Signal detection analysis of recognition memory in depressed elderly

Depression and Cognitive Impairment in Institutionalized Older Adults

BACKGROUND

In the last three decades, the relationship between depression and cognition in geriatric patients has been a popular topic among researchers and clinicians. Clinical and epidemiological research has focused on the identification of risk factors that could be modified in pre-dementia syndromes, at a preclinical and early clinical stage of dementia disorders, with specific attention to the role of depression. The objective of this work was to determine the relationship between depressive disorder and cognitive deterioration in institutionalized older adults.

METHODS

In this descriptive, correlational study, data were gathered from two nursing homes in the province of Jaen (Spain), from a random sample of 140 older adults (70 nondependent and 70 dependent). The variables were measured using comprehensive geriatric assessment, the Cambridge Cognitive Test (CAMCOG), and the Geriatric Depression Scale (GDS).

RESULTS

Depression was correlated with cognitive level in the nondependent older adult sample (r = -0.471, p = 0.004). Age was inversely associated with the score obtained in the CAMCOG of the nondependent older adult sample (r = -0.352, p = 0.038). The functional capacity in several activities of daily living was correlated with the score obtained in the CAMCOG in each of the two groups. Depression was more prevalent in the dependent than in the nondependent older adults (82.85 vs. 57.14%). No association was observed between institutionalization time and the score obtained on the cognitive and affective scales (GDS and CAMCOG) in both groups (GDS-nondependent, r = -0.209, p = 0.234; CAMCOG-nondependent, r = 0.007, p = 0.967; GDS-dependent, r = 0.251, p = 0.152; CAMCOG-dependent, r = -0.021, p = 0.907).

CONCLUSION

Depressive symptomatology is associated with cognitive deterioration. Depression is prevalent in institutions that care for older, more dependent adults.

Cognition in mania and depression: psychological models and clinical implications

Affective disorders, including bipolar disorder and major depressive disorder, are highly prevalent throughout the world and are extremely disabling. Diagnostic and Statistical Manual criteria and psychological models strongly implicate cognitive dysfunctions as being integral to our understanding of these disorders. We review the findings from studies that have used neurocognitive tests and functional imaging techniques to explore abnormal cognition in affective disorders. In particular, we highlight the evidence for cognitive dysfunctions that persist into full clinical remission, and the recent trend toward the use of "hot" processing tasks, involving emotionally charged stimuli, as a means of differentiating between the cognitive underpinnings of mania and depression. The clinical relevance of these developments is discussed.

Neuropsychological functioning and MRI signal hyperintensities in geriatric depression

OBJECTIVE

The purpose of this study was to examine the relationship between signal hyperintensities--a probable marker of underlying pathology--on T2-weighted magnetic resonance brain scans and neuropsychological test findings in elderly depressed and normal subjects.

METHOD

Elderly subjects with a DSM-III-R diagnosis of major depression (N=41) and normal elderly comparison subjects (N=38) participated in a magnetic resonance imaging study (1.0-T) of signal hyperintensities in periventricular, deep white matter, and subcortical gray matter. Hard copies of scans were rated in random order by research psychiatrists blind to diagnosis; the modified Fazekas hyperintensity rating scale was used. Cognitive performance was independently assessed with a comprehensive neuropsychological battery. Clinical and demographic differences between groups were assessed by t tests and chi-square analysis. Relationships between neuropsychological performance and diagnosis and hyperintensities and their interaction were analyzed by using analysis of covariance, with adjustment for age and education.

RESULTS

Elderly depressed subjects manifested poorer cognitive performance on several tests than normal comparison subjects. A significant interaction between hyperintensity location/severity and presence/absence of depression on cognitive performance was found: depressed patients with moderate-to-severe deep white matter hyperintensities demonstrated worse performance on general and delayed recall memory indices, executive functioning and language testing than depressed patients without such lesions and normal elderly subjects with or without deep white matter changes.

CONCLUSIONS

Findings validate cognitive performance decrements in geriatric depression and suggest possible neuroanatomic vulnerabilities to developing particular neuropsychological dysfunction in depressed subjects.

Depression and memory in the elderly: a meta-analysis

A meta-analysis (N = 40) of the effects of depression on memory in the elderly (sample mean age > or = 55 years) examined variables potentially accounting for divergent findings in the literature. The distribution of effects was bimodal and the effect sizes were heterogeneous. Compared to controls, groups containing unipolar subjects only were significantly less impaired than were mixed unipolar-bipolar; five of six studies mixing depression subtype were associated with the more negative mode. Samples containing younger depressed subjects (< 45 years) were significantly more impaired and were associated with the more negative mode. Significant group differences were found between studies matching their comparison groups reasonably well on years of education and those that did not. Thoroughness of dementia screening yielded no group differences. Although correlated observations precluded significance tests, larger effects were found for (1) figural (vs. verbal) memory; (2) delayed (vs. immediate) memory; and (3) recognition (vs. free recall and incidental or cued recall; incidental and cued recall effects were nearly identical). Similar effects were found for composite memory scores versus constituent and for various presentation paradigms (e.g., single presentation, selective reminding). Effect sizes for these categories were in the moderate range. Difficulties synthesizing this literature are discussed as are suggested remedies and directions for future research.

Some aspects of memory disorders clearly distinguish dementia of the Alzheimer's type from depressive pseudo-dementia

Two groups of patients affected by mild dementia of the Alzheimer's type (n = 42) or by depressive pseudo-dementia (n = 26) were given a modified version of the Rey's Auditory Verbal Learning Test. The two groups were roughly matched for overall level of cognitive impairment. The main purpose of the research was to determine if some aspects of their memory disorders distinguished the two diagnostic groups. Comparison between results obtained on recall and on recognition measures was of little diagnostic usefulness in distinguishing dementia of the Alzheimer's type (DAT) from depressive pseudo-dementia (DPD). A marked prevalence of the recency over the primary effect in immediate recall, a high rate of forgetting, and the presence of many intrusion errors on delayed recall were observed more frequently in DAT than in DPD patients. None of these indices, however, was sensitive and specific enough to allow a confident diagnostic discrimination at the individual case level. The memory measure which best distinguished DAT from DPD patients was the presence of several false positive errors on delayed recognition because DAT patients adopted a very liberal response bias, endorsing many false recognition errors, whereas DPD patients adopted a conservative criterion and tended to miss real stimuli, rather than making false recognition errors.

Letter matching: effects of age, Alzheimer's disease, and major depression

We compared Alzheimer's disease (AD) patients and Major Depressive Disorder (MDD), Aged normal, and Young normal controls on a letter-matching task designed to measure the time needed to access overlearned linguistic information in long-term memory. Name identity (NI) and physical identity (PI) reaction time and the NI-PI difference were compared for ADs, MDDs, and Aged normals and separately for Aged and Young normal groups. AD subjects had slower NI and PI reaction times and a bigger NI-PI difference than Aged normal and MDD subjects, suggesting that speed of access to overlearned letter-name information in long-term memory is slowed for ADs. There were no reliable differences between Aged normal and MDD subjects. Aged normals had slower NI and PI reaction times and a bigger NI-PI difference than Young normals, suggesting that the highly practiced operations needed to access letter-name information slow with age. A discriminant analysis was used to evaluate the usefulness of the "easy to perform" letter-matching task for diagnostic purposes. Ninety percent of normal and MDD subjects but only 68% of AD subjects were classified correctly.

Primary or depressive dementia: mental status screening

In the course of interviewing a patient, several aspects of everyday functioning must be covered to provide a range of observations necessary to suggest a provisional diagnosis. First organized by Adolf Meyer, the mental status examination consists of several techniques which, in recent times, have been shortened, structured and standardized to cover maximal ground in minimal time. In this article, the most popular scales are reviewed psychometrically for their capacity to detect, as first-stage instruments, cognitive impairment suggestive of primary dementia in the context of varying prevalence rates and confounding factors like sensory impairments, sociodemographics and depressive states. Several of the measures are found adequate in some respects though not in others, but all of the better ones, when used as front line implements during clinical intake, regularly improve detection over base rates. An analytical method modelled on ROC procedures is then described contrasting two of them before newer instruments are considered which aim to improve sensitivity at relatively little cost to specificity.

Confirmatory factor analysis of the short form Beck Depression Inventory in elderly community samples

The factor structure of the Beck Depression Inventory short form (BDI-SF) was investigated in two elderly samples, with the method of confirmatory factor analysis. Four models previously reported for the BDI-SF in the general adult population were compared for goodness of fit to the data for elderly respondents, and the best-fitting model was adjusted further for these data. Each step in the analyses of the BDI-SF responses of 199 elderly subjects from Tampa, Florida, was cross-validated with data from a second sample of 113 elderly subjects from Houston, Texas. The results confirmed that the three-factor model reported by Reynolds and Gould (1981) adequately fit the data from both elderly samples. The three identified factors were termed Negative Self-Esteem, Anergy, and Dysphoria and were considered to correspond with the cognitive, behavioral, and affective components that generally are thought to be part of the depressive syndrome. The internal consistency of the overall BDI-SF was .74 and .80 in the Tampa and Houston samples, respectively. These findings provide evidence for the construct validity of the BDI-SF by confirming that it displays a factor structure in the aged similar to that observed in the general adult population.