A case-matched study of neurophysiological correlates to attention/working memory in people with somatic hypervigilance.

OBJECTIVE: Somatic hypervigilance describes a clinical presentation in which people report more, and more intense, bodily sensations than is usual. Most explanations of somatic hypervigilance implicate altered information processing, but strong empirical data are lacking. Attention and working memory are critical for information processing, and we aimed to evaluate brain activity during attention/working memory tasks in people with and without somatic hypervigilance. METHOD: Data from 173 people with somatic hypervigilance and 173 controls matched for age, gender, handedness, and years of education were analyzed. Event-related potential (ERP) data, extracted from the continuous electroencephalograph recordings obtained during performance of the Auditory Oddball task, and the Two In A Row (TIAR) task, for N1, P2, N2, and P3, were used in the analysis. Between-group differences for P3 amplitude and N2 amplitude and latency were assessed with two-tailed independent t tests. Between-group differences for N1 and P2 amplitude and latency were assessed using mixed, repeated measures analyses of variance (ANOVAs) with group and Group × Site factors. Linear regression analysis investigated the relationship between anxiety and depression and any outcomes of significance. RESULTS: People with somatic hypervigilance showed smaller P3 amplitudes-Auditory Oddball task: t(285) = 2.32, 95% confidence interval, CI [3.48, 4.47], p = .026, d = 0.27; Two-In-A-Row (TIAR) task: t(334) = 2.23, 95% CI [2.20; 3.95], p = .021, d = 0.24-than case-matched controls. N2 amplitude was also smaller in people with somatic hypervigilance-TIAR task: t(318) = 2.58, 95% CI [0.33, 2.47], p = .010, d = 0.29-than in case-matched controls. Neither depression nor anxiety was significantly associated with any outcome. CONCLUSION: People with somatic hypervigilance demonstrated an event-related potential response to attention/working memory tasks that is consistent with altered information processing.

The TWIN-E project in emotional wellbeing: study protocol and preliminary heritability results across four MRI and DTI measures.

Despite the significant advancements being made in the neurogenetics for mental health, the identification and validation of potential endophenotype markers of risk and resilience remain to be confirmed. The TWIN-E study (The Twin study in Wellbeing using Integrative Neuroscience of Emotion) aims to validate endophenotype markers of mental health across cognitive, brain, and autonomic measures by testing the heritability, clinical plausibility, and reliability of each of these measures in a large adult twin cohort. The specific gene and environmental mechanisms that moderate prospective links between endophenotype-phenotype markers and the final outcome of wellbeing will also be identified. TWIN-E is a national prospective study with three phases: I) baseline testing on a battery of online questionnaires and cognitive tasks, and EEG, MRI, and autonomic testing; II) 12-month follow-up testing on the online assessments; and III) randomized controlled trial of brain training. Minimum target numbers include 1,500 male/female twins (18-65 years) for the online assessments (Phase I and II), 300 twins for the EEG testing component, and 244 twins for the MRI testing component. For Phase III, each twin out of the pair will be randomized to either the treatment or waitlist control group to test the effects of brain training on mental health over a 30-day period, and to confirm the gene-environment and endophenotype contributions to treatment response. Preliminary heritability results are provided for the first 50% of the MRI subgroup (n = 142) for the grey matter volume, thickness, and surface area measures, and white matter diffuse tensor imaging fractional anisotropy.

An integrative assessment of brain and body function 'at rest' in panic disorder: a combined quantitative EEG/autonomic function study.

We conducted a quantitative electroencephalographic (QEEG) and autonomic assessment of panic disorder (PD). The study samples comprised 52 individuals meeting DSM-IV criteria for PD (with or without agoraphobia) and 104 age-, gender-, and handedness-matched controls. EEG data were acquired from 16 scalp sites during resting eyes-open (REO) and eyes-closed (REC) conditions, and spectral power was assessed within 4 frequency bands: theta, alpha-1, alpha-2, and beta. The main findings were an overall reduction of spectral power in PD, compared to controls (Group main effect, p=.011), which was most apparent during REC (Group Condition interaction, p=.014), and within the alpha-1 frequency band (8-11 Hz; Group Band interaction, p=.014). Alpha-1 desynchronization occurs in response to increases in non-specific information processing, and aspects of attention such as alertness. Other findings were region-specific alterations of spectral power at frontal and temporal scalp sites, including a frontal alpha-1 asymmetry (R

Event-related potential and autonomic signs of maladaptive information processing during an auditory oddball task in panic disorder.

Various empirical data suggest that individuals with Panic Disorder (PD) fail to appropriately assign significance to sensory stimuli within the internal and external milieu, including those stimuli which are patently threat-neutral. The failure to appropriately discriminate 'signal' stimuli from among 'noise' signals [Gordon, E., Liddell, B.J., Brown, K.J., Bryant, R., Clark, C.R., Das, P., et al. 2007. Integrating objective gene-brain-behavior markers of psychiatric disorders. J. Integr. Neurosci. 6, 1-34.] results in disturbances of information processing and attentional deployment, which manifests across multiple levels of functioning (e.g., brain, behaviour, autonomic). The present event-related potential (ERP) study, therefore, investigated attentive information processing in PD, using a standard two-tone auditory oddball paradigm, to assess patients' response to infrequent 'target' tones (i.e., signals) and frequent 'non-target' tones (i.e., noise). Simultaneously-recorded autonomic data provided converging measures of the concomitants of disordered information processing. PD patients (n=50) showed increased N1 amplitude to frequent non-target tones and reduced P3 amplitude to infrequent targets, compared to matched controls (n=98). There were no between-group differences for N1 targets, N2 or P2. Patients additionally showed increased heart rate, fewer spontaneous skin conductance responses (trend) to significant stimuli, and reduced P3 latency compared to controls, although the latter result was accounted for by patients who frequently experienced depersonalization and/or derealisation during panic. Patients showed several disturbances of attentive information processing in a simple auditory discrimination task: Increased N1 to repeated stimuli suggests impaired stimulus filtering, whereas reduced P3 amplitude and latency represent the under-allocation of neural resources for infrequent, goal-relevant stimuli, and their increased speed of processing, respectively. These disturbances likely contribute to patients' aversive outcomes in stimulus-rich environments.