Direct and indirect effects of demographic, medical, and psychological variables on neuropsychological performance in normal geriatric persons: a structural equation model.

The direct and indirect effects of demographic, medical, and psychological variables on neuropsychological performance in elderly individuals were examined using a LISREL structural equation model. One-hundred fifty-six geriatric subjects were individually administered a comprehensive neuropsychological battery, an extensive medical history and demographics questionnaire, and the Neuropsychology Behavior and Affect Profile (a psychological assessment instrument). The model assessed the effects of five independent latent variables (medical history, psychological functioning, global mental status, education, and gender-related functioning) on two dependent latent variables (nonverbal and verbal neuropsychological functioning). The best fitting model revealed that three latent variables (medical history, global mental status, and gender-related functioning) had direct effects on neuropsychological functioning and that all five independent variables exhibited indirect effects. These findings suggest that the influence of demographic variables on neuropsychological functioning for geriatric persons is complex and that certain variables should not be interpreted independently of each other due to their significant moderating influences.

Alternate forms of the Auditory-Verbal Learning Test: issues of test comparability, longitudinal reliability, and moderating demographic variables.

The present investigation examines the alternate-form and longitudinal reliability of two versions of the Auditory-Verbal Learning Test (AVLT) on a large, multiregional, healthy male sample. Subjects included 2,059 bisexual and homosexual HIV-seronegative males recruited from the Multicenter AIDS Cohort Study from centers in Baltimore, Chicago, Los Angeles, and Pittsburgh. The findings revealed no significant differences between forms upon initial or 1-year longitudinal administration, supporting the equivalence of the two versions. However, significant practice effects were noted longitudinally, arguing for the need of appropriate retest normative data. Furthermore, as age, ethnicity, and education were found to significantly affect test performance, it is recommended that normative data be interpreted according to these variables. In addition to providing normative and longitudinal data, this investigation presents information concerning the use and limitations of the alternate forms of the AVLT.

Frontal lobe functioning in geriatric and non-geriatric samples: an argument for multimodal analyses.

The present investigation examines specific aspects of frontal functioning across geriatric and nongeriatric cohorts. Subjects included 193 nongeriatric male pilots (mean age: 48.29 (SD = 6.79); mean education: 15.93 years (SD = 1.86)), and 68 geriatric males and females (mean age: 78.38 (SD = 5.07); mean education: 13.68 (SD = 2.53)). The results of a series of general linear model multivariate one-way analyses revealed poorer performance on frontal measures in the geriatric sample, although no differences were noted between the male and female samples. In contrast, variable interrelations, as assessed by a parametric statistic of betweengroup factor similarity, indicated a noteworthy similarity of factors between the geriatric and nongeriatric groups, and dissimilarities between the factor structures for males and geriatric females. These findings not only support the presence of age-related differences in frontal performance for the domains tested, they suggest the need to examine frontal functioning by multiple methods, as differences in frontal functioning may exist between groups that are undetected by analyses based on intergroup score differences or predictor-criterion correlations alone

The relation between loudness and intensity difference limens for tones in quiet and noise backgrounds.

Recent studies of the relation between loudness and intensity difference limens (DLs) suggest that, if two tones of the same frequency are equally loud, they will have equal relative DLs [R. S. Schlauch and C.C. Wier, J. Speech Hear. Res. 30, 13-20 (1987); J.J. Zwislocki and H.N. Jordan, J. Acoust. Soc. Am. 79, 772-780 (1986)]. To test this hypothesis, loudness matches and intensity DLs for a 1000-Hz pure tone in quiet and in a 40-dB SPL spectrum level broadband noise were obtained for four subjects with normal hearing. The DLs were obtained in both gated- and continuous-pedestal conditions. Contrary to previous reports, equally loud tones do not yield equal relative DLs at several midintensities in the gated condition and at many intensities in the continuous condition. While the equal-loudness, equal-relative-DL hypothesis is not supported by the data, the relation between loudness and intensity discrimination appears to be well described by a model reported by Houtsma et al. [J. Acoust. Soc. Am. 68, 807-813 (1980)].