Slow brain potentials and psychomotor retardation in depression

Applying Gamification Principles and Therapeutic Movement Sequences to Design an Interactive Physical Activity Game: Development Study

BACKGROUND

Depression is a severe illness that has accelerated with the spread of COVID-19 and associated lockdowns. As a result, reported physical activity has substantially decreased, further increasing depressive symptoms.

OBJECTIVE

This study aims to explain the use of gamification principles to develop content for an interactive physical activity game for depression based on clinically proven depression diagnostic criteria.

METHODS

We discuss related work in this field, the game design framework, the users' depression severity, how we customize the contents accordingly, the gradual progression of the game to match exercise principles, and user flow optimization.

RESULTS

We provide a brief description of each of the games developed, including instructions on how to play and design aspects for flow, audio, and visual feedback methods. Exergames (interactive physical activity-based games) stimulate certain physical fitness factors such as improving reaction time, endurance, cardiovascular fitness, and flexibility. In addition, the game difficulty progresses based on various factors, such as the user's performance for successful completion, reaction time, movement speed, and stimulated larger joint range of motions. Cognitive aspects are included, as the user has to memorize particular movement sequences.

CONCLUSIONS

Mental health issues are linked to behavior and movement; therefore, future physical activity-based interactive games may provide excellent stimulation for inducing user flow, while physical activity can help train various physical fitness factors linked to depression.

Loss of automatic processes and blunted-affect in depression: a P3 study

The P3 components (P3a and P3b) of the event-related potentials have been analysed in sixteen in-patients with a major depressive episode (DSM III-R) according to their subtype - anxious-agitated and impulsiveversusretarded and blunted-affect - assuming that these two opposite dimensions of the depressive mood would rely on different physiopathological mechanisms. The P3a component, which indexes automatic cognitive processes, was dramatically decreased in the retarded and blunted-affect group. This suggests that this special type of cognitive dysfunction in depression is rather related to negative symptoms than to depression itself.

Endogenous evoked potentials assessment in depression: a review

Over the past 15 years, researchers have shown an increasing interest in using event-related potentials (ERPs) to study depression. These studies generally fall into four classes: 1), ERPs as a means of detecting depression; 2), ERPs as a tool for distinguishing subtypes of depression; 3), ERPs as a measure of pharmacological effectiveness; 4), ERPs as indicators of defective cognitive operations in depressed subjects. Results from these heterogeneous approaches are often inconsistent and disappointing. Although some ERP components often show increased latencies and diminished amplitudes, these changes seem to reflect principally a variety of non-specific disorders affecting a wide range of cognitive functions rather than a precise and consistent deficit of a particular function. These disappointing results seem to be attributable to methodological problems (heterogeneous patient populations, disproportionate use of the odd-ball paradigm), and do not necessarily call into question the value of studying the ERPs. Furthermore, recent advances in ERP methodology have opened up new perspectives for ERP use in psychopathology.

The functional anatomy of psychomotor disturbances in major depressive disorder

Psychomotor disturbances (PMD) are a classic feature of depressive disorder that provides rich clinical information. The aim our narrative review was to characterize the functional anatomy of PMD by summarizing findings from neuroimaging studies. We found evidence across several neuroimaging modalities that suggest involvement of fronto-striatal neurocircuitry, and monoaminergic pathways and metabolism. We suggest that PMD in major depressive disorder emerge from an alteration of limbic signals, which influence emotion, volition, higher-order cognitive functions, and movement.

Bereitschaftspotential in remitted paediatric bipolar disorder

Bereitschaftspotential (BP) is an anticipatory slow wave in the brain that typically precedes a voluntary motor act and its deficit reflects abnormal motor preparatory processes in the brain. Although BP deficits have been consistently noticed in schizophrenia, similar research in depression has yielded contradictory results; therefore, it is unclear if motor anticipatory processes are actually abnormal in mood disorder. We compared both early and late BP between thirty remitted paediatric bipolar patients (PBD) and thirty matched healthy control group subjects. We did not find any evidence of BP abnormality in PBD, indicating normal motor preparatory processes in this condition. This finding is in agreement with our previous research reporting normal anticipatory slow waves in bipolar subjects. Future research needs to address the specificity of normal anticipatory slow waves in bipolar disorder, compared to other major Psychoses.

Loss of control during instrumental learning: a source localization study

This study used multi-channel electroencephalography (EEG) to investigate cortical correlates of response-outcome contingency appraisal as indexed by the postimperative negative variation (PINV) during instrumental learning. PINV data were subjected to standardized low resolution brain electromagnetic tomography (sLORETA) for source localization. Forty-six healthy adult persons underwent a forewarned S1-S2 paradigm where response-outcome contingencies varied in three consecutive conditions. Initially subjects could control aversive stimulation by a correct behavioral response followed by loss of control and subsequent restitution of control. Throughout the experiment, reaction times, errors, ratings of controllability, arousal, emotional valence and helplessness were assessed. Topographical EEG analyses showed that in particular frontal PINV magnitudes covaried with the experimental manipulation. Loss of control induced extensive response-outcome uncertainty accompanied by a fronto-central PINV maximum. sLORETA functional analyses of the PINV revealed that dependent on the experimental conditions frontal, temporal and parietal areas seem to be related to PINV formation. In particular during loss of control, between-conditions sLORETA comparisons found Brodmann Area 24 in the anterior cingulate cortex (ACC) to be associated with PINV generation, which was confirmed by correlational analyses. These results provide further evidence for the role of the ACC in detecting response conflict and its involvement in the generation of the PINV.

Anticipation of affect in dysthymia: behavioral and neurophysiological indicators

Anticipation for future affective events and prediction uncertainty were examined in healthy controls and individuals with dysthymia (DYS) using behavioral responses and the contingent negative variation (CNV) and post-imperative negative variation (PINV) event-related potential (ERP) components. Warning stimuli forecasted the valence of subsequently presented adjectives ("+", positive; "=", neutral; "-", negative), and participants indicated whether each adjective would describe them over the next two weeks. Controls expected fewer negative, and individuals with DYS expected fewer positive, adjectives to apply to them. CNV amplitudes were enhanced in controls prior to positive versus other adjectives. Response times and PINV amplitudes were greater following neutral compared to other adjectives, and PINV was larger overall in dysthymics compared to controls. In sum, healthy controls and individuals with DYS exhibit different behavioral and neurophysiological biases in anticipation for future affective events. These results are discussed in the context of cognitive theories of depression.

Negative symptoms: A review of schizophrenia, melancholic depression and Parkinson's disease

Negative symptoms generally refer to a reduction in normal functioning. In schizophrenia they encompass apathy, anhedonia, flat affect, avolition, social withdrawal and, on some accounts, psychomotor retardation. Negative symptoms have been identified in other psychiatric disorders, including melancholic depression, and also in neurological disorders, such Parkinson's disease. Achieving a better understanding of negative symptoms constitutes a priority in mental health. Primarily, negative symptoms represent an unrelenting, intractable and disabling feature for patients, often amounting to a severe burden on families, carers and the patients themselves. Identifying and understanding subgroups within disorders may also contribute to the clinical care and scientific understanding of the pathophysiology of these disorders. The purpose of this paper is to review the current literature on negative symptoms in schizophrenia and explore the idea that negative symptoms may play an important role not only in other psychiatric disorders such as melancholic depression, but also in neurological disorders, such as Parkinson's disease. In each disorder negative symptoms manifest with similar motor and cognitive impairments and are associated with comparable neuropathological and biochemical findings, possibly reflecting analogous impairments in the functioning of frontostriatal-limbic circuits.

Neuropsychological test profiles in schizophrenia and non-psychotic depression

OBJECTIVE

The study examined to what degree schizophrenia is characterized by a neuropsychological (NP) test profile specific in shape and level compared with depression and normal functioning.

METHOD

Fifty-three patients with schizophrenia, 45 with non-psychotic depression, and 50 normals were assessed with a comprehensive NP test battery and clinical instruments. NP test scores were factor analyzed into seven composite scores.

RESULTS

Schizophrenia patients performed significantly below normals across all seven composite scores, whereas depression patients were impaired in two. Verbal memory was most impaired. Sixty-two percent of schizophrenia patients were moderately or severely impaired, the corresponding figure for depression was 28%. Impairment was moderately associated with IQ level and clinical symptom load in schizophrenia, but not in depression.

CONCLUSION

Schizophrenia is characterized by deficits across a wide range of NP functions. Thirty-eight percent of the patients are within normal limits. A mild and limited NP disturbance is apparent in depression.

P300 evidence of cognitive inflexibility in female adolescents at risk for recurrent depression

Studies utilizing the P300 event-related potential (ERP) to document potential neurophysiological deficits related to depression have produced variable findings. The present investigation examined the effects of two tasks to determine whether one task would be more sensitive to a history of depression. We examined 124 female subjects, aged 14-20 years. Each subject was assigned to either a history of depression (DEP-Hx) or control group based on the presence versus absence of a DSM-III-R Major Depressive Episode. ERPs were recorded during two auditory oddball tasks. The first task was a simple two-pitch auditory discrimination and the second task was a three-stimulus auditory discrimination. In both tasks, subjects responded to the same rare target tone. Analysis of P300 amplitudes indicated a significant group by task interaction. Simple effects indicated that control subjects exhibited smaller target P300 amplitudes during the three-stimulus task as compared to the two-stimulus task. In contrast, subjects with a history of depression did not show a significant difference in P300 target amplitude between the two tasks. These results suggest that depression history as well as task difficulty/modality may influence the utility of the P300 in documenting the neurophysiological aspects of depression.

Depression and familial risk for substance dependence: a P300 study of young women

The present study evaluated the effects of depression and a family history of alcohol or substance dependence on P300 event-related potentials in young women aged 14 to 20 years. Of the 130 female subjects, 29 met DSM-III-R diagnostic criteria for a lifetime history of a Major Depressive Episode. Event-related electroencephalographic potentials were recorded from each subject while she performed a complex visual oddball task. Analyses indicated a decrement in P300 amplitude in the depressed group as compared to girls with no history of depression. No effects of family history of alcoholism or drug dependence were detected. Current source density analyses, utilizing a realistic head-shape boundary element model, indicated that the difference between the depressed and non-depressed groups was maximal in the right prefrontal region. These results provide further support for the notion that the cognitive difficulties associated with depression are subtle and best detected with sensitive neurophysiological indices, such as P300.

Cortical hypoactivation during resting EEG in schizophrenics but not in depressives and schizotypal subjects as revealed by low resolution electromagnetic tomography (LORETA)

This study was performed in order to address the question whether the newly introduced technique of low-resolution electromagnetic tomography (LORETA) is able to detect hypofrontality in schizophrenic patients. We investigated resting EEGs of 19 unmedicated schizophrenics and 20 normal subjects. For comparison, we also investigated 19 subjects with schizotypal personality and 30 unmedicated depressive patients. A significant increase of delta activity was found in schizophrenic patients over the whole cortex, most strongly in the anterior cingulate gyrus and temporal lobe (fusiform gyrus). Both schizotypal subjects and depressive subjects showed significantly less delta, theta and beta activity in the anterior cingulum, a decrease of alpha1 activity in the right temporal lobe and a decrease of alpha2 activity in the left temporal lobe. The results suggest general cortical hypoactivation, most pronounced in the anterior cingulate and temporal lobe in schizophrenics, whereas there is evidence for a complex, frequency-dependent spatial pattern of hyperactivation in schizotypal subjects and depressive patients. The results are discussed within a neurophysiological and methodological framework.

Event-related potentials and white matter lesions in bipolar disorder

OBJECTIVES

To investigate neurophysiological parameters which possibly distinguish subtypes I and II of patients with a bipolar disorder, and contrast the findings with observations from a group of schizophrenic patients and a group of healthy controls.

METHODS

Sixty-six volunteers underwent a MRI scan to determine the number and location of white matter lesions (WSL). A electrophysiological registration was made while all volunteers performed a auditory 'oddball' task, and the amplitude of the resulting P300 wave was compared.

RESULTS

Earlier reports of higher numbers of WSL in bipolar disorder were not replicated in this study. Subtypes I and II showed a different P300 amplitude and subtype I resembled the results of the schizophrenia group.

CONCLUSION

Bipolar patients in remission have a functional brain disorder that is expressed by a change in physiological response to external stimuli.

Event-Related Potentials and Cognitive Processing of Affectively Toned Words in Depression

Abstract Background: Depressed subjects and euthymic controls demonstrate differences in cognitive processing and brain electrophysiology. Contingent negative variation (CNV) and postimperative negative variation (PINV) was used to investigate the relationship between cognition and cortical event related potentials. Method: Electrophysiological responses and memory of different personality trait adjectives were measured in 15 patients with major depressive disorder and 15 euthymic controls. The words were presented acoustically to elicit event-related potentials. The subjects were asked to indicate whether the words were self-referential. Responses were measured separately for self referential and non-self referential, neutral, positively and negatively toned words. Results: Depressed patients chose more negative and fewer positive words as self-referential, though no significant differences between groups in CNV magnitude for any of the words were found. Persistence of cortical negativity after the motor response (PINV) was significantly (P < 0.02) greater in patients for all non-self-referential words, and reaction times were significantly longer for all words. Recall of positive words and recognition of all words were significantly impaired in patients. Conclusions: Both electrophysiological measures and memory tests found differences between depressed patients and controls, suggesting that the PINV wave may be a useful electrophysiological probe to clarify the neurophysiological basis of cognitive processes.

Bereitschaftspotential in depressed and non-depressed patients with Parkinson's disease

Impaired initiation and slowed execution of movements are two of the principal characteristics of Parkinson's disease (PD). A similar pattern of movement impairments (psychomotor retardation) can be seen frequently in patients with idiopathic depression. In addition, affective disorders have been frequently reported in patients with different basal ganglia disorders. The aim of this study was to determine whether there are some particularities in the cerebral electrical activity during the preparation and execution of voluntary internally paced movements (i.e., Bereitschaftspotential, BP) in depressed PD patients, which can distinguish them from non-depressed PD patients, as well as from healthy controls. The BPs were recorded in 16 patients with idiopathic PD, eight of whom were depressed (PD-D), and eight of whom were not (PD-ND). Additional recordings were taken from a group of eight age- and sex-matched healthy subjects. Depression was classified using the Research Diagnostic Criteria and the two PD groups were matched for age, disease severity, and disease duration. The amplitudes and slopes of the BPs from PD patients were generally smaller than in controls, but there was no specific pattern of BP changes that distinguished depressed from non-depressed PD patients. In addition, there was no particular association between measures of depression severity and BP parameters. The data suggest that presence of depression in PD might not have any additional deteriorating influence on already impaired preparation for self-paced spontaneous movements.

Contingent negative variation and attention in schizophrenic and depressed patients

Contingent negative variation (CNV) is supposed to be a psychophysiological indicator of attention and arousal. Both have been reported to be deteriorated in schizophrenic and depressed patients. Thirty-four patients with major depression, 43 patients with schizophrenia and 49 healthy subjects were investigated during acute illness with a complex three-stimulus go/no-go task which requires different states of attention: trials consisted of three complex figures that were tachistoscopically presented. Three identical figures had to be confirmed by pressing a button (target condition). CNV was measured: (1) after the first figure waiting for the second (baseline condition), (2) after two identical figures waiting for the third (response-relevant condition), (3) after two different figures waiting for the third (response-irrelevant condition). The response-relevant condition compared to baseline significantly intensified CNV in healthy controls and to a minor extent in depressed patients but not in schizophrenics. In the response-relevant conditions in healthy controls, CNV was significantly reduced compared to the response-relevant condition. This clear discrimination between response-relevant and response-irrelevant conditions was not observed in either group of patients. Thus, the applied CNV paradigm was able to discriminate schizophrenic and depressed patients from healthy controls. Furthermore, subtle differences between schizophrenic and depressed patients were detected, reflected by the different CNV development across experimental conditions.

[The p300 cognitive event-related potential. II. Individual variability and clinical application in psychopathology]

The P300 wave is one of the cognitive components of the event-related potential (ERP) that is used to investigate the cognitive processes, and which can be used to study patient populations with a variety of psychiatric disorders. Its clinical utility has been increased by the identification of factors that contribute to the variability in its amplitude and latency. However, its value as a diagnostic index has not been entirely established. It can provide a useful recording of patients' information processing, and indicate the severity of the clinical state and its possible evolution. It can also assist in determining what therapeutic approach to adopt. In the present review, the findings in the literature concerning interindividual variation in the P300 wave are first described; several variables significantly influence the amplitude and latency of this wave, such as age, gender, intelligence and personality. Following this, the relevance of the data in the literature on the clinical applications of P300 in psychopathology is examined, including the studies undertaken to obtain an objective diagnostic index for mental disorders and also those carried out to assess the problems concerning the interpretation of information connected with the mental pathologies examined. P300-associated findings on dementia, schizophrenia, depression, alcoholism, drug addiction, anxiety disorders (panic disorder, obsessive-compulsive disorder, and post-traumatic stress syndrome) and on personality disorders (schizoid, antisocial or borderline personality disorder) have been examined in detail.

Frontostriatal deficits in unipolar major depression

Recent accounts of major depression have tended to focus on dysfunction of frontothalamic-striatal reentrant circuits as a possible source of the disorder. Evidence of frontostriatal involvement in unipolar major depression from lesion and neuropsychological studies, and functional and structural imaging studies is examined. The high incidence of depressive symptomatology following left frontal and basal ganglia lesions implicate these as possible sites of dysfunction. Neuropsychological evidence indicates similar deficits in patients with major depression, perhaps with dorsolateral prefrontal deficits most prominent. Structural imaging studies report frontal and basal ganglia (BG) abnormalities particularly in cases of late-age onset depression. Resting state functional imaging studies show deficits in dorsolateral, anterior cingulate (medial frontal), and BG structures. Activation imaging studies show less consistent evidence of dorsolateral deficit, while anterior cingulate deficit is more consistently demonstrated. Variability in findings across studies may reflect differences between subtypes of depression and differences in methodology. Possible involvement of the BG in the psychomotor retardation of depression is examined. It is concluded that, while there is evidence of frontostriatal deficit in major depression, the exact nature of such deficits is uncertain. Issues such as component vs. system dysfunction need to be addressed.

Visual cognitive dysfunction in depression: an event-related potential study

The P3(00) event-related potentials (ERPs) elicited by visual stimuli in two visual tasks were assessed in depressed patients (12 patients with major depression and 11 patients with bipolar disorder) and compared with those of 20 age-matched normal controls. At remission, the ERPs from 18 of the depressed patients were again recorded. The visual oddball (VO) paradigm presented both target and standard visual stimuli and the simple visual (SV) paradigm presented a target but no standard visual stimulus. Subjects performed the VO task significantly less accurately than the SV task, as reflected by the behavioral measures (reaction-time and task accuracy). Depressed patients of the bipolar group showed longer P3 peak latency for the VO task and no change in P3 amplitude. No significant differences were found in any other ERP component between the groups. During remission, slowing RTs and reduced P3 peak latencies were observed for both major depression and bipolar disorder groups. Thus, the P3 ERP may be an index of the contribution of the slowed central processing to psychomotor retardation in clinically homogenous samples of depressive patients performing an appropriately demanding task.

Structural and functional abnormalities in elderly patients clinically recovered from early- and late-onset depression

BACKGROUND

Structural and functional brain changes have been described in elderly patients with unipolar affective disorder. Changes appear to be more marked in patients with late-onset depression, but the reversibility of such changes after clinical recovery is not known.

METHODS

Magnetic resonance imaging, electroencephalography (EEG), and cognitive tests were performed in 23 elderly patients (mean age 66.5 years) clinically recovered from major depression. Twelve had late-onset depression (first episode over 55 years of age); 11 had early onset (first episode before 50 years). EEG and cognitive testing were also performed on 15 control subjects.

RESULTS

Patients with late-onset depression had larger third and lateral ventricles, increased ventricular-brain ratio, and greater frequency and severity of subcortical white matter lesions than those with early onset. There was no difference between early- and late-onset patients in EEG and cognitive measures, but compared with controls patients showed significant changes in EEG evoked potentials and increased slow-wave activity, slowed reaction times, and global impairments in cognitive function.

CONCLUSIONS

These results suggest that structural changes are greater in patients with late-onset depression, and that EEG and cognitive impairments persist after recovery, regardless of age of onset of depression, and are independent of structural changes.

A preliminary profile of neuropsychological deficits associated with major depression

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 two standard deviations or more below the mean of controls. The neuropsychological deficits of 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 referred to. 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.

Heterogeneity of information-processing alterations according to dimensions of depression: an event-related potentials study

To identify alterations in elementary cognitive operations according to dimensions of depression, two stages of information processing, namely the response choice and the motor preparation stages, were explored using an event-related potential paradigm in two subgroups of depressed patients (retarded and blunted affect versus anxious-agitated and impulsive) compared to controls. Two results are common to all depressed patients: a slow encoding of stimuli (P1 wave) and a prolonged processing of stimulus-response compatibility (after P3b). This is compensated by a global velocity increase in stimulus evaluation or decision making (P3b) in anxious-agitated patients or, on the contrary, cumulated with its velocity decrease in retarded-blunted-affect patients. Such results could provide an explanation for the massive retardation observed in blunted-affect patients, contrary to anxious-agitated patients, whose normal reaction times may come from a very high energetical involvement at the P3b level. Results as a whole suggest that impairments in blunted-affect patients concern effort mechanisms, whereas those in anxious-agitated patients concern perceptual processes.

Suicidal behavior in depressive disorder: an event-related potential study

P300 and contingent negative variation (CNV) were recorded in depressive inpatients with and without history of suicide attempt. The results showed a significant reduction of P200, P300, and CNV and a significant increase of postimperative negative variation (PINV) in patients who had attempted suicide compared to patients with a negative history. Moreover, P300 amplitude was negatively related with the Suicidal Risk and the Hopelessness but not with the Hamilton scales. These results stress the need to differentiate clinical subgroups of patients to assess the psychophysiology of depression, and indicate that patients who attempted suicide exhibit lower cortical resources and poorer cortical performance than patients without history of suicide attempt.

Catecholaminergic function and P300 amplitude in major depressive disorder (P300 and catecholamines)

The neurobiology of P300 is still a subject of controversy. P300 amplitude appears to be modulated by multiple neurotransmitter systems, especially dopaminergic, noradrenergic as well as cholinergic and GABAergic. In this study, we investigated the relationship between P300 amplitude and catecholaminergic neurotransmission as assessed by the growth hormone (GH) response to clonidine and apomorphine challenges in 20 major depressive patients. Results showed a correlation of P300 amplitude with the apomorphine test (r = 0.54; P = 0.01), but not with the clonidine test (r = 0.22; NS). This study supports a role for dopamine in the neurobiological modulation of P300 amplitude.

[The influence of suicide risk and despondency on the amplitude of P300 in major depression]

P300 amplitude represents a useful tool to assess information processing in normal and psychopathological subjects. In depressive disorders, many studies have shown a decrease of P300 amplitude and an increase of its latency. However, functional significance of the P300 modifications remain unclear. The aim of the study was to assess the influence of suicidal risk and hopelessness on P300 amplitude among 40 depressive inpatients. The results showed significant relationships between P300 amplitude and suicidal risk (r = -0.68, p < 0.001) and with hopelessness (r = -0.76, p < 0.001). From a clinical point of view, P300 amplitude should be considered as a psychophysiological index of suicidal risk in major depressive disorder.

Differing patterns of electrodermal and finger pulse responsivity in schizophrenia and depression

Non-response of the autonomic orienting response (OR), as indexed jointly by deficient skin conductance (SCR) and finger pulse amplitude responding (FPAR), has been shown to occur with excessive frequency in the schizophrenic population. The present study is an attempt to replicate earlier evidence that SCR-OR and FPAR-OR, when measured in concert, could distinguish schizophrenic from depressed patients (Bernstein et al. 1988). This issue is critical of the question of diagnostic specificity of OR non-responding, since reduced SCR has been found repeatedly in depression as well as in schizophrenia. We examined SCR and FPAR concurrently in 69 schizophrenic, 45 depressed, and 67 normal subjects. SCR non-responding was more frequent in both schizophrenics and depressives than in normal controls, while only the schizophrenics displayed excessive FPAR non-responding. Moreover, among SCR non-responders, concordant OR non-responding--defined as non-responding indexed simultaneously in both the SCR and FPAR components--was most common in the schizophrenic sample. These findings support our previous conclusion that OR non-responding in depression, may have distinct peripheral origins. Our results also suggest that measuring multiple biochemically distinct components of the OR may be more sound methodologically than obtaining a single channel recording.

Lateralization of the Bereitschaftspotential to the left hemisphere in patients with major depression

Fourteen patients with major depression and 18 healthy subjects performed a Bereitschaftspotential (BP) paradigm, which required them to clench the right fist at self-paced intervals. The BP was calculated as the integrated negative amplitude from BP onset to movement onset. The latter was defined by recording the electromyogram (EMG) from the right forearm. To evaluate lateralization, the integrated BPs at C3, C4, P3, and P4 were analyzed. In depressives, a significant asymmetry of the BP to the left was found, whereas in normals the BP was nearly symmetrically distributed around the midline. Three patients were retested when clinically improved. At that time the asymmetry to the left hemisphere had nearly vanished. This asymmetry to the left hemisphere is interpreted as a cortical deactivation of the right cerebral hemisphere and seems to be a state marker of depression.

A study of P300 in melancholic depression--correlation with psychotic features

The relationship between delusions and hallucinations (psychotic features) in melancholic depression and auditory P300 was studied. Forty patients with melancholic depression as per DSM-III-R were studied, 20 of whom had hallucinations and/or delusions. The 20 patients of the two groups were individually matched on age, gender, sociodemographic variables, and psychopathology (except for psychotic features). Auditory P300 obtained by the "oddball paradigm" showed that those with hallucinations and/or delusions had a significantly smaller P3 amplitude. Significant correlations between "psychotic features" and P3 amplitude was found. Implications of these findings on research, classification, and management of depression have been outlined.

P300 amplitude in non-bipolar, melancholic depression

P300 event related potential (ERP) was recorded using the auditory 'oddball' paradigm in 17 melancholic, drug-free depressive patients and 22 normal controls. Repeat ERP recordings were obtained from 13 patients after recovery with ECT. Pretreatment P300 latencies were not different between patients and controls, nor did they change in the depressives following recovery. Pretreatment P300 amplitudes in depressives were smaller (P < 0.02) than in controls and negatively correlated with severity (P < 0.05). P300 amplitudes significantly increased in patients following recovery (P < 0.05) and normalized. P300 may be a state marker for melancholic depression.

Latencies of the P300 component of the auditory event-related potential in depression are related to the Bech-Rafaelsen Melancholia Scale but not to the Hamilton Rating Scale for Depression

The relationship between severity of depression and the P300 latency of auditory event-related potential was investigated in 36 patients with a major depressive episode according to DSM-III. Positive correlations were found between of the P300 latency and the total score of the Bech-Rafaelsen Melancholia Scale (BRMS), the 4 retardation items of the BRMS (motor, verbal, intellectual and emotional) and the item for lowered mood. In contrast, latencies were not associated with the scores of the Hamilton Rating Scale for Depression, which considers retardation to a lesser extent than the BRMS.

The late event related potentials CNV and PINV in normal and dyslexic subjects

The most prominent ERP to occur during intervals of preparation and anticipation is the contingent negative variation (CNV) or expectancy wave. The resolution of this wave is called the postimperative negative variation (PINV). The purpose of this study was to distinguish the characteristics of the CNV and the PINV in a group of children with reading disabilities or dyslexia and to compare them from a group of normal readers. Nine righthanded boys aged between 10-13 years with reading disabilities were studied. The children were matched with a group of nine normal readers. Four derivations were used: frontal, central, parietal and occipital zones, with reference to linked ears. Data were analyzed using multivariate procedures. Significant differences between groups in CNV amplitude and in PINV amplitude and latency at the left parietal site were observed. We discuss the participation of this zone and we consider processes like expectancy, attention and brain activity signal processing in the differences mentioned.

Attention impairment and psychomotor retardation in depressed patients: an event-related potential study

The cerebral event-related potentials (ERPs) and reaction times (RTs) of 8 drug-free depressed in-patients (mean age 58, with marked psychomotor retardation) were recorded during a dichotic listening and choice RT task and compared to those of 9 healthy, age-matched controls. The depressed showed significantly longer, more variable RTs than the controls and made more mistakes. Their ERPs for targets in the attended ear differed significantly from those of the controls by the small amplitude (or absence) of the N2 vertex component elicited by the controls in such a situation and by the presence in the same situation of a late frontal slow negativity (LFN) that did not show up in the grand average ERP of the control group. These results were discussed in terms of the two components of the processing negativity described by Näätänen (1982, 1985) and according to resource models of attention: whereas the controls would perform this easy task quickly thanks to quasi-automatic matching processes (reflected by the vertex N2), the depressed would need further effortful, controlled processing (reflected by the LFN) to perform the task.

Cortical evoked potentials and clinical rating scales as measures of depressive illness

Relationships between clinical ratings and cortical evoked potentials were examined before and during antidepressant drug treatment in 32 patients with major depressive disorder (DSM-III). Clinical rating scales included Hamilton Rating Scale for Depression, Beck Depression Inventory, Present State Examination (PSE) and Newcastle Scale. Evoked potentials included contingent negative variation (CNV), post-imperative negative variation (PINV) and auditory evoked potential (AEP) There were close correlations between all rating scales, and factor analysis produced only one component, suggesting that the common variance between them related to severity of depression. CNV magnitude before treatment correlated negatively with severity of depression regardless of diagnostic category. Depressed patients had a prominent PINV which persisted during antidepressant treatment. The amplitude of late components (N1P2) of the AEP was reduced strikingly in patients with a history of suicide attempts.

Electrophysiological changes elicited by auditory stimuli given a positive or negative value: a study comparing anhedonic with hedonic subjects

The present experiment investigates in 'normal' subjects the relationship between personality characteristics (anhedonia versus hedonia) and the influence of the affective value of acoustic stimuli (positive, negative, neutral) on various electrophysiological indices reflecting either tonic activation or phasic arousal (EEG power spectra, contingent negative variation: CNV, heart rate, skin potential responses: SPR) as well as on behavioural indices (reaction time: RT). Eighteen subjects were divided into two groups according to their scores at two self-rating questionnaires, the Chapman's Physical Anhedonia Scale (PAS) and the Beck-Weissman's Dysfunctional Attitude Scale (DAS) that quantifies cognitive distortions presumed to constitute high risk for depression: 9 with high scores at both scales formed the A group (Anhedonic-dysfunctional), 9 with low scores at both scales, the H group (Hedonic-adapted) The electrophysiological indices were recorded during 3 situations: the first one was a classical CNV paradigm with a motor reaction time task in which one of 3 tones of different pitch represented the warning stimulus S1; during the second, conditioning phase, two of these tones were associated with either a success (and reward) or a failure (and punishment) during a memory task in order to make them acquire either a positive or a negative affective value; the third situation consisted in the repeating of the first CNV paradigm in order to test the effect of the positive and the negative stimuli versus the neutral one on RTs and electrophysiological data. Significant between-group differences were found regarding tonic activation as well as phasic arousal indices from the very beginning of the experiment when all stimuli were neutral ones, the anhedonics exhibiting higher activation and arousal than the hedonics at the cortical (increased CNV amplitude, increased power in the beta frequency band), cardiovascular (higher heart rate habituating more slowly) and behavioural (faster RTs) levels. Significant between-group differences were also found concerning reactivity to affective stimuli during the third situation: both the orienting response (but only at the cortical level: early CNV) and the motor preparation processes (late CNV) were in the A group significantly less reactive to affective stimuli (especially to the positive one) than in the H group, in particular concerning the frontal (Fz) data.