Executive dysfunction and the course of geriatric depression

Mild cognitive impairment: searching for the prodrome of Alzheimer's disease

The concept of mild cognitive impairment (MCI) identifies persons who are neither cognitively normal nor demented. There is increasing evidence that MCI defines a group of persons who are at near-term risk of developing dementia and particularly Alzheimer's disease (AD). MCI thus constitutes an attractive target population for preventive treatments of AD. MCI is associated with aging and is more prevalent than dementia. There are several clinical and biological markers that are predictive of MCI prognosis, including depressive symptoms, cognitive deficits, brain imaging and neurochemical findings. The clinician needs to be especially alert to depressive and other mood symptoms which are common in MCI and potentially treatable. Trials of current medications for prevention of MCI progression to dementia have been largely negative. There are observational data suggesting that lifestyle modifications including exercise, leisure activities, cognitive stimulation, and social activities may be effective for prevention of MCI progression. There are many novel therapies currently in trials for early AD, and if effective they may prove to be helpful in prevention of MCI progression as well.

Executive dysfunction in elderly bipolar manic patients

OBJECTIVE

This study used neuropsychological measures of executive skills to examine the functioning of frontostriatal networks in elderly bipolar patients.

DESIGN

The authors hypothesized that elders with bipolar mania would exhibit poor executive functions relative to both elderly comparison subjects and depressed patients.

SETTING

The study was conducted in the geriatric psychiatry services of a university hospital.

PARTICIPANTS

Nondemented elders: 14 with bipolar disorder I, manic (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), 14 with unipolar major depression (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), and 14 nonpsychiatric comparison (NC) subjects.

MEASUREMENTS

Executive functions were assessed with the initiation/perseveration subscale of the Dementia Rating Scale and the manual Go/No-Go tasks from the extended initiation/perseveration scale.

RESULTS

Manic elders demonstrated poor performance on tasks of initiation/perseveration and response inhibition, and performed significantly worse than both depressed patients and NC subjects. In this sample, there was no evidence for a relationship between severity of manic symptoms and executive performance.

CONCLUSION

These findings extend the observation that elderly bipolar manic patients have deficits in executive functioning compared with NC samples and provide evidence that the executive deficits demonstrated by bipolar manic elders can be more severe than those in unipolar depressed elders. As executive functions require frontostriatal integrity, these observations support investigation of specific frontostriatal network abnormalities in late-life bipolar disorder.

Developing an intervention for depressed, chronically medically ill elders: a model from COPD

BACKGROUND

Geriatric depression preferentially afflicts individuals with chronic medical illnesses. Disability, hopelessness, lack of acceptance of antidepressant treatment, and limited problem-solving skills contribute to poor treatment adherence, compromised outcomes, and chronically experienced adversity.

METHODS

This paper uses depression comorbid with chronic obstructive pulmonary disease (COPD) as a model entity to develop an approach for integrating treatment components essential for improving treatment adherence and outcomes.

RESULTS

The behavioral inertia of depression and its coexisting cognitive problems reduce adherence to the sustained and complex demands of the COPD rehabilitation regimen and antidepressant treatment. An intervention identifying reasons for poor treatment adherence and offering direct instructions for addressing them can be combined with problem-solving therapy to target treatment adherence, depressive symptoms, and disability.

CONCLUSIONS

An intervention focusing on treatment adherence and problem-solving skills development may serve as the platform for administering specific treatments to address the interacting problems of depressed medically ill patients.

Regional white matter hyperintensity burden in automated segmentation distinguishes late-life depressed subjects from comparison subjects matched for vascular risk factors

OBJECTIVE

Segmented brain white matter hyperintensities were compared between subjects with late-life depression and age-matched subjects with similar vascular risk factor scores. Correlations between neuropsychological performance and whole brain-segmented white matter hyperintensities and white and gray matter volumes were also examined.

METHOD

Eighty-three subjects with late-life depression and 32 comparison subjects underwent physical examination, psychiatric evaluation, neuropsychological testing, vascular risk factor assessment, and brain magnetic resonance imaging (MRI). Automated segmentation methods were used to compare the total brain and regional white matter hyperintensity burden between depressed patients and comparison subjects.

RESULTS

Depressed patients and comparison subjects did not differ in demographic variables, including vascular risk factor, or whole brain-segmented volumes. However, depressed subjects had seven regions of greater white matter hyperintensities located in the following white matter tracts: the superior longitudinal fasciculus, fronto-occipital fasciculus, uncinate fasciculus, extreme capsule, and inferior longitudinal fasciculus. These white matter tracts underlie brain regions associated with cognitive and emotional function. In depressed patients but not comparison subjects, volumes of three of these regions correlated with executive function; whole brain white matter hyperintensities correlated with executive function; whole brain white matter correlated with episodic memory, processing speed, and executive function; and whole brain gray matter correlated with processing speed.

CONCLUSIONS

These findings support the hypothesis that the strategic location of white matter hyperintensities may be critical in late-life depression. Further, the correlation of neuropsychological deficits with the volumes of whole brain white matter hyperintensities and gray and white matter in depressed subjects but not comparison subjects supports the hypothesis of an interaction between these structural brain components and depressed status.

Anterior cingulate dysfunction in geriatric depression

BACKGROUND

Although several brain abnormalities have been identified in geriatric depression, their relationship to the pathophysiological mechanisms leading to the development and perpetuation of this syndrome remain unclear.

METHODS

This paper reviews findings on the anterior cingulate cortex (ACC) function and on the relationship of ACC abnormalities to the clinical presentation and the course of geriatric depression in order to elucidate the pathophysiological role of ACC in this disorder.

RESULTS

The ACC is responsible for conflict detection and emotional evaluation of error and is connected to brain structures that regulate mood, emotional valence of thought and autonomic and visceral responses, which are functions disturbed in depression. Geriatric depression often is accompanied by abnormalities in some executive functions and has a clinical presentation consistent with ACC abnormalities. Indices of ACC dysfunction are associated with adverse outcomes of geriatric depression.

CONCLUSIONS

Converging findings suggest that at least some ACC functions are abnormal in depression and these abnormalities are pathophysiologically meaningful. Indices of ACC dysfunction may be used to identify subgroups of depressed elderly patients with distinct illness course and treatment needs and serve as the theoretical background for novel treatment development.

The specificity of neuropsychological impairment in predicting antidepressant non-response in the very old depressed

OBJECTIVE

In an earlier report, response inhibition predict antidepressant non-response in late-life depression (Sneed et al., 2007). The purpose of this study was to ascertain whether this effect is specific to response inhibition or whether impairment in other cognitive domains also predicts non-response.

METHOD

Older depressed patients (n = 84) enrolled in an 8-week trial of citalopram were classified as impaired or non-impaired relative to the sample on mental status, psychomotor speed, reaction time, spatial judgment, and memory, and contrasted with regard to antidepressant response.

RESULTS

Patients who were impaired relative to the sample on digit symbol performance did not respond as quickly to citalopram as those who were unimpaired. By the end of the 8-week trial, however, both groups reached the same level of response. Impairment in other domains had no impact on antidepressant response.

CONCLUSIONS

Non-response was not attributable to impairment on any of the neuropsychological tests suggesting that antidepressant non-response is specific to impaired response inhibition.

The cognitive neuropsychology of depression in the elderly

BACKGROUND

The cognitive impairment of older depressed patients with late- as opposed to early-onset illness may show important differences, in that patients with early onset may suffer predominantly from impaired episodic memory, and those with late onset mainly from reductions of executive function and processing speed.

METHOD

We searched Medline and EMBASE as well as individual papers' reference lists for relevant publications, recording comparisons in neuropsychological test results between early-onset depression (EOD), late-onset depression (LOD) and healthy volunteers. Effect sizes are presented for cognitive domains, such as executive function, processing speed, episodic memory, semantic memory and mental state examination.

RESULTS

Patients with LOD showed greater reductions in processing speed and executive function than patients with EOD and controls. Both patient groups showed reduced function in all domains, except mental state, compared with controls.

CONCLUSION

Pronounced executive deficits are typical of the late-onset patients described in published studies, while episodic memory impairment is not specific to early-onset illness. Possible reasons and confounders are discussed.

Frontal and limbic activation during inhibitory control predicts treatment response in major depressive disorder

BACKGROUND

Inhibitory control or regulatory difficulties have been explored in major depressive disorder (MDD) but typically in the context of affectively salient information. Inhibitory control is addressed specifically by using a task devoid of affectively-laden stimuli, to disentangle the effects of altered affect and altered inhibitory processes in MDD.

METHODS

Twenty MDD and 22 control volunteer participants matched by age and gender completed a contextual inhibitory control task, the Parametric Go/No-go (PGNG) task during functional magnetic resonance imaging. The PGNG includes three levels of difficulty, a typical continuous performance task and two progressively more difficult versions including Go/No-go hit and rejection trials. After this test, 15 of 20 MDD patients completed a full 10-week treatment with s-citalopram.

RESULTS

There was a significant interaction among response time (control subjects better), hits (control subjects better), and rejections (patients better). The MDD participants had greater activation compared with the control group in frontal and anterior temporal areas during correct rejections (inhibition). Activation during successful inhibitory events in bilateral inferior frontal and left amygdala, insula, and nucleus accumbens and during unsuccessful inhibition (commission errors) in rostral anterior cingulate predicted post-treatment improvement in depression symptoms.

CONCLUSIONS

The imaging findings suggest that in MDD subjects, greater neural activation in frontal, limbic, and temporal regions during correct rejection of lures is necessary to achieve behavioral performance equivalent to control subjects. Greater activation in similar regions was further predictive of better treatment response in MDD.

[Executive functions in patients with depression. The role of prefrontal activation]

Depression is a multifarious disease, having an impact on most aspects of everyday life. Cognitive deficits cause considerable impairments and restraints in performance and have become one of the major clinical and research foci in recent years. According to previous work, deficits in executive functioning seem to be particularly prominent. At present only a few functional neuroimaging studies investigated the neurofunctional correlates aimed at these deficits by using specific activation tasks. These findings are somewhat controversial, revealing prefrontal hypo- as well as hyperactivation as a substrate of executive performance. This paper reviews current functional neuroimaging findings within a framework of depression as a dysfunction in limbic-cortical circuits. As a conclusion, the concept of "simple" hypofrontality does not offer a satisfactory explanation. Rather, a more dynamic model will be necessary in order to achieve a more realistic concept of executive deficits in depression.

Are there predictors of outcome in depressed elderly nursing home residents during treatment with mirtazapine orally disintegrating tablets?

BACKGROUND

Treatment studies of depression in residential care are limited. Reports of predictors of response are rare. In the largest nursing home prospective antidepressant trial reported, we examined predictors of response.

METHODS

This was a 12-week open-label study of mirtazapine orally disintegrating tablets performed in 30 US nursing homes. Subjects were men and women aged >or=70, with a Mini Mental State Exam (MMSE) score >or=10, who had a depressive disorder that required antidepressant treatment. Mirtazapine was started at 15 mg at bedtime, and adjusted to 15-45 mg/day. A 16-item Hamilton Depression Rating Scale was used to assess depression at baseline, weeks 2, 4, 8, and 12 or early termination.

RESULTS

One hundred and twenty-four patients received at least one dose of study drug and of these, 119 had at least one post-drug assessment. Mean age was 82.9 years and 72% were female. Response rates at 12 weeks were 47% on the HAMD and 54% on the CGI. Age, sex, MMSE score, medical burden, history of prior depression, and baseline HAMD severity were not significantly associated with HAMD response (>or=50% improvement) and in most cases correlations were trivial, <0.1. Advanced age, medical burden, and cognitive impairment did not predict adverse events.

CONCLUSIONS

In this sample of depressed nursing home residents treated with mirtazapine orally disintegrating tablets, advanced age, medical illness, and cognitive impairment did not predict response. The findings suggest that these variables need not be viewed as obstacles to treatment.

The effects of memory, attention, and executive dysfunction on outcomes of depression in a primary care intervention trial: the PROSPECT study

OBJECTIVE

To describe the influence of domains of cognition on remission and response of depression in an intervention trial among older primary care patients.

METHODS

Twenty primary care practices were randomly assigned to Usual Care or to an Intervention consisting of a depression care manager offering algorithm-based care for depression. In all, 599 adults 60 years and older with a depression diagnosis were included in these analyses. Depression severity and remission of depression were assessed by the 24-item Hamilton Depression Rating Scale. The Mini-Mental State Examination (MMSE) was our global measure of cognitive function. Verbal memory was assessed with the memory subscale of the Dementia Rating Scale. Attention was measured with the digit span from the Weschler Adult Intelligence Test. Response inhibition, one of the executive functions, was assessed with the Stroop Color-Word test.

RESULTS

The intervention was associated with improved remission and response rates regardless of cognitive impairment. Response inhibition as measured by the Stroop Color-Word test appeared to significantly modify the intervention versus usual care difference in remission and response at 4 months. Patients in the poorest performance quartile at baseline on the Stroop Color-Word test in the Intervention Condition were more likely to achieve remission of depression at 4 months than comparable patients in Usual Care [odds ratio (OR) = 17.76, 95% Confidence Interval (CI), 3.06, 103.1].

CONCLUSIONS

Depressed older adults in primary care with executive dysfunction have low remission and response rates when receiving usual care but benefit from depression care management.

Cognitive errors, symptom severity, and response to cognitive behavior therapy in older adults with generalized anxiety disorder

OBJECTIVE

Recent research by Wetherell et al. investigating the differential response to group-administered cognitive behavior therapy (CBT) for generalized anxiety disorder (GAD) in older adults found that GAD severity, homework adherence, and psychiatric comorbidity predicted statistically significant improvement. The current study investigated whether the presence/absence of cognitive errors on separate domains of the Mini-Mental State Exam (MMSE) predicted baseline differences in symptom severity and improvement following CBT, above and beyond already established predictors.

METHODS

Baseline characteristics were investigated in a sample of 208 older patients diagnosed with GAD. Predictors of treatment response were examined in a subsample of 65 patients who completed CBT and were included in a prior study by Wetherell et al. of response predictors.

RESULTS

Results from the baseline sample indicated that only subjects who committed an error on the MMSE Working Memory domain exhibited increased severity in anxiety and depressive symptoms. Results from the treatment sample indicated that an error on the MMSE Orientation domain was a significant predictor of outcome at 6-month follow-up, while controlling for previously established predictors. Patients who committed at least one error in this domain showed decreased response relative to patients who committed no errors.

CONCLUSION

In this sample of older adults diagnosed with GAD, poor performance on the MMSE Working Memory domain was associated with increased baseline anxiety and depression, while baseline performance differences on the MMSE Orientation domain predicted outcome six months after CBT intervention.

Response inhibition predicts poor antidepressant treatment response in very old depressed patients

OBJECTIVE

There have been mixed findings regarding the prognostic significance of age of onset, executive dysfunction, and hyperintensity burden on treatment outcome in late-life depression.

METHODS

Growth curve models were fit to data from the only 8-week, double-blind, placebo controlled trial of citalopram (20-40 mg/day) in patients aged 75 years and older with unipolar depression. Baseline assessment included Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) (to determine age at onset), Stroop Color-Word Test (to assess the response inhibition component of execution dysfunction), and structural magnetic resonance imaging (to determine hyperintensity burden).

RESULTS

In the citalopram condition, patients with response inhibition (most impaired quartile) scored higher at endpoint than those without response inhibition. There were no effects for age of onset or hyperintensity load on response in the citalopram condition. In the placebo condition, patients with early-onset depression had higher depression scores at endpoint than patients with late-onset depression.

CONCLUSION

Only response inhibition, a fundamental executive function, predicted poor treatment response to antidepressant medication. Although patients with response inhibition also showed deficits in reaction time, adjusting for reaction time in our final response inhibition model did not substantively change the findings.

Cortical cholinergic denervation is associated with depressive symptoms in Parkinson's disease and parkinsonian dementia

AIM

To investigate the relationship between ratings of depressive symptoms and in vivo cortical acetylcholinesterase (AChE) activity in subjects with Parkinson's disease (PD) and parkinsonian dementia (PDem).

METHODS

Subjects (with PD, n = 18, including subjects with PDem, n = 6, and normal controls, n = 10) underwent [11C]methyl-4-piperidinyl propionate AChE positron emission tomography imaging and clinical assessment including the Cornell Scale for Depression in Dementia (CSDD).

RESULTS

Subjects with PD and PDem had higher scores on the CSDD compared with normal controls: 7.3 (5.4) and 2.8 (2.6), respectively (F = 6.9, p = 0.01). Pooled analysis demonstrated a significant inverse correlation between cortical AChE activity and CSDD scores: R = -0.5, p = 0.007. This correlation remained significant after controlling for Mini-Mental State Examination scores.

CONCLUSION

Depressive symptomatology is associated with cortical cholinergic denervation in PD that tends to be more prominent when dementia is present.

Impact of delirium on cognition, distress, and health-related quality of life after hematopoietic stem-cell transplantation

PURPOSE

To determine the impact of delirium during the acute phase of myeloablative hematopoietic stem-cell transplantation (HSCT) on health-related quality of life (HRQOL), distress, and neurocognitive functioning 30 and 80 days after transplantation.

PATIENTS AND METHODS

Ninety patients completed a battery assessing HRQOL, distress, and neuropsychological functioning before receiving their first HSCT. Delirium was assessed three times per week using the Delirium Rating Scale and the Memorial Delirium Assessment Scale from 7 days before transplantation through 30 days after transplantation. At 30 days after transplantation, distress and neurocognitive functioning were assessed. At 80 days after transplantation, HRQOL, distress, and neuropsychological functioning were re-evaluated.

RESULTS

After adjusting for confounding factors, patients who experienced a delirium episode, versus patients who did not, reported significantly worse depression, anxiety, and fatigue symptoms at 30 days (linear regression beta(s) = 0.2, 0.3, and 0.5, respectively; P < .04). At 80 days, patients with a delirium episode had significantly worse executive functioning (beta = -1.1; P < .02), attention and processing speed (beta(s) = -4.7 and -5.4, respectively; P < .03), mental health on the Medical Outcomes Study Health Survey, 12-item short form (beta = -6.5; P < .02), and anxiety, fatigue, and cancer and treatment distress symptoms (beta(s) = 0.4, 0.6, and 0.3, respectively; P < .03).

CONCLUSION

Patients with a malignancy who experience delirium during myeloablative HSCT showed impaired neurocognitive abilities and persistent distress 80 days after transplantation. Effective prevention or treatment of delirium during HSCT may improve both cognitive and psychological outcomes.

Event-related potentials in an emotional go/no-go task and remission of geriatric depression

Anterior cingulate integrity may be required for antidepressant response. To assess anterior cingulate processes related to treatment response, we studied error-related negativity and error positivity produced during an emotional go/no-go challenge, a task activating the rostral anterior cingulate. Twelve elderly patients with major depression, treated with escitalopram 10 mg daily, were studied. Patients who remained symptomatic after 8 weeks of treatment had larger error-related negativity and smaller error positivity amplitude compared with patients who achieved remission. The error-related negativity is elicited during conflict detection and the error positivity reflects the emotional reaction to error. Thus, these findings suggest that two distinct conflict-processing functions of the anterior cingulate are important for antidepressant response of geriatric depression.

Neuropsychological impairment in major depression: its nature, origin and clinical significance

Neuropsychological impairment is well established as a feature of major depressive disorder (MDD) but studies have shown a variable pattern of impairment. This paper seeks first to clarify this by examining methodological and clinical factors that give rise to variability in study findings. Second, it examines theories of the origin of these neuropsychological abnormalities. Third, it reviews evidence regarding the clinical significance of different patterns of deficit. A selective review was undertaken of the literature with a particular emphasis on methodological factors, the influence of clinical subtypes and prevalent theories of neuropsychological abnormality. Methodological issues and the heterogeneity of MDD account for considerable variability in results. Specific investigation of the subtypes of psychotic MDD, melancholic MDD and bipolar depression reduces this heterogeneity and results are more consistent in the elderly. Hypothalamic-pituitary-adrenal axis dysfunction is associated with neuropsychological dysfunction in MDD although evidence of direct causation is not definitive at present. Impairment of executive and psychomotor function is a consistent finding, particularly in the elderly, and may reflect frontostriatal-limbic dysfunction. There is growing evidence that this may have clinical significance. It is suggested that future research take very careful account of the exact phenotype of MDD. Classification based on neuropsychological profile may, in fact, be useful. Further research should examine further the clinical importance of patterns of neuropsychological impairment.

Dorsolateral prefrontal cortex and anterior cingulate cortex white matter alterations in late-life depression

BACKGROUND

The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) are critical for mood regulation. Alterations in the white matter connections of these regions may impair their role in mood regulation and increase the risk of developing depression. This study used diffusion tensor imaging to examine for white matter microstructural abnormalities of these regions and of central white matter structures in late-life depression.

METHODS

One hundred six elderly depressed subjects and eighty-four elderly nondepressed subjects underwent clinical assessment and diffusion tensor imaging. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in regions of interest placed in the white matter of the DLPFC, ACC, corpus callosum, and internal capsule. Differences between groups were assessed, controlling for age, sex, and total cerebral volume.

RESULTS

After controlling for covariates, depressed subjects had significantly lower FA values in white matter of the right ACC, bilateral superior frontal gyri, and left middle frontal gyrus. There were no significant differences in ADC values.

CONCLUSIONS

Lower FA, representing lower tissue organization, is observed in depressed elders in the DLPFC and right ACC. These findings support the hypothesis that altered connectivity between brain regions contributes to the risk of depression.

Is depression different in older adults?

Psychiatric disorders such as depression are common conditions in older adults. Depression presents similarly to younger adults, but with more psychotic symptoms and apathy. Research has suggested that genetics play a less important role in the etiology of depression in the elderly, but that other biological factors may be more significant. Vascular pathology in particular is thought to be especially important. White-matter hyperintensities are found in the frontal lobes and basal ganglia in greater numbers in older adults with depression, with damage to the frontal–subcortical circuits thought to be particularly important. It is associated with treatment resistance. Prognosis is poor if depression is not detected and treated adequately and this may lead to a higher risk of dementia and death. However, treatment with selective serotonin reuptake inhibitors and other antidepressants, plus psychological therapies, are effective in the older depressed patient and reduce morbidity and mortality.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Course and outcomes of depression in the elderly

Major depressive disorder is a potentially debilitating condition that often is unrecognized or undertreated in the elderly. Even when aggressively treated, the course of geriatric depression can be severe. There is growing evidence that suggests that late-life depression may carry a higher illness burden than depression with onset earlier in life, and that severity is linked to medical and psychiatric comorbidity. Data continue to accumulate in support of various treatment modalities, including medication, electroconvulsive therapy, and psychotherapy. Given the increased risk of adverse outcomes associated with geriatric depression, such as dementia and suicide, it is essential that future investigations continue to build on the evidence base supporting improved diagnosis and treatment of this complex disorder.