Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electroencephalography (EEG) and related methodologies offer the promise of predicting the likelihood that novel therapies and compounds will exhibit clinical efficacy early in preclinical development. These analyses, including quantitative EEG (e.g. brain mapping) and evoked/event-related potentials (EP/ERP), can provide a physiological endpoint that may be used to facilitate drug discovery, optimize lead or candidate compound selection, as well as afford patient stratification and Go/No-Go decisions in clinical trials. Currently, the degree to which these different methodologies hold promise for translatability between preclinical models and the clinic have not been well summarized. To address this need, we review well-established and emerging EEG analytic approaches that are currently being integrated into drug discovery programs throughout preclinical development and clinical research. Furthermore, we present the use of EEG in the drug development process in the context of a number of major central nervous system disorders including Alzheimer's disease, schizophrenia, depression, attention deficit hyperactivity disorder, and pain. Lastly, we discuss the requirements necessary to consider EEG technologies as a biomarker. Many of these analyses show considerable translatability between species and are used to predict clinical efficacy from preclinical data. Nonetheless, the next challenge faced is the selection and validation of EEG endpoints that provide a set of robust and translatable biomarkers bridging preclinical and clinical programs.
 ...
PMID:Aligning strategies for using EEG as a surrogate biomarker: a review of preclinical and clinical research. 2093 62

Evidence from neuroimaging studies indicates that depressive symptomatology is associated with inefficient recruitment of prefrontal brain regions while performing tasks that tax executive function. In the current study, we investigated the time-course and ERP signature of inefficient executive functioning using a verbal Stroop color-naming task. Twenty (20) undergraduates with moderate to severe BDI-II depression scores and 20 low-scoring controls completed the task. Performance measures did not differ between the two groups. Overt reaction and P300 latencies indicated that all participants showed prominent Stroop effects, such that incongruent responses were delayed compared to congruent. Effects of task condition on the frontal N450 indicated that depressive participants differentiated congruent and incongruent trials earlier than did controls, and that the size of the congruency effect on the N450 was related to self-reported trait rumination among depressive participants. Following this effect, depressive participants showed larger P300s, suggesting an over-commitment of cognitive control resources in the depressive participants. These data lend further evidence to the cortical inefficiency hypothesis and extend the literature by indicating possible improper timing of neural activations during an executive task in depressive undergraduates.
 ...
PMID:Cognitive inefficiency in depressive undergraduates: stroop processing and ERPs. 2118 50

Depression is a major public health concern, and the period from late childhood through early adolescence is a critical time in the development of depressive symptoms. In adults, depression and depressive symptoms are associated with a reduction in the feedback negativity (FN), an ERP component elicited by feedback indicating rewards versus losses. The current study sought to extend these findings to a sample of 64 children aged 8-13, and to examine developmental differences in the FN. Consistent with previous work in adults, higher depressive symptom scores were associated with a blunted FN across the sample. When responses to losses and gains were examined separately, only reduction in the response to monetary gain was associated with increased depressive symptoms. In the current study, the vast majority of children were pre-pubertal, and the FN was unrelated to both age and pubertal development. The FN may be an ideal biomarker for studying changes in reward sensitivity and depression that emerge as children transition through puberty.
 ...
PMID:Neural response to reward and depressive symptoms in late childhood to early adolescence. 2201 9

In ADHD several EEG biomarkers have been described before, with relevance to treatment outcome to stimulant medication. This pilot-study aimed at personalizing neurofeedback treatment to these specific sub-groups to investigate if such an approach leads to improved clinical outcomes. Furthermore, pre- and post-treatment EEG and ERP changes were investigated in a sub-group to study the neurophysiological effects of neurofeedback. Twenty-one patients with ADHD were treated with QEEG-informed neurofeedback and post-treatment effects on inattention (ATT), hyperactivity/impulsivity (HI) and comorbid depressive symptoms were investigated. There was a significant improvement for both ATT, HI and comorbid depressive complaints after QEEG-informed neurofeedback. The effect size for ATT was 1.78 and for HI was 1.22. Furthermore, anterior individual alpha peak frequency (iAPF) demonstrated a strong relation to improvement on comorbid depressive complaints. Pre- and post-treatment effects for the SMR neurofeedback sub-group exhibited increased N200 and P300 amplitudes and decreased SMR EEG power post-treatment. This pilot study is the first study demonstrating that it is possible to select neurofeedback protocols based on individual EEG biomarkers and suggests this results in improved treatment outcome specifically for ATT, however these results should be replicated in further controlled studies. A slow anterior iAPF at baseline predicts poor treatment response on comorbid depressive complaints in line with studies in depression. The effects of SMR neurofeedback resulted in specific ERP and EEG changes.
 ...
PMID:The effects of QEEG-informed neurofeedback in ADHD: an open-label pilot study. 2244 98

An exaggerated response to emotional stimuli is among the many symptoms widely reported by veterans of the 1991 Persian Gulf War. These symptomologies have been attributed to damage and dysfunction associated with deployment-related exposures. We collected event-related potential data from 22 veterans meeting Haley criteria for Gulf War (GW) Syndromes 1-3 and from 8 matched GW veteran controls, who were deployed but not symptomatic, while they performed a visual three-condition oddball task where images authenticated to be associated with the 1991 Persian Gulf War were the distractor stimuli. Hyperarousal reported by ill veterans was significantly greater than that by control veterans, but this was not paralleled by higher amplitude P3a in their ERP responses to GW-related distractor stimuli. Whereas previous studies of PTSD patients have shown higher amplitude P3b responses to target stimuli that are placed amid trauma-related nontarget stimuli, ill veterans in this study showed P3b amplitudes to target stimuli - placed amid GW-related nontarget stimuli - that were significantly lower than those of the control group. Hyperarousal scores reliably predicted P3b, but not P3a, amplitudes. Although many factors may contribute to P3b amplitude differences - most notably depression and poor sleep quality, symptoms that are prevalent in the GW syndrome groups - our findings in context of previous studies on this population are consistent with the contention that dysfunction in cholinergic and dopaminergic neurotransmitter systems, and in white matter and basal ganglia may be contributing to impairments in GW veterans.
 ...
PMID:Visual event-related potentials as markers of hyperarousal in Gulf War illness: evidence against a stress-related etiology. 2314 40

The aim of study was to assess cognition in patients with late onset depression in a symptom-free remission period measuring event-related potentials and reaction times (RT) in a modified computer version of the Stroop test. Thirty four patients with late-onset depression were included after they had reached remission. They were compared to age-, gender- and education-matched healthy controls. Each participant completed a single item computer version of the Stroop Color-word task using verbal response mode. EEG and RT were simultaneously recorded. RTs were significantly prolonged in patients in all conditions of the Stroop paradigm, and the interference effect was significantly greater in patients compared to controls. Results also revealed abnormal late positive Stroop related potentials in the period of about 500-600 ms period corresponding to the so-called P300b wave. Our study supports the view that patients with late onset depression are also cognitively impaired and that this impairment persists in the period of early remission. Using more sensitive ERP measurement of the Stroop task we demonstrated impaired information processing at an earlier, pre-response related stage.
 ...
PMID:Cognition in late onset depression. 2347

Affective state can influence cognition leading to biased information processing, interpretation, attention, and memory. Such bias has been reported to be essential for the onset and maintenance of different psychopathologies, particularly affective disorders. However, empirical evidence has been very heterogeneous and little is known about the neurophysiological mechanisms underlying cognitive bias and its time-course. We therefore investigated the interpretation of ambiguous stimuli as indicators of biased information processing with an ambiguous cue-conditioning paradigm. In an acquisition phase, participants learned to discriminate two tones of different frequency, which acquired emotional and motivational value due to subsequent feedback (monetary gain or avoidance of monetary loss). In the test phase, three additional tones of intermediate frequencies were presented, whose interpretation as positive (approach of reward) or negative (avoidance of punishment), indicated by a button press, was used as an indicator of the bias. Twenty healthy volunteers participated in this paradigm while a 64-channel electroencephalogram was recorded. Participants also completed questionnaires assessing individual differences in depression and rumination. Overall, we found a small positive bias, which correlated negatively with reflective pondering, a type of rumination. As expected, reaction times were increased for intermediate tones. ERP amplitudes between 300 and 700 ms post-stimulus differed depending on the interpretation of the intermediate tones. A negative compared to a positive interpretation led to an amplitude increase over frontal electrodes. Our study provides evidence that in humans, as in animal research, the ambiguous cue-conditioning paradigm is a valid procedure for indirectly assessing ambiguous cue interpretation and a potential interpretation bias, which is sensitive to individual differences in affect-related traits.
 ...
PMID:Indirect assessment of an interpretation bias in humans: neurophysiological and behavioral correlates. 2378 Nov 93

Depression has been associated with task-relevant increased attention toward negative information, reduced attention toward positive information, or reduced inhibition of task-irrelevant negative information. This study employed behavioural and psychophysiological measures (event-related potentials; ERP) to examine whether groups with risk factors for depression (past depression, current dysphoria) would show attentional biases or inhibitory deficits related to viewing facial expressions. In oddball task blocks, young adult participants responded to an infrequently presented target emotion (e.g., sad) and inhibited responses to an infrequently presented distracter emotion (e.g., happy) in the context of frequently presented neutral stimuli. Previous depression was uniquely associated with greater P3 ERP amplitude following sad targets, reflecting a selective attention bias. Also, dysphoric individuals less effectively inhibited responses to sad distracters than non-dysphoric individuals according to behavioural data, but not psychophysiological data. Results suggest that depression risk may be most reliably characterised by increased attention toward others' depressive facial emotion.
...
PMID:Biased processing of sad faces: an ERP marker candidate for depression susceptibility. 2408 51

Cognitive behavioural therapy (CBT) is a well-established treatment for obsessive-compulsive disorder (OCD). However, few patients receive CBT, due to factors such as geographic limitations, perceived stigmatization, and lack of CBT services. Technology-delivered cognitive behavioural therapy (T-CBT) could be an effective strategy to improve patients' access to CBT. To date, a meta-analysis on the effectiveness of T-CBT for OCD has not been conducted. This study used meta-analytic techniques to summarize evidence on the efficacy of T-CBT for OCD versus control conditions and therapist-administered CBT. A meta-analysis according to Prisma guidelines was conducted on randomized controlled trials (RCTs) of T-CBT for OCD. Treatment was classified as T-CBT if evidence-based CBT active ingredients for OCD were included (psychoeducation, ERP, and cognitive restructuring), delivered through health technologies (e.g. self-help books, leaflets, and other forms of bibliotherapy) or remote communication technologies (e.g. the Internet, web-cameras, telephones, telephone-interactive voice response systems, and CD-ROMS). Studies using validated outcomes for OCD or depression were included. Eight trials were included (N = 420). Two trials were classified as at high risk of bias. T-CBT seemed to be superior to control conditions on OCD symptom outcomes at post-treatment (d = 0.82, 99% CI = 0.55-1.08, p = 0.001), but not on comorbid depression (d = 0.33, 99% CI = - 0.01-0.67, p = 0.020). Difference in the efficacy on OCD symptoms between T-CBT and therapist-administered CBT was not significant, despite a trend favouring therapist-administered CBT emerged (d = 0.45, 95% CI = 0.03-0.87, p = 0.033). Directions for research are discussed. Further RCTs are warranted to examine the efficacy of T-CBT for OCD.
 ...
PMID:Efficacy of technology-delivered cognitive behavioural therapy for OCD versus control conditions, and in comparison with therapist-administered CBT: meta-analysis of randomized controlled trials. 2570 87

Adapting behavior to dynamic stimulus-reward contingences is a core feature of reversal learning and a capacity thought to be critical to socio-emotional behavior. Impairment in reversal learning has been linked to multiple psychiatric outcomes, including depression, Parkinson's disorder, and substance abuse. A recent influential study introduced an innovative laboratory reversal-learning paradigm capable of disentangling the roles of feedback valence and expectancy. Here, we sought to use this paradigm in order to examine the time-course of reward and punishment learning using event-related potentials among a large, representative sample (N=101). Three distinct phases of processing were examined: initial feedback evaluation (reward positivity, or RewP), allocation of attention (P3), and sustained processing (late positive potential, or LPP). Results indicate a differential pattern of valence and expectancy across these processing stages: the RewP was uniquely related to valence (i.e., positive vs. negative feedback), the P3 was uniquely associated with expectancy (i.e., unexpected vs. expected feedback), and the LPP was sensitive to both valence and expectancy (i.e., main effects of each, but no interaction). The link between ERP amplitudes and behavioral performance was strongest for the P3, and this association was valence-specific. Overall, these findings highlight the potential utility of the P3 as a neural marker for feedback processing in reversal-based learning and establish a foundation for future research in clinical populations.
 ...
PMID:The temporal dynamics of reversal learning: P3 amplitude predicts valence-specific behavioral adjustment. 2705 20


<< Previous 1 2 3 4 Next >>