Linda D. Nelson

The Dysfunctional Attitude Scale : how well can it measure depressive thinking ?

The Dysfunctional Attitude Scale (DAS) was designed to measure patterns of maladaptive thinking held by depressed individuals. Despite its wide use as a research and clinical tool, only a few studies to date were designed to examine its psychometric properties in a clinically depressed population. Moreover, problems of low sample size and limited tests of validity call these findings into question. The present study was designed to examine psychometric properties of the DAS in clinically depressed inpatients and in nondepressed clinical controls. Intertest correlations between the DAS parallel forms and between each form with total test scores ranged from r=.84 to r=.97. Intratest stability coefficients were r=.88 to r=.97. Support for the DAS as a valid measure of dysfunctional cognitions in depressed patients was also indicated. Of those scoring high on the DAS, 73% received an independent RDC diagnosis of clinical depression, while only 36% of those receiving low DAS scores were so diagnosed.

Positron Emission Tomography of Brain β-Amyloid and Tau Levels in Adults With Down Syndrome

OBJECTIVES To determine the neuropathological load in the living brain of nondemented adults with Down syndrome using positron emission tomography with 2-(1-{6-[(2-fluorine 18-labeled fluoroethyl)methylamino]-2-napthyl}ethylidene) malononitrile ([(18)F]FDDNP) and to assess the influence of age and cognitive and behavioral functioning. For reference, [(18)F]FDDNP binding values and patterns were compared with those from patients with Alzheimer disease and cognitively intact control participants. DESIGN Cross-sectional clinical study. PARTICIPANTS Volunteer sample of 19 persons with Down syndrome without dementia (mean age, 36.7 years), 10 patients with Alzheimer disease (mean age, 66.5 years), and 10 controls (mean age, 43.8 years). MAIN OUTCOME MEASURES Binding of [(18)F]FDDNP in brain regions of interest, including the parietal, medial temporal, lateral temporal, and frontal lobes and posterior cingulate gyrus, and the average of all regions (global binding). RESULTS The [(18)F]FDDNP binding values were higher in all brain regions in the Down syndrome group than in controls. Compared with the Alzheimer disease group, the Down syndrome group had higher [(18)F]FDDNP binding values in the parietal and frontal regions, whereas binding levels in other regions were comparable. Within the Down syndrome group, age correlated with [(18)F]FDDNP binding values in all regions except the posterior cingulate, and several measures of behavioral dysfunction showed positive correlations with global, frontal, parietal, and posterior cingulate [(18)F]FDDNP binding. CONCLUSIONS Consistent with neuropathological findings from postmortem studies, [(18)F]FDDNP positron emission tomography shows high binding levels in Down syndrome comparable to Alzheimer disease and greater levels than in members of a control group. The positive associations between [(18)F]FDDNP binding levels and age as well as behavioral dysfunction in Down syndrome are consistent with the age-related progression of Alzheimer-type neuropathological findings in this population.

Learning and memory as a function of age in Down syndrome : A study using animal-based tasks

Individuals with Down syndrome (DS) are at a high risk for developing Alzheimer disease (AD) after the age 40; however, low levels of intellectual functioning, coupled with impaired language ability, confound the detection of AD. Comparative neuropsychological tests developed in animal models of aging and cognition do not require intact language function and can be useful for detecting changes in cognition. Experimental paradigms used to detect age-dependent cognitive deficits in animal models were applied in the present study to measure cognitive function in a group of 20 adults with DS ranging in age from 22 to 58 years. Object discrimination, reversal learning, and spatial and object memory were administered using a modified Wisconsin General Testing Apparatus and reinforcement (penny rewards). When considering age as the only clinical variable to parallel the animal studies, age was significantly correlated with performance on object memory and marginally related to performance on reversal learning and spatial memory. However, when evaluating multiple clinical variables including age, a measure of intellectual ability (FSIQ), scores on the Dementia Questionnaire for Persons with Mental Retardation (DMR), and gender using regression analysis, scores on the DMR were the best predictors of errors of reversal learning, whereas FSIQ was the best predictor of performance on object memory. These results suggest that while age may be related to performance on learning and memory tasks, other clinical variables may be stronger predictors of performance in adults with DS. These changes may reflect prefrontal and medial temporal lobe dysfunction that is associated with the development of AD pathology in DS.

Re-examining handedness in schizophrenia: now you see it--now you don't.

The present study was designed to examine patterns of handedness across tasks (i.e., those requiring less vs. greater skill) and over time (initially and 1 month later) in 72 schizophrenic patients and 105 normal controls. Two important methodologic advances were introduced: (1) two handedness tasks, varying in skill level (simple vs. complex); and (2) the addition of a retest on both tasks, 1 month later. Results show a higher incidence (43%) of mixed handedness in the schizophrenic sample than in normal controls (14.3%) on tasks requiring less precision in performance. Similar results were obtained when schizophrenic patients were retested 1 month later, RI = .88. When the more demanding set of tasks was presented, the frequency of mixed handed schizophrenics dropped by 50% at initial testing. Despite these findings, there was no evidence for stability of change over time. For example, each of the most extreme shifters at Time 1 was fully lateralized 1 month later.

Emotional sequelae of stroke: A longitudinal perspective

This study investigated emotional change following stroke at acute (2-week), 2-month, and 6-month time intervals. Five dimensions of emotional functioning were examined in a sample of 19 stroke subjects: indifference, inappropriateness, depression, mania, and pragnosia (a defect in the pragmatics of social communicative style). Results showed that, at the 2-month point, differential recovery rates become apparent depending on hemispheric side of the stroke lesion. Increased indifference, inappropriateness, and depression appear to account for these results and suggest a slower rate of recovery on these variables in the left hemisphere group (LH n = 9) compared to the right (RH n = 10). Results further indicate that, at the 6-month point, emotional functioning in RH subjects appears to worsen. In contrast, emotional recovery in LH subjects seems to stabilize at this time. Clinical implications of these findings in terms of type and timing of intervention are discussed.

Personality Change in Head Trauma: A Validity Study of the Neuropsychology Behavior and Affect Profile

This study represents the first attempt to cross validate and report on the Neuropsychology Behavior and Affect Profile (NBAP) using closed head injury (CHI) participants. The NBAP is designed to measure emotional functioning before and following a brain event. Two CHI samples, differing primarily by method of ascertainment, were compared to a group of normal controls. Results provided support for concurrent and predictive validity of the NBAP across both CHI samples. Significantly higher levels of postinjury emotional functioning in clinic-referred CHI patients compared to CHI individuals not seeking treatment (strictly research participants) was demonstrated. A surprising finding was that pre-injury emotional levels of clinic-referred subjects were rated as less severe than that of controls. Based on this finding, the possibility of a gradient effect was discussed in which raters appeared to place selectively greater weight on current condition, while simultaneously making premorbid levels less severe than they really were. Results were discussed in the context of study limitations and directions for further research.

Re-examining threats to the reliability and validity of putative brain-behavior relationships: New guidelines for assessing the effect of patients lost to follow-up

It often happens in behavioral and biomedical research that subjects in prospective, multiple assessment investigations, including clinical trials, are lost to follow-up evaluations. The purpose of this report is to outline a model that will enable the investigators to determine the extent to which results based upon the maintained cohort can be generalized to the attrited cohort, or those subjects lost to follow-up. While our proposed model derives from a specific application pertaining to changes in personality and affect behaviors following left and right hemisphere stroke, it should apply, with appropriate study-specific modifications, to a wide range of follow-up research designs in neuropsychology, behavioral science more generally, and other areas of biomedical research.

Cross-validiation of the Neuropsychology Behavior and Affect Profile in stroke patients.

Internal stability and discriminant validity of the Neuropsychology Behavior and Affect Profile (L. Nelson et al., 1989) were examined in samples of 70 stroke patients and 88 elderly controls. The test is designed to yield indices of premorbid (before-item subset) and present (now-item subset) levels of emotional functioning in each of five scales. With coefficient alphas ranging from.76 to .87, results indicated moderate to high internal stability. The test was also able to reliably distinguish between the criterion stroke sample (n = 42) and a matched group of elderly controls in terms of present levels of emotional functioning (2 weeks poststroke). When discriminant validity was examined in terms of premorbid emotional status (before-item subset), group differences were unexpectedly obtained

Validity of the MMPI depression scale for outpatients

The Minnesota Multiphasic Personality Inventory Depression scale (Scale D) is used widely by clinicians and researchers, yet evidence suggests that this scale may not represent a valid measure of depression. It has been demonstrated among inpatients, for example, that D scores (vs. total scale) represent truer measures of depression. The present study was designed to examine special properties of D using patients (N=87) with milder forms of maladjustment (outpatients)

Development and validation of the Neuropsychology Behavior and Affect Profile.

This series of 4 studies describes the psychometric properties of the Neuropsychology Behavior and Affect Profile, which consists of 5 peer-rated scales (106 items) designed to measure personality change in brain-impaired individuals. Study 1 pertains to item derivation. Study 2 used relatives of 61 Ss identified as demented to determine the tests internal consistency. Results showed moderate levels of internal consistency across the 5 scales, with slightly higher coefficients (.6S-.82) obtained for present (vs. premorbid) emotional status. High test-retest reliability was demonstrated in Study 3 (intraclass correlation coefficients ranged from .92 to .99). Study 4 established discriminant validity; the instrument differentiated 61 demented Ss from 88 normal elderly controls on the basis of present behavioral affective style.