Fatigue, Depression and Testing

Response variability is associated with self-reported cognitive fatigue in multiple sclerosis.
Bruce, Jared M., Bruce, Amanda S., Arnett, Peter A.
Neuropsychology, Vol 24(1), Jan, 2010. pp. 77-83.
Abstract:
Cognitive fatigue is a common, often debilitating symptom of multiple sclerosis (MS). Although MS patients frequently report that fatigue negatively affects cognitive functioning, most studies have found little evidence for a direct relationship between self-reported cognitive fatigue and traditional measures of neuropsychological functioning. The purpose of the present study was to examine the association between self-reported cognitivefatigue and a measure of response time variability (RTV). MS patients demonstrated significantly higher RTV than controls, and RTV was highly correlated with self-reported cognitive fatigue among relapsing-remitting and secondary progressive MS patients. Results highlight the need to implement newer methods to further elucidate the relationship between cognitive fatigue and neuropsychological functioning in MS.

Selective attention deficits and subjective fatigue following traumatic brain injury.
Ziino, Carlo., Ponsford, Jennie.
Neuropsychology, Vol 20(3), May, 2006. pp. 383-390.
Abstract:
The present study aimed to investigate the relationship between subjective fatigue and selective attention deficitsfollowing traumatic brain injury (TBI). Forty-six participants with mild-severe TBI and 46 healthy controls completed fatigue scales (Visual Analogue Scale–Fatigue, Fatigue Severity Scale [FSS] and Causes of FatigueQuestionnaire [COF]), and attentional measures including subtests from the Test of Everyday Attention, and the Complex Selective Attention Task (C-SAT). TBI participants reported greater fatigue on the FSS and COF, performed more slowly on attentional measures, and made more errors on the C-SAT. After controlling for anxiety and depression, fatigue was significantly correlated with performance only on the C-SAT. Findings suggest a relationship between subjectivefatigue and impairment on tasks requiring higher order attentional processes.

Depression and memory impairment: A meta-analysis of the association, its pattern, and specificity.
Burt, Diana Byrd. , Zembar, Mary Jo, Niederehe, George
Psychological Bulletin, Vol 117(2), Mar, 1995. pp. 285-305.
Abstract:
The existing evidence paints an unclear picture of whether an association exists between depression and memoryimpairment. The purpose of this investigation was to determine whether depression is associated with memoryimpairment, whether moderator variables determine the extent of this association, and whether any obtained association is unique to depression. Meta-analytic techniques were used to synthesize data from 99 studies on recall and 48 studies on recognition in clinically depressed and nondepressed samples. Associations between memory impairment and other psychiatric disorders (e.g., schizophrenia, dementia) were also examined. A significant, stable association between depression and memory impairment was revealed. Further analysesindicated, however, that it is likely that depression is linked to particular aspects of memory, the linkage is found in particular subsets of depressed individuals, and memory impairment is not unique to depression.

A quantitative review of cognitive deficits in depression and Alzheimer-type dementia.
Christensen, Helen., Griffiths, Kathleen. MacKinnon, Andrew. Jacomb, Patricia
Journal of the International Neuropsychological Society, Vol 3(6), Nov, 1997. pp. 631-651.
Abstract:
Meta-analysis was used to examine the performance of depressed and Alzheimer-type dementia (DAT) patients on standard and experimental clinical tests of cognitive function. Deficits were found for depression on almost every psychological test. Relative to nondepressed controls, the average deficit was 0.63 of a standard deviation, but the magnitude of the effect varied with the type of test. DAT patients performed worse than depressed patients, with an average effect size of 1.21 standard deviations, but the size of the effect depended on the clinical test. Effect sizes for the comparison between depressives and controls were significantly affected by age, treatment setting, ECT use, severity of depression, and the source of diagnostic criteria, but not by the type of depression. Effect sizes in the comparison of depressives to DAT patients were influenced by age, the severity of depression, and ECT. Depressives performed proportionately worse than controls on tasks with pleasant or neutral, compared with unpleasant content, on speeded compared with nonspeeded tasks, and on vigilance tasks. Relative to DAT patients, depressives performed no better on recall compared to recognition tasks, or verbal compared to visual material.

Attention and executive functions in remitted major depression patients.
Paelecke-Habermann, Yvonne., Wittenberg, Halle, Pohl, Johannes. Leplow, Bernd.
Journal of Affective Disorders, Vol 89(1-3), Dec, 2005. pp. 125-135.
Abstract:
Background: Deficits in attention and executive functions in patients with Major Depressive Disorder (MDD) are well confirmed [Veiel, H.O.F., 1997. A preliminary profile of neuropsychological deficits associated with majordepression. Journal of Clinical and Experimental Neuropsychology 19, 587-603.]. The database regarding the relationship between impairments and the duration of disease or the number of episodes is inconsistent. Furthermore, the role of long-term cognitive impairments in MDD during remitted state is not well understood [Elliott, R., 2002. The neuropsychological profile in primary depression. Taylor and Francis, London, pp. 273-293.]. There is consequently a lack of studies accounting for different courses of illness in the euthymic state and considering the influence of possible attentional deficits on executive performance. Methods: 40 euthymic patients with MDD diagnosis according to DSM-IV (20 patients with 1-2 episodes and 20 severe depressives with at least three episodes) as well as 20 healthy controls matched for education and age were administered three tests for attention (attentional shift, Stroop task, sustained attention) and three for executive functions (BADS, word fluency, memory span). The methods selected were theory based with regard to an involvement of frontal-subcortical networks in MDD, attention, and executive functions, respectively. Results: Euthymic patients with MDD showed deficits in all tests related to attentional and executive functions compared to healthy controls. The patient groups did not differ with regard to attentional performance. Executive functions in severe depressives were more impaired than in mild depressives. Limitations: Differing performances of the patient groups in the subtests of the executive test battery (BADS) can only be interpreted to a limited extent. Conclusions: The results support the assumption that deficits in attention and executive functions in MDD show an increase in trait character and executive function during chronic course. Implications for differential diagnosis and cognitive psychotherapy are discussed.

A preliminary profile of neuropsychological deficits associated with major depression.
Veiel, Hans O. F.
Journal of Clinical and Experimental Neuropsychology, Vol 19(4), Aug, 1997. pp. 587-603.
Abstract:
A profile of neuropsychological deficits of clinically depressed (major depression) but otherwise unimpaired individuals is presented, based on a meta-analysis of all studies published since 1975 and meeting stringent methodological and sample selection criteria. Deficits are discussed separately for different cognitive areas in terms of mean size of deficit, variability between studies, variability of individual scores in depressed populations relative to that of controls, and expected proportion of depressed individuals scoring 2 standard deviations or more below the mean of controls. The neuropsychological deficitsof individuals with major depression are shown to be consistent with a global-diffuse impairment of brain functions with particular involvement of the frontal lobes. Recent neuro-imaging studies also indicating frontal dysfunction in clinical (functional) depression are discussed. Both the severity and the profile of cognitive deficiencies in depression are postulated to be similar to those seen in moderately severe traumatic brain injury.

On the nature and pattern of neurocognitive function in major depressive disorder.
Zakzanis, Konstantine K.. Leach, Larry., Kaplan, Edith
Neuropsychiatry, Neuropsychology, & Behavioral Neurology, Vol 11(3), Jul, 1998. pp. 111-119.
Abstract:
An effect size analysis of neurocognitive function in patients with major depressive disorder using meta-analytic principles was conducted. A review of the literature yielded 22 studies published from 1980–1997 that met the criteria for inclusion in the analysis. Results from 726 patients (aged 34–72 yrs) with depression and 795 healthy normal controls reveal that depression had the largest effect on measures of encoding and retrieval from episodic memory. Intermediate effect sizes were recorded on tests of psychomotor speed and tests that require sustained attention. Minimal effect sizes were found on tests of semantic memory, primary memory, and working memory. Moreover, major depressive disorder is accompanied by dysfunction of effortful encoding of information along with an accompanying inefficiency of retrieving poorly encoded information from declarative memory.

Association between depression severity and neurocognitive function in major depressive disorder: A review and synthesis.
McClintock, Shawn M., Husain, Mustafa M., Greer, Tracy L., Cullum, C. Munro.
Neuropsychology, Vol 24(1), Jan, 2010. pp. 9-34.
Abstract:
The effects of major depressive disorder (MDD) on neurocognitive function remain poorly understood. Results from published studies vary widely in terms of methodological factors, and very little is known about the effects of depression severity and other clinical characteristics on neurocognitive function. The purpose of this review was to synthesize prior research findings regarding neurocognitive functioning in patients with MDD and varying levels of depression severity and to provide recommendations for future directions. Overall, this review suggests that MDD has been inconsistently associated with neurocognitive functioning and there is limited understanding regarding the relationship between depression severity and neurocognitive sequelae. There was much heterogeneity on depression severity – related factors across studies assessing neurocognitive function in MDD, as well as substantial variability in the consideration of depression severity among studies, which suggests a need to further explore this important issue.