Utility of the Work and Social Adjustment Scale (WSAS) in predicting long-term sick-leave in Danish patients with emotional disorders.

BACKGROUND: The Work and Social Adjustment Scale (WSAS) is a self-administered measure designed to assess the level of inability to function socially as a consequence of a defined problem or disorder. METHODS: A total of 230 patients with emotional disorders completed the Danish translation of the WSAS, measures of anxiety and depression, the Level of Personality Functioning Brief Form, the Personality Inventory for DSM-5 Short Form, and the World Health Organization Five-Item Well-Being Index (WHO-5). We conducted a confirmatory factor analysis of the previously suggested factor structure of the instrument. We furthermore evaluated the construct validity of the WSAS by means of its relationship with depression, anxiety, personality functioning, and overall well-being. Finally, we evaluated the utility of the WSAS to identify those on long-term sick-leave by conducting receiver operating characteristic (ROC) curves. RESULTS: The instrument had a poor to average fit with the previously reported single-factor structure, but a better fit to a modified single-factor structure. Cronbach's alpha and McDonald's omega showed good internal scale reliability (α = .79, ωtotal = .85). WSAS was positively correlated with measures of anxiety (r = .33), depression (r = .44), and personality functioning (r = .23 and r = .20), and negatively correlated with WHO-5 wellbeing (r = -.57). The optimal cut-off point in the ROC-analyses was 23, which yielded a sensitivity of 74% and a specificity of 55% in the prediction of sick-leave status. DISCUSSION: The Danish WSAS shows promising psychometric properties, but has limited external validity insofar as predicting long-term sick leave in psychiatric patients with emotional disorders.

Affectivity in danish patients with emotional disorders: assessing the validity of the Positive and Negative Affect Schedule (PANAS).

BACKGROUND: The Positive and Negative Affect Schedule (PANAS) was designed to measure trait positive affect (PA) and trait negative affect (NA). METHODS: The Danish PANAS was administered to outpatients with depression and anxiety disorders. Internal consistency was assessed using Cronbach's alpha and McDonald's omega and factorial structure was evaluated using confirmatory factor analysis (CFA). Convergent validity was evaluated by means of correlations with the negative affectivity and the detachment domain of the Personality Inventory for DSM-5 Short Form (PID-5-SF), the Hamilton Anxiety Rating Scale 6 (HARS-6) and the Hamilton Depression Rating Scale 6 (HDRS-6). RESULTS: PANAS Scores of 256 patients were analyzed. Cronbach's alpha and McDonald's omega showed good internal consistency for both the PA score (alpha = .84 and omega = .89) and the NA score (alpha = .86 and omega = .90). CFA analysis confirmed a structure with two factors corresponding to the PA and NA factors. PA was negatively correlated with the detachment domain of PID-5 (r = -.47), HARS-6 (r = -.15) and HDRS-6 (r = -.37). NA was positively correlated with PID-5-SF negative affectivity domain (r = .43), HARS-6 (r = .51) and HDRS-6 (r = .52). DISCUSSION: The Danish PANAS has promising internal consistency and construct validity, which are comparable to other studies of the instrument.

What is the effect of using collaborative assessment on symptomatology as an intervention in the treatment of mental illness? A systematic review and meta-analysis protocol.

BACKGROUND: Clinicians usually conduct diagnostic assessments in order to establish a diagnosis or to evaluate the effect of treatment. Two meta-analyses suggest that diagnostic assessment administered in collaboration with the patient and personalized feedback might have a therapeutic effect. METHODS: We aim to conduct a systematic review and meta-analysis of the effect on symptomatology when using assessment as a therapeutic intervention for patients with psychiatric illnesses. We will search in five relevant electronic databases. Two reviewers will independently select papers following pre-defined eligibility criteria, extract data, and assess the quality of included studies. Randomized controlled trials comparing the effect of psychological assessment with other psychotherapeutic interventions in populations of patients will be included in the meta-analysis. We will extract data on symptom-related outcomes, quality of life, dropout, and re-diagnosis and use meta-analysis techniques to compute the effect size of interventions using assessment as a psychotherapeutic intervention. The review will be conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Risk of bias will be assessed by using the Risk of Bias tool RoB 2.0 of the Cochrane Collaboration, and the certainty of the body of evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. DISCUSSION: THE RESULTS WILL BE ABLE TO INFORM CLINICIANS AND POLICYMAKERS ON THE EFFECT OF ASSESSMENT AND, DEPENDING ON THE RESULTS, COULD LEAD TO A RECOMMENDATION FOR MODIFIED ASSESSMENT PROCEDURES AND APPROACHES IN MENTAL HEALTH SERVICES. ULTIMATELY, IT MIGHT IMPROVE THE TREATMENT OUTCOME IN MENTAL HEALTH SERVICES.: SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021270567.

Interventions involving own treatment choice for people living with coexisting severe mental illness and type 1 or 2 diabetes: A scoping review.

AIM: The objective of this scoping review was to summarize, understand and provide an overview of the empirical literature on interventions involving own treatment choice for people with coexisting diabetes (type 1 and 2) and severe mental illness (SMI). METHODS: This scoping review undertook a systematic literature assessment. Searches were performed in MEDLINE, Embase, PsycINFO, Web of Science, CINAHL, the Cochrane Library and grey literature (OpenGrey, Google Scholar and Danish Health and Medicine Authority databases). Publications from 2000 to July 2020 were of interest. Studies were included if they involved the users' own choice of treatment. INCLUDED STUDIES: RCT, intervention, cohort and case-based studies. RESULTS: A total of 4320 articles were screened, of which nine were included. The review identified eight studies from the United States and one from Canada testing different interventions for people with SMI and diabetes (one diabetes education program, five randomized controlled trials, one retrospective cohort study, one naturalistic intervention program and one case vignette). The interventions described in the nine articles involved service users, the majority incorporated individualized healthcare plans, and all interventions were based on multidisciplinary teamwork. CONCLUSIONS: Research in the area is limited. Care management interventions tend to focus on a single condition, paradoxically excluding SMI during enrolment. Interventions aimed at people with both conditions often prioritize one condition treatment leading to an unbalanced care.

Transdiagnostic group CBT vs. standard group CBT for depression, social anxiety disorder and agoraphobia/panic disorder: Study protocol for a pragmatic, multicenter non-inferiority randomized controlled trial.

BACKGROUND: Transdiagnostic Cognitive Behavior Therapy (TCBT) manuals delivered in individual format have been reported to be just as effective as traditional diagnosis specific CBT manuals. We have translated and modified the "The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders" (UP-CBT) for group delivery in Mental Health Service (MHS), and shown effects comparable to traditional CBT in a naturalistic study. As the use of one manual instead of several diagnosis-specific manuals could simplify logistics, reduce waiting time, and increase therapist expertise compared to diagnosis specific CBT, we aim to test the relative efficacy of group UP-CBT and diagnosis specific group CBT. METHODS/DESIGN: The study is a partially blinded, pragmatic, non-inferiority, parallel, multi-center randomized controlled trial (RCT) of UP-CBT vs diagnosis specific CBT for Unipolar Depression, Social Anxiety Disorder and Agoraphobia/Panic Disorder. In total, 248 patients are recruited from three regional MHS centers across Denmark and included in two intervention arms. The primary outcome is patient-ratings of well-being (WHO Well-being Index, WHO-5), secondary outcomes include level of depressive and anxious symptoms, personality variables, emotion regulation, reflective functioning, and social adjustment. Assessments are conducted before and after therapy and at 6 months follow-up. Weekly patient-rated outcomes and group evaluations are collected for every session. Outcome assessors, blind to treatment allocation, will perform the observer-based symptom ratings, and fidelity assessors will monitor manual adherence. DISCUSSION: The current study will be the first RCT investigating the dissemination of the UP in a MHS setting, the UP delivered in groups, and with depressive patients included. Hence the results are expected to add substantially to the evidence base for rational group psychotherapy in MHS. The planned moderator and mediator analyses could spur new hypotheses about mechanisms of change in psychotherapy and the association between patient characteristics and treatment effect. TRIAL REGISTRATION: Clinicaltrials.gov NCT02954731 . Registered 25 October 2016.

Recovery-Oriented Practice in Mental Health Inpatient Settings: A Literature Review.

OBJECTIVE: Implementation of recovery-oriented practice has proven to be challenging, and little is known about the extent to which recovery-oriented principles are integrated into mental health inpatient settings. This review of the literature examined the extent to which a recovery-oriented approach is an integrated part of mental health inpatient settings. METHODS: A systematic search (2000-2014) identified quantitative and qualitative studies that made explicit reference to the concept of recovery and that were conducted in adult mental health inpatient settings or that used informants from such settings. The quality and relevance of the studies were assessed with the Critical Appraisal Skills Program, and a text-driven content analysis identified three organizing themes: definitions and understandings, current practice, and challenges. RESULTS: Eight studies from Canada, the United Kingdom, the United States, Australia, and Ireland were included. The results highlight the limited number of studies of recovery-oriented practice in mental health inpatient settings and the limited extent to which such an approach is integrated into these settings. Findings raise the question of whether recovery-oriented practice can or should be an approach used in these settings, which are primarily aimed at stabilization and symptom relief. CONCLUSIONS: Research is needed to clarify the concept of recovery and how it applies to mental health inpatient settings. The challenges to recovery-oriented practice posed by the current organization of such settings should be examined.

Cognitive behavioural therapy for ADHD in adults: systematic review and meta-analyses.

Systematically review and analyse the efficacy of CBT versus treatment as usual in adults with ADHD. The literature was systematically searched ending the 28 March 2014. Standardised mean differences (SMD) and 95% confidence intervals were calculated. CBT was efficacious in reducing symptoms of ADHD (SDM -1.0, 95% CI -1.5 to -0.5) when evaluated by the patients, but not when evaluated by a clinician. Symptoms of depression and anxiety were significantly reduced when self-reported (SMD -1.0, 95% CI -1.6 to -0.5 and -1.0, 95% CI -1.3 to -0.3, respectively) and evaluated by a clinician (SMD -0.9, 95% CI -1.7 to -0.2 and -0.9, 95% CI -1.6 to -0.1). The clinical global impression scores improved more in the group randomised to CBT (-1.0; 95% CI -1.6 to -0.4). CBT seems efficacious in some domains affecting adult patients with ADHD, but needs further evaluation.

Self-disorder and brain processing of proprioception in schizophrenia spectrum patients: a re-analysis.

BACKGROUND: Anomalies of self-awareness (self-disorders, SDs) are theorized to be basic to schizophrenia psychopathology. We have previously observed dysfunction of brain processing of proprioception in schizophrenia spectrum disorders (SZS). We hypothesized that SDs could be associated with abnormalities of early contralateral proprioceptive evoked oscillatory brain activity. METHODS: We investigated the association between proprioceptive evoked potential components and SDs in a re-analysis of data from a subsample (n = 12) of SZS patients who had previously been observed with deviant proprioceptive evoked potentials and interviewed with the Examination of Anomalous Self-Experience (EASE) scale. RESULTS: Higher EASE scores (i.e. increased SD) were associated with lower peak parietal gamma frequencies and higher peak beta amplitudes over frontal and parietal electrodes in the left hemisphere following right-hand proprioceptive stimulation. CONCLUSION: Disorders of self-awareness may be associated with dysfunction of early phases of somatosensory processing. The findings are potentially relevant to our understanding of the pathophysiology of schizophrenia, but further studies are needed.

Beneficial effect of brief intensive cognitive behavioural therapy-based psychiatric aftercare for early discharged non-psychotic patients.

INTRODUCTION: In Denmark, following psychiatric emergency admission, patients with depression, anxiety or personality disorders are discharged as early as possible due to pressure on psychiatric beds. However, the receiving out-patient units frequently have waiting time. The design of a brief, cognitive-based psychiatric aftercare service and the early treatment results are presented. MATERIAL AND METHODS: This was a descriptive study of symptom levels before and after the individual therapy part of a new aftercare programme. The initial new intensive aftercare consisted of psychiatric consultations, telephone outreach and individual cognitive behavioural therapy-based therapy twice a week, in total five times. Focus was on collaborative goal setting and next-of-kin participation. Self-ratings (WHO-5 Well-Being Scale (WHO-5); Becks Depression Inventory-II (BDI)) were obtained at the first day and at end of individual therapy. RESULTS: The self-ratings at discharge showed a high BDI rating in the patient sample (mean = 32.0 (standard deviation (SD) = 11.9; n = 105)), and much lower well-being at discharge than previously seen in a comparable Danish setting (mean WHO-5 at onset = 5.6 (SD = 4.8; n = 102)). Ratings improved by the end of the individual therapy (i.e. WHO-5 = 8.3 (SD = 5.6; n = 102); BDI = 26.1 (SD = 12.3; n = 105)). CONCLUSION: Symptom reduction was evident in the first period after discharge, and the patients were satisfied with the contents and format of the service. However, the results are preliminary as we lack data from a comparable patient group receiving no treatment or treatment as usual. FUNDING: not relevant. TRIAL REGISTRATION: Danish Data Protection Agency, The Capital Region 2007-58-0015.

Closed eyes condition increases auditory brain responses in schizophrenia.

The 40-Hz auditory steady-state responses (ASSRs) of 14 medicated schizophrenic patients were recorded in eyes-open and eyes-closed conditions as previously done in healthy volunteers. Patients show significantly increased precision of the evoked response with eyes closed, and a significant increase of broad-band noise activity when eyes are open.

P50 potential-associated gamma band activity: modulation by distraction.

We aimed to evaluate the effect of changing attentional demands towards stimulation in healthy subjects on P50 potential-related high-frequency beta and gamma oscillatory responses, P50 and N100 peak amplitudes and their gating measures. There are no data showing effect of attention on P50 potential-related beta and gamma oscillatory responses and previous results of attention effects on P50 and N100 amplitudes and gating measures are inconclusive. Nevertheless the variation in the level of attention may be a source of variance in the recordings as well as it may provide additional information about the pathology under study. Nine healthy volunteers participated in the study. A standard paired stimuli auditory P50 potential paradigm was applied. Four stimulation conditions were selected: focused attention (stimuli pair counting), unfocused attention (sitting with open eyes), easy distraction (reading a magazine article), and difficult distraction (searching for Landolt rings with appropriate gap orientation). Time-frequency responses to both S1 and S2 were evaluated in slow beta (13-16 Hz, 45-175 ms window); fast beta (20-30 Hz, 45-105 ms window) and gamma (32-46 Hz, 45-65 ms window) ranges. P50 and N100 peak amplitudes in response to both S1 and S2 and their ratio were evaluated. The phase-locked P50 potential-associated gamma activity was attenuated during distraction tasks as compared to focused attention and an unfocused attention condition. The amplitudes and gating measures of P50 and N100 waves and beta activity were not sensitive to the competing distraction task performance. The use of a distraction task is not favorable when phase-locked gamma range activity is a key interest in auditory potential studies.

Proprioceptive information processing in schizophrenia.

This doctoral thesis focuses on brain activity in response to proprioceptive stimulation in schizophrenia. The works encompass methodological developments substantiated by investigations of healthy volunteers and two clinical studies of schizophrenia spectrum patients. American psychiatrist Sandor Rado (1890-1972) suggested that one of two un-reducible deficits in schizophrenia was a disorder of proprioception. Exploration of proprioceptive information processing is possible through the measurement of evoked and event related potentials. Event related EEG can be analyzed as conventional time-series averages or as oscillatory averages transformed into the frequency domain. Gamma activity evoked by electricity or by another type of somatosensory stimulus has not been reported before in schizophrenia. Gamma activity is considered to be a manifestation of perceptual integration. A new load stimulus was constructed that stimulated the proprioceptive dimension of recognition of applied force. This load stimulus was tested both in simple and several types of more complex stimulus paradigms, with and without tasks, in total in 66 healthy volunteers. The evoked potential (EP) resulting from the load stimulus was named the proprioceptive EP. The later components of the proprioceptive EP (> 150 ms) were modulated similarly to previously reported electrical somatosensory EPs by repetition and cognitive task. The earlier activity was further investigated through decomposition of the time-frequency transformed data by a new non-negative matrix analysis, and previous research and visual inspection validated these results. Several time-frequency components emerged in the proprioceptive EP. The contra-lateral parietal gamma component (60-70 ms; 30-41 Hz) had not previously been described in the somatosensory modality without electrical stimulation. The parietal beta component (87-103 ms; 19-22 Hz) was increased when the proprioceptive stimulus appeared in a predictable sequence in several runs of recording. Although the experimental paradigm had inherent confounders, it was suggested that the increase observed in the predictable situation, in healthy subjects, was due to priming of the somatosensory cortex through top-down modulation. The proprioceptive EP was investigated in two different samples of a total of 30 schizophrenia spectrum patients. The left contra-lateral parietal cortical activity 60-120 ms following the load stimulus was affected in both samples. In the first experiment a delay was observed and in the second experiment diminished amplitude and trial-to-trial phase consistency of high frequency (18-45 Hz) activity. Both effects were interpreted as a consequence of diminished precision of activation of the left somatosensory cortex and it was suggested to be in accordance with two theories of schizophrenic information processing: the theory of deficiency of corollary discharge and the theory of weakening of the influence of past regularities. No gating deficiency was observed and the imprecision and amplitude attenuation was not a general phenomenon across the entire brain response. Summing up, in support of Rado's hypothesis, schizophrenia spectrum patients demonstrated abnormalities in proprioceptive information processing. Future work needs to extend the findings in larger un-medicated, non-chronic, patient samples and investigate the connection between schizophrenic symptoms, perception and attenuation of the proprioceptive EP.

The level of arousal modulates P50 peak amplitude.

We aimed to evaluate the effect of arousal level in healthy subjects on P50 potential, as the variation in the level of arousal may be a source of variance in the recordings as well as it may provide additional information about the pathology under study. Eleven healthy volunteers participated in the study. A standard auditory P50 potential paradigm was applied. Two stimulation conditions were selected: eyes-open, i.e., high arousal level condition and eyes-closed, i.e., low arousal level condition. P50 component amplitudes in response to both the first (S1) and second stimulus (S2) of the pair, their ratio and difference were evaluated. P50 amplitude in response to S1 was significantly higher during the low arousal closed eyes condition as compared to high arousal open eyes condition. There was no P50 amplitude difference in response to S2 and no arousal effect on gating measures. This prompts for more careful evaluation of patients' arousal level when performing P50 studies and interpreting the results.

Distraction task rather than focal attention modulates gamma activity associated with auditory steady-state responses (ASSRs).

OBJECTIVE: To explore the modulation of auditory steady-state response (ASSR) by experimental tasks, differing in attentional focus and arousal level. METHODS: 20 Hz and 40 Hz click trains were used to elicit ASSRs. Experiment 1 consisted of two runs of closed eyes and two runs of open eyes. Experiment 2 consisted of six tasks: counting 20 Hz and 40 Hz stimuli, sitting with closed and open eyes, reading an article, and performing a search task. Phase locking factor, evoked amplitude and total intensity were decomposed by non-negative multi-way factorization. RESULTS: The total intensity of 40 Hz ASSR was enhanced during closed eyes condition in comparison to the open eyes condition. The evoked amplitude and phase locking factor of 40 Hz ASSR were attenuated during distraction, while there were no differences between attention to stimulation and no task. 20 Hz ASSR and 20 Hz ASSR-related 40 Hz activity were not modulated by the tasks. CONCLUSIONS: The phase-locked measures of 40 Hz ASSR are attenuated when attention to the stimulation is low, i.e. the subject is effortfully focused on the competitive "distraction" task performance. Lower arousal level increases the total intensity of 40 Hz ASSRs. SIGNIFICANCE: Improvements of the practical use of ASSRs are suggested: a careful monitoring for arousal fluctuations during ASSR recordings should be performed; when ASSRs are applied to investigate the ability to generate high frequency cortical activity a "distraction" task is not favorable.

Two discrete components of the 20 Hz steady-state response are distinguished through the modulation of activation level.

OBJECTIVE: To investigate the modulation of amplitude and phase precision of the auditory steady-state response (SSR) to 20 Hz stimulation in two conditions varying in the level of activation. METHODS: Click stimuli (20 Hz) were applied while subjects were sitting upright silently reading a book of interest (high activation level) and while subjects were sitting in a reclined position with eyes closed and the lights turned off (low activation level). Sixty-one channel EEG data was wavelet transformed, the amplitude and phase precision measures extracted and decomposed by the multi-subject non-negative multi-way factorization (NMWF). RESULTS: The NMWF decomposition of amplitude and phase precision measures resulted in the observation of two distinct components: a component at the frequency of stimulation--20 Hz SSR and a component emerging at 40 Hz--20 Hz SSR-related 40 Hz activity. Modulation by the activation level was observed only for 20 Hz SSR-related 40 Hz activity as increased amplitude and phase precision during low activation level. No such effects were observed for 20 Hz SSR. CONCLUSION: The discrete components of the 20 Hz SSR are distinguished through modulation of activation level, 20 Hz SSR-related 40 Hz being higher in low activation state. SIGNIFICANCE: The biological modulation of 20 Hz SSR-related 40 Hz activity by the level of activation points to a physiological nature of this activity beyond a mere periodic effect in relation to the 20 Hz activity.

Regularity increases middle latency evoked and late induced beta brain response following proprioceptive stimulation.

Focal attention increases the middle-latency amplitude of somatosensory evoked potentials. Previously this effect has been suggested to be due to increased readiness in somatosensory cortex. Presently, we examine whether regularity of stimulus occurrence increases the proprioceptive evoked response as an indication of increased readiness. This is achieved through detailed analysis of both evoked and induced responses in the time-frequency domain. Electroencephalography in a 64 channels montage was recorded in fourteen healthy subjects. Two paradigms were explored: A Regular alternation between hand of presentation and a Random sequence of hand of presentation. The ERPWAVELAB toolbox was used for decomposition of the wavelet transformed data (7 to 47 Hz, -300 to +1500 ms)" yielding the evoked amplitude (AvWT) and inter-trial phase coherence as well as the increase of non-time-locked activity (Induced). After initial exploration of the AvWT and Induced collapsed files of all subjects using two-way factor analyses (Non-Negative Matrix Factorization), further data decomposition was performed in restricted windows of interest (WOI). Main effects of side of stimulation, onset or offset, regularity and habituation on the evoked and induced activity are described for each WOI. The Regular paradigm evoked more activity than Random in the fast beta range (18-28 Hz) (mean: normalized amplitude 0.38 at 90 ms and 20.9 Hz) including increased phase precision. The findings confirm the possibility of modulation of middle-latency activity by regularity and suggest that this is due to facilitation of activity in secondary somatosensory cortices. Future studies need to examine whether the increased amplitude is associated with increased perceptual acuity.

Algorithms for sparse nonnegative Tucker decompositions.

There is a increasing interest in analysis of large-scale multiway data. The concept of multiway data refers to arrays of data with more than two dimensions, that is, taking the form of tensors. To analyze such data, decomposition techniques are widely used. The two most common decompositions for tensors are the Tucker model and the more restricted PARAFAC model. Both models can be viewed as generalizations of the regular factor analysis to data of more than two modalities. Nonnegative matrix factorization (NMF), in conjunction with sparse coding, has recently been given much attention due to its part-based and easy interpretable representation. While NMF has been extended to the PARAFAC model, no such attempt has been done to extend NMF to the Tucker model. However, if the tensor data analyzed are nonnegative, it may well be relevant to consider purely additive (i.e., nonnegative) Tucker decompositions). To reduce ambiguities of this type of decomposition, we develop updates that can impose sparseness in any combination of modalities, hence, proposed algorithms for sparse nonnegative Tucker decompositions (SN-TUCKER). We demonstrate how the proposed algorithms are superior to existing algorithms for Tucker decompositions when the data and interactions can be considered nonnegative. We further illustrate how sparse coding can help identify what model (PARAFAC or Tucker) is more appropriate for the data as well as to select the number of components by turning off excess components. The algorithms for SN-TUCKER can be downloaded from Mørup (2007).

The diagnostic status of first-rank symptoms.

OBJECTIVE: In the International Statistical Classification of Diseases, Tenth Revision(ICD-10) and Diagnostic and Statistical Manual of Mental Disorder, Third and Fourth Edition(DSM-III-IV), the presence of one of Schneider "first-rank symptoms" (FRS) is symptomatically sufficient for the schizophrenia diagnosis. Yet, it has been claimed that FRS may also be found in the nonschizophrenic conditions, and therefore, they are not specific or diagnostic for schizophrenia. This review was made to clarify the issue of diagnostic specificity. METHODS: (1) A critical review of FRS studies published in English between 1970 and 2005. (2) A highlight of the 5 most frequently cited studies identified in the Web of Science. (3) Theoretical implications of the epistemological issues of FRS. RESULTS: The reviewed studies do not allow for either a reconfirmation or a rejection of Schneider's claims about FRS. The sources of disagreement between the studies are (1) including or excluding acute patients with potential degradation of consciousness; (2) assessing or not the phenomenological context; (3) assessing patients in different stages of their illness evolution; and (4) differential emphasis on mood symptoms and history of psychiatric symptoms. CONCLUSION: Both DSM-IV and ICD-10 emphasize FRS to a degree that is not supported by the empirical evidence. Until the status of FRS is clarified in depth, we suggest that the FRS, as these are currently defined, should be de-emphasized in the next revisions of our diagnostic systems. Future studies aiming at validation of FRS as diagnostic features need to apply a phenomenological perspective and include a homogenous group of patients across a wide spectrum of diagnoses.

The amplitude and phase precision of 40 Hz auditory steady-state response depend on the level of arousal.

The aim of this study was to investigate, in healthy subjects, the modulation of amplitude and phase precision of the auditory steady-state response (ASSR) to 40 Hz stimulation in two resting conditions varying in the level of arousal. Previously, ASSR measures have shown to be affected by the level of arousal, but the findings are somewhat controversial. Generally, ASSR is diminished in sleep but it may be increased in drowsiness. Besides, ASSR reduction has been observed in schizophrenia. However, schizophrenic patients are known to have a disturbance of arousal level, what makes it pertinent to know the effects of fluctuations in arousal on passive response to gamma-range stimulation. In nine healthy volunteers trains of 40 Hz click stimuli were applied during two conditions: in the "high arousal" condition subjects were sitting upright silently reading a book of interest; in the "low arousal" condition subjects were sitting in a reclined position with eyes closed and the lights turned off. The 64-channel EEG data was wavelet transformed and the amplitude and phase precision of the wavelet transformed evoked potential were decomposed by the recently proposed multi-subject non-negative multi-way factorization (NMWF) (Morup et al. in J Neurosci Methods 161:361-368, 2007). The estimates of these measures were subjected to statistical analysis. The amplitude and phase precision of the ASSR were significantly larger during the low arousal state compared to the high arousal condition. The modulation of ASSR amplitude and phase precision by differences in the arousal level during recording warrants caution when investigating oscillatory brain activity and interpreting the findings of reduced ASSR in schizophrenia. It also emphasizes the necessity of standardized recording procedures and monitoring the level of arousal during ASSR testing.

Proprioceptive evoked gamma oscillations.

A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure of precision of evoked oscillations. The window of interest was 25-75 Hz and 0-200 ms. ITPC maxima were determined by visual inspection and these results were compared to results of multi-way factor analyses. The predicted 40 Hz activity was observed 60 ms after stimulus onset in the parietal region contralateral to stimulus side and additionally an unexpected 20 Hz activity was observed slightly lateralized in the frontal central region. The gamma phase locking may be a manifestation of early somatosensory feature integration. The analyses suggest that the high frequency activity consists of two distinct underlying oscillatory processes, in need of further investigation.