neuroimaging studies. For this reason, applicability to the particular forms of the Stroop that are used in the clinic may be imperfect.

Note. TMT = Trail-Making Test; COWAT = Controlled Oral Word Association Test.

^a The reader is advised that these age ranges do not coincide with the age ranges or cell sizes that appear in the normative data tables that appear below.

^b “Non-Caucasian” includes African American, Latino, Canadian, and Western European.

Note. Scaled scores and IQ scores are age-adjusted. TMT = Trail-Making Test; COWAT = Controlled Oral Word Association Test; MOANS = Mayo's Older Americans Normative Studies; FSIQ = Full Scale IQ; VIQ = Verbal IQ; PIQ = Performance IQ.

Participants' scaled scores on the COWAT and the Word condition of the Stroop were more closely related to their VIQ scores than to their PIQ scores, and the reverse pattern was noted for their scores on the TMT (Parts A and B) and the Color and Color-Word conditions of the Stroop (data not reported here). In four of six cases, however, test scores were more strongly associated with FSIQ than with either VIQ or PIQ. Consequently, we chose to use FSIQ as the stratification variable for all norms that appear in this paper.

Note. MOANS = Mayo's Older Americans Normative Studies; TMT = Trail-Making Test; COWAT = Controlled Oral Word Association Test; FSIQ = Full Scale IQ; VIQ = Verbal IQ; PIQ = Performance IQ.

^a p < .05.

^b p < .01.

The one exception to this was the observation that the strongest correlations for each test occurred for the lowest IQ score range (<95). This likely reflects the fact that this category included many more possible IQ score values than did the remaining five-point categories. A less pronounced and less consistent pattern was noted for the highest IQ category (>119), presumably for the same reason.

Note. MOANS = Mayo's Older Americans Normative Studies; TMT = Trail-Making Test; COWAT = MAE Controlled Oral Word Association Test; FSIQ = Full Scale IQ; VIQ = Verbal IQ; PIQ = Performance IQ.

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).

^a To use, find table that corresponds to examinee's age, locate appropriate test score and FSIQ column, and determine percentile equivalent of raw score or age-adjusted MOANS scaled score (cf. TCN, 10, 262–278).