Attention and memory deficits in schizophrenia: the role of symptoms of depression.

BACKGROUND: Schizophrenic patients suffer from neuropsychologic impairments in several cognitive domains, that is, attention and memory. Similar impairments have been observed in patients with depression. Therefore, the question arises whether and how the symptoms of depression seen in many patients with schizophrenia are linked to their neuropsychologic functioning. METHODS: Seventeen schizophrenic in-patients (after attenuation of acute psychosis) and 17 healthy control subjects matched for sex, age, and education were investigated by use of an neuropsychologic test battery targeting at attention and memory. Symptoms of depression were evaluated by use of 3 self-rating scales and the Hamilton Depression Rating Scale. RESULTS: Patients performed significantly worse in all neuropsychologic tests applied, except in digit span. Additionally, patients exhibited significantly higher levels of depression according to all 3 self-rating scales and moderate depression severity according to the Hamilton Depression Rating Scale (mean: 13.1). By taking the proportion of variance explained by the self-ratings of depression statistically into account, significant group differences disappeared in half of the attention measures and in all memory measures. CONCLUSIONS: These results suggest that part of the neuropsychologic impairments seen in schizophrenia is linked with symptoms of depression. This seems to be especially true for attention and memory disturbances.     

Evaluating cognitive impairment in depression with the Luria-Nebraska Neuropsychological Battery: severity correlates and comparisons with nonpsychiatric controls

Depressed patients often complain of memory and attentional difficulties, and some research suggests an increased incidence of neuropsychological impairment in depression. Yet, many prior studies contain methodological problems, including the following: (1) inclusion of medicated patients, (2) small sample sizes, and (3) tests with unknown psychometric properties. We administered the Luria-Nebraska Neuropsychological Battery (LNNB) to 28 unmedicated inpatients who met Research Diagnostic Criteria for major depression. Twenty of the 28 patients were given additional cognitive measures (e.g., Wechsler Adult Intelligence Scale-Revised, Benton Tests). The depressed patients performed similarly to an age- and education-matched nonpsychiatric reference sample. When data for a subset of the most severely depressed patients were analyzed separately, these patients too were found to perform similarly to matched controls. There were no relationships between Hamilton rating scale measures of depression severity and any cognitive measures among the depressed patients. The results suggest that cognitive functioning in depressed patients does not differ significantly from that in carefully matched controls and is independent of symptom severity.     

Distinct profiles of neurocognitive function in unmedicated unipolar depression and bipolar II depression.

BACKGROUND: Studies have demonstrated neuropsychological deficits across a variety of cognitive domains in depression. Few studies have directly compared depressed subjects with major depressive disorder (MDD) and bipolar disorder (BD), and many are confounded by medication status across subjects. In this study, we compared the performance of unmedicated currently depressed MDD and BD groups on a battery of neuropsychological tests that included measures of risk taking and reflection impulsivity. METHODS: Twenty-two MDD, seventeen BDII, and 25 healthy control subjects (HC), matched for age and IQ, were assessed on a battery of neuropsychological tests. RESULTS: The depressed groups showed comparable ratings of depression severity and age of illness onset. The MDD group was impaired on tests of spatial working memory and attentional shifting, sampled less information on a test of reflection impulsivity, and was oversensitive to loss trials on a decision-making test. The BDII subjects were generally intact and did not differ significantly from control subjects on any test. CONCLUSIONS: These data indicate differing profiles of cognitive impairment in unmedicated depressed MDD versus BDII subjects. Moderately depressed BDII subjects displayed relatively intact cognitive function, whereas MDD subjects demonstrated a broader range of executive impairments. These cognitive deficits in depression were not attributable to current medication status.     

Cognitive functioning in a population-based sample of young adults with anxiety disorders

Objective

Cognitive functioning in anxiety disorders has received little investigation, particularly among young adults and in non-clinical samples. The present study examined cognitive functioning in a population-based sample of young adults with anxiety disorders in comparison to healthy peers.

Methods

A population-based sample of 21–35-year-olds with a lifetime history of anxiety disorders (n = 75) and a random sample of healthy controls (n = 71) derived from the same population were compared in terms of performance in neuropsychological tests measuring verbal and visual short-term memory, verbal long-term memory, attention, psychomotor processing speed, and executive functioning.

Results

In general, young adults with anxiety disorders did not have major cognitive impairments when compared to healthy peers. When participants with anxiety disorder in remission were excluded, persons with current anxiety disorder scored lower in visual working memory tests. Current psychotropic medication use and low current psychosocial functioning associated with deficits in executive functioning, psychomotor processing speed, and visual short-term memory.

Conclusion

Lifetime history of anxiety disorders is not associated with cognitive impairment among young adults in the general population. However, among persons with anxiety disorders, current psychotropic medication use and low psychosocial functioning, indicating more severe symptoms, may associate with cognitive impairments.     

Epidemiology of apathy in older adults: the Cache County Study.

OBJECTIVES: The objectives of this study are to describe the distribution of apathy in community-based older adults and to investigate its relationships with cognition and day-to-day functioning. METHODS: Data from the Cache County Study on Memory, Health and Aging were used to estimate the frequency of apathy in groups of elders defined by demographic, cognitive, and functional status and to examine the associations of apathy with impairments of cognition and day-to-day functioning. RESULTS: Apathy was measured with the Neuropsychiatric Inventory. Clinical apathy (Neuropsychiatric Inventory score > or = 4) was found in 1.4% of individuals classified as cognitively normal, 3.1% of those with a mild cognitive syndrome, and 17.3% of those with dementia. Apathy status was associated with cognitive and functional impairments and higher levels of stress experienced by caregivers. Among participants with normal cognition, apathy was associated with worse performance on the Mini-Mental State Examination, the Boston Naming and Animal Fluency tests, and the Trail Making Test-Part B. The association of apathy with cognitive impairment was independent of its association with Neuropsychiatric Inventory depression. CONCLUSIONS: In a cohort of community-based older adults, the frequency and severity of apathy is positively correlated with the severity of cognitive impairment. In addition, apathy is associated with cognitive and functional impairments in elders adjudged to have normal cognition. The results suggest that apathy is an early sign of cognitive decline and that delineating phenotypes in which apathy and a mild cognitive syndrome co-occur may facilitate earlier identification of individuals at risk for dementia.     

How Late-Life Depression Affects Cognition: Neural Mechanisms

Late-life depression is a major health problem and a significant cause of dysfunction that warrants closer evaluation and study. In contrast to younger depressed patients, most depressed older adults suffer more severe variants of the disorder, including significant cognitive impairments. These cognitive changes add to the severity of symptoms and disability that older depressed patients face and likely reflect compromise of certain neural circuits, linking cognitive impairment to late-life depression. Studies examining clinical correlates, neuropsychological testing, and functional and anatomic imaging have yielded a clearer understanding of the neural mechanisms underlying cognitive deficits in late-life depression. This article discusses cognitive impairment in geriatric depression and how developing a better understanding of its neural correlates may lead to improved understanding and outcome of this specific disorder.     

Neuropsychological deficits and functional impairment in bipolar depression, hypomania and euthymia

OBJECTIVE: To examine whether patients with bipolar disorder (BD) have subtle neuropsychological deficits that manifest clinically as cognitive and functional compromise, and this study attempted to determine the pattern of such cognitive deficits and their functional impact across all three phases of BD. We hypothesised that euthymia does not equate with normal neuropsychological function and that each phase has a characteristic pattern of deficits, with disturbance in attention and memory being common across all phases of the illness: (i) bipolar depression - psychomotor slowing and impairment of memory; (ii) hypomania by frontal-executive deficits and (iii) euthymia - a mild disturbance of attention, memory and executive function. METHODS: Twenty-five patients with a diagnosis of bipolar I disorder underwent neuropsychological testing over a period of 30 months in the natural course of their illness while hypomanic and/or depressed and/or euthymic. The results from these assessments were compared with findings from neuropsychological tests conducted on 25 healthy controls matched for age, sex, education and handedness. RESULTS: Initial analyses revealed modest impairment in executive functioning, memory and attention in both hypomanic and depressed bipolar patients, with additional fine motor skills impairment in the latter. Memory deficits, also noted in euthymic patients, were non-significant after controlling for confounding variables, although bipolar depressed patients remained significantly impaired on tests of verbal recall. Bipolar depressed and hypomanic patients differed with respect to the nature of their memory impairment. Depressed patients were more impaired as compared with euthymic patients on tests of verbal recall and fine motor skills. Psychosocial functioning was impaired across all three patient groups, but only in depressed and hypomanic patients did this correlate significantly with neuropsychological performance. CONCLUSIONS: The mood-state-related cognitive deficits in both bipolar depression and hypomania compromise psychosocial function when patients are unwell. In euthymic patients, subtle impairments in attention and memory suggest that an absence of symptoms does not necessarily equate to 'recovery'. The possibility of persistent cognitive deficits in BD is an issue of profound clinical and research interest that warrants further investigation; however, future research needs to adopt more sophisticated neuropsychological probes that are able to better define state and trait deficits and determine their functional impact.     

Longitudinal association of initiation/perseveration and severity of geriatric depression.

OBJECTIVE: Many older adults with major depression (MDD) present with impairment in initiation and perseveration (IP) tests. However, it remains unclear how these abnormalities change during the course of depression. METHODS: The authors studied the longitudinal covariation of depression severity and IP functioning in 157 depressed older adults with MDD. Patients with and without baseline IP impairment were studied on three occasions over 1 year. RESULTS: Depression severity was associated with concurrent IP scores; however, despite IP improvement, those with impaired baseline IP functioning did not reach the level of their non-impaired counterparts. CONCLUSION: The persistence of IP abnormalities suggests that these patients require careful treatment planning and follow-up, given that earlier studies noted an association of abnormal IP with disability and poor outcomes of depression treatment.     

Neurocognitive function in unmedicated manic and medicated euthymic pediatric bipolar patients

OBJECTIVE: A systematic evaluation of neuropsychological functioning in individuals with pediatric bipolar disorder is necessary to clarify the types of cognitive deficits that are associated with acutely ill and euthymic phases of the disorder and the effects of medication on these deficits. METHOD: Unmedicated (N=28) and medicated (N=28) pediatric bipolar patients and healthy individuals (N=28) (mean age=11.74 years, SD=2.99) completed cognitive testing. Groups were matched on age, sex, race, parental socioeconomic status, general intelligence, and single-word reading ability. A computerized neurocognitive battery and standardized neuropsychological tests were administered to assess attention, executive function, working memory, verbal memory, visual memory, visuospatial perception, and motor skills. RESULTS: Subjects with pediatric bipolar disorder, regardless of medication and illness status, showed impairments in the domains of attention, executive functioning, working memory, and verbal learning compared to healthy individuals. Also, bipolar subjects with comorbid attention deficit hyperactivity disorder (ADHD) performed worse on tasks assessing attention and executive function than patients with bipolar disorder alone. CONCLUSIONS: The absence of differences in the deficits of neurocognitive profiles between acutely ill unmedicated patients and euthymic medicated patients suggests that these impairments are trait-like characteristics of pediatric bipolar disorder. The cognitive deficits found in individuals with pediatric bipolar disorder suggest significant involvement of frontal lobe systems supporting working memory and mesial temporal lobe systems supporting verbal memory, regardless of ADHD comorbidity.     

Cognitive impairment and the brain dopaminergic system in Parkinson disease: [18F]fluorodopa positron emission tomographic study

OBJECTIVE: To investigate the role of the brain dopaminergic system in cognitive impairment in patients with Parkinson disease (PD). DESIGN: We studied 28 patients with PD and 16 age-matched healthy control subjects using [18F] fluorodopa (fluorodopa F 18) positron emission tomography. Patients with PD showed a variable degree of cognitive impairment, which was assessed using the Mini-Mental State Examination and detailed neuropsychologic assessment, including tests sensitive for frontal lobe function. RESULTS: [18F] Fluorodopa uptake was reduced in the putamen (to 36% of the control mean; P<.001), the caudate nucleus (to 61% of the control mean; P<.001), and the frontal cortex (to 45% of the control mean; P<.001) in patients with PD compared with controls. There was no significant association between the degree of overall cognitive impairment of patients and [18F] fluorodopa uptake values. The influx constant (Ki(occ)) in the caudate nucleus had a negative association with performance in the attention-demanding Stroop interference task, especially with the interference time. The Ki(occ) in the frontal cortex had a positive correlation with performance in the digit span (backwards), verbal fluency, and verbal immediate recall tests. Thus, the better the patient performed in tasks demanding immediate and working memory and executive strategies, the better the [18F] fluorodopa uptake in the frontal cortex. In the putamen, no significant correlation was seen between the Ki(occ) value and any of the cognitive tests. The severity of the motor symptoms of PD and [18F]fluorodopa uptake showed a negative correlation in the putamen (r = -0.38; P = .04), and in the caudate nucleus a similar trend was seen (r = -0.36; P = .06). CONCLUSIONS: Reduced [18F]fluorodopa uptake in PD in the caudate nucleus (and frontal cortex) is related to impairment in neuropsychologic tests measuring verbal fluency, working memory, and attentional functioning reflecting frontal lobe function. This indicates that dysfunction of the dopamine system has an impact on the cognitive impairment of patients with PD. However, our results do not exclude the possibility of more generalized cognitive impairment in PD, the pathophysiology of which is probably different and more generalized.     

Cognitive workload across the spectrum of cognitive impairments: A systematic review of physiological measures

Our objective was to identify the physiological measures that are sensitive to assessing cognitive workload across the spectrum of cognitive impairments. Three database searches were conducted: PubMed, PsychINFO, and Web of Science. Studies from the last decade that used physiological measures of cognitive workload in older adults (mean age >65 years-old) were reviewed. The cognitive workload of healthy older individuals was compared with the cognitive workload of younger adults, patients with mild cognitive impairment (MCI), and patients with Alzheimer’s diseases (AD). The most common measures of cognitive workload included: electroencephalography, magnetoencephalography, functional magnetic resonance imaging, pupillometry, and heart rate variability. These physiological measures consistently showed greater cognitive workload in healthy older adults compared to younger adults when performing the same task. The same was observed in patients with MCI compared to healthy older adults. Behavioral performance declined when the available cognitive resources became insufficient to cope with the cognitive demands of a task, such as in AD. These findings may have implications for clinical practice and future cognitive interventions.     

Persistent mild cognitive impairment in geriatric depression

BACKGROUND: Cognitive impairment often occurs with geriatric depression and impairments may persist despite remission of depression. Although clinical definitions of mild cognitive impairment (MCI) have typically excluded depression, a neuropsychological model of MCI in depression has utility for identifying individuals whose cognitive impairments may persist or progress to dementia. METHODS: At baseline and 1-year follow-up, 67 geriatric patients with depression had a comprehensive clinical examination that included depression assessment and neuropsychological testing. We defined MCI by a neuropsychological algorithm and examined the odds of MCI classification at Year 1 for remitted depressed individuals with baseline MCI, and examined clinical, functional and genetic factors associated with MCI. RESULTS: Fifty-four percent of the sample had MCI at baseline. Odds of MCI classification at Year 1 were four times greater among patients with baseline MCI than those without. Instrumental activities of daily living were associated with MCI at Year 1, while age and APOE genotype was not. CONCLUSIONS: These results confirm previous observations that MCI is highly prevalent among older depressed adults and that cognitive impairment occurring during acute depression may persist after depression remits. Self-reported decline in functional activities may be a marker for persistent cognitive impairment, which suggests that assessments of both neuropsychological and functional status are important prognostic factors in the evaluation of geriatric depression.     

Frequency and characteristics of recurrent major depressed patients with unimpaired executive functions.

Major depression is associated with impairment of cognitive functions, and especially higher-order cognitive processes referred to as executive functions (EF). Whether this is a general finding is unclear. Patients without EF impairment may have different treatment needs than patients with EF impairment, and will probably have a better everyday functioning. Thus, it is important to identify the prevalence and characteristics of depressed patients without EF impairment. Forty-three patients with recurrent major depressive disorder (19-51 years) and 50 healthy controls were included in the study. The subjects were assessed with neuropsychological tests selected to measure central areas of EF, and screened on clinical and demographic variables. Within the depressed group, a total of 56% were defined as EF unimpaired. These patients were characterised by higher intellectual abilities and fewer depression episodes than the subgroup of patients with EF impairment. The subgroups were similar in age at debut of illness, severity of depression, general psychopathology and global level of functioning. In conclusion, about half of patients with recurrent major depression have normal EF. Since cognitive impairment and depressive symptomatology seem to be distinct dimensions, a neuropsychological investigation could help to ensure optimal treatment in patients with recurrent major depression.     

Cognitive function in multiple sclerosis and its relation to functional abilities

The performance of patients with multiple sclerosis (MS) on selected neuropsychologic tests was examined to ascertain the applicability of such examinations to diagnosis. Twenty-four patients with definite or probable MS, and sixteen age- and education-matched control subjects were given a battery of tests to assess intellectual functions. The results indicate that the MS patients had cognitive impairment. Severity of disability was not significantly correlated with cognitive impairment. Impaired cognitive functioning, which is often not detected through routine examination, may occur in the disease. These deficits may represent manifestations of otherwise undetectable plaques in the subcortical white matter.     

Six-month course of mild cognitive impairment and affective symptoms in late-life depression

Mild cognitive impairment (MCI) is frequent in patients with late-life depression. Previous studies indicate that cognitive performance in these patients is not or only marginally improved when they recover from depression. However, recovery from cognitive impairments due to depression may have a longer time course than recovery from affective symptoms. In a group of 34 elderly depressed patients (mean age: 73.4 years) admitted to a gerontopsychiatric day-clinic, severity of depression and cognitive performance were assessed before the initiation of treatment and were reassessed 6 months later. At admission, 18 of 34 patients (53%) fulfilled the criteria for MCI, with a preponderance of impairments in short-term memory and visuospatial capabilities. At the 6-month follow-up, cognitive performance had not significantly improved for the entire group; 12 of 27 patients (44%) still were fulfilling the criteria for MCI. No relationships could be ascertained between cognitive impairment or functional level and severity or course of depression. Patients with diurnal variations of the depressive symptomatology were less likely to fully recover from depression.     

Neuropsychological deficits in psychotic versus nonpsychotic major depression and no mental illness

OBJECTIVE: At least three studies have indicated that patients with psychotic major depression studied under non-drug-free conditions differ from patients with nonpsychotic major depression and healthy comparison subjects on several measures of neuropsychological performance. The current study explored specific impairments in cognitive function in subjects with psychotic major depression, subjects with nonpsychotic major depression, and healthy comparison subjects studied under drug-free conditions. METHOD: A battery of neuropsychological tests was administered to 11 patients with psychotic major depression, 32 patients with nonpsychotic major depression, and 23 normal comparison subjects under drug-free conditions. The three groups did not differ statistically in age, sex, or level of education. To ensure that participants had minimal levels of severity and endogenicity, all patients were required to have a score of at least 20 on the 21-item Hamilton Depression Rating Scale and a score of at least 7 on the Core Endogenomorphic Scale, which uses eight items from the Hamilton depression scale. RESULTS: Patients with psychotic major depression demonstrated significantly greater impairment than patients with nonpsychotic major depression and/or comparison subjects in attention and response inhibition (as measured by the Stroop color-word subscale score) as well as in verbal declarative memory (as measured by the Paragraph Recall Test). CONCLUSIONS: These data indicate that patients with psychotic major depression demonstrate impairment in functions thought to be mediated by the frontal cortex and mediotemporal lobes.     

Neurocognitive performance in children and adolescents with bipolar disorder: a review

A number of studies have reported the evidence of cognitive deficits in adult bipolar patients. Recently, there has been a shift in research on neurocognitive performance in bipolar disorder (BD) towards examining younger age groups. A review of the literature on neurocognitive impairments in BD in childhood and adolescence was conducted. We searched systematically for studies in samples of age groups younger than 18 years of age in average that included either a healthy control group or normative data for the cognitive tests used. Twenty-one original articles were found and reviewed. Children and adolescents with BD show deficits in a variety of cognitive areas. The most consistent results were found for impairments in verbal memory. A majority of studies also indicated impairments in working memory. Similar pattern of neurocognitive impairment was found in children and adolescents as compared to adults suffering from BD. The neurocognitive deficits need to be recognized and incorporated into individual treatment programs.     

Cognitive deficits in patients with essential tremor

OBJECTIVE: To assess cognitive and affective functioning in patients with essential tremor (ET). BACKGROUND: ET is traditionally thought to occur in isolation, without other neurologic abnormalities or cognitive changes. Recent evidence of gait disturbance and bradykinesia in these patients suggests that the neurologic abnormalities in ET may be more widespread than was once thought. Cognitive function in these patients has not been the subject of in-depth study. METHODS: Cognitive performance and mood were assessed in 18 consecutive patients with ET and 18 consecutive patients with PD who visited the neurosurgical clinic for surgical treatment of their symptoms. RESULTS: The patients with ET were found to have deficits on tests of verbal fluency, naming, mental set-shifting, verbal memory, and working memory, as well as higher levels of depression. In contrast to these areas of deficit, their performance was better than that of the normative sample on several tests of verbal and nonverbal conceptualization and reasoning. Tremor severity was not correlated with cognitive deficits. Patients with PD had deficits on the same tests that were impaired in the ET group and on tests of visuospatial processes. Direct comparison of the ET and PD groups showed greater impairment in facial perception in the PD group and greater impairment in verbal fluency and working memory in the ET group. CONCLUSION: Patients with ET have deficits in specific aspects of neuropsychological functioning, particularly those thought to rely on the integrity of the prefrontal cortex, which suggests involvement of frontocerebellar circuits in this disease.     

Obstructive sleep apnea and neurocognitive performance: the role of cortisol

BackgroundObstructive sleep apnea (OSA) is a prevalent disorder with multiple consequences including negative effects on neurocognitive function. Several domains of cognitive function are impaired in OSA patients, but the mechanisms through which this sleep disorder results in impairment are not clear. Given the well-known effects of cortisol on cognitive function, in particular memory, the dysregulating effects of OSA on cortisol levels are hypothesized as a potential pathway leading to cognitive impairment.MethodsFifty-five participants with OSA (mean apnea-hypopnea index [AHI], 30.3) were assessed over 2 days. Over a 24-h period, blood samples were collected every 2 h to examine cortisol levels. The following night, sleep was monitored with polysomnography (PSG). Participants were given a battery of neurocognitive tests, which assessed seven cognitive domains.ResultsOSA severity assessed by oxygen desaturation index (ODI) was associated with 24-h cortisol levels. AHI, ODI, and nighttime cortisol levels were associated with global deficit scores (GDS) in cognitive functioning, particularly in domains of learning, memory, and working memory (P < .05 for all). Hierarchical linear regression analysis revealed that nighttime cortisol accounted for 9–16% of variance in learning (P = .018), memory (P = .003), and working memory (P = .016) domains, though apnea severity did not significantly predict any additional variance.ConclusionsIn our sample of patients with OSA, nocturnal cortisol levels were associated with neuropsychologic functioning above and beyond the influence of covariates and apnea severity. These findings suggest that OSA-related alterations in cortisol activity may partially explain the pathophysiology of neuropsychologic impairments in sleep apnea.     

Depression and cognitive deficits in geriatric schizophrenia

Objective

Past reports have found patients with comorbid depression and schizophrenia spectrum disorders exhibit greater deficits in memory and attention compared to schizophrenia spectrum disorder patients without depressive symptoms. However, in contrast to younger schizophrenia patients, the few past studies using cognitive screens to examine the relationship between depression and cognition in inpatient geriatric schizophrenia have found that depressive symptomatology was associated with relatively enhanced cognitive performance. In the current study we examined the relationship between depressive symptoms and cognitive deficits in geriatric schizophrenia spectrum disorder patients (n = 71; mean age = 63.7) on an acute psychiatric inpatient service.

Method

Patients completed a battery of cognitive tests assessing memory, attention and global cognition. Symptom severity was assessed via the PANSS and Calgary Depression Scale for Schizophrenia.

Results

Results revealed that geriatric patients' depression severity predicted enhancement of their attentional and verbal memory performance. Patients' global cognitive functioning and adaptive functioning were not associated with their depression severity.

Conclusion

Contrary to patterns typically seen in younger patients and non-patient groups, increasing depression severity is associated with enhancement of memory and attention in geriatric schizophrenia spectrum disorder patients. Also, diverging from younger samples, depression severity was unassociated with patients adaptive and global cognitive functioning.