Hemispheric functional imbalance in a sub-clinical obsessive-compulsive sample assessed by the Continuous Performance Test, Identical Pairs version

Reduced Interhemispheric Functional Connectivity in Obsessive-Compulsive Disorder Patients

Background: Neuroimaging studies have shown that the high synchrony of spontaneous neural activity in the homotopic regions between hemispheres is an important functional structural feature of normal human brains, and this feature is abnormal in the patients with various mental disorders. However, little is known about this feature in obsessive-compulsive disorder (OCD). This study aimed to further analyze the underlying neural mechanisms of OCD and to explore whether clinical characteristics are correlated with the alerted homotopic connectivity in patients with OCD. Methods: Using voxel-mirrored homotopic connectivity (VMHC) during resting state, we compared 46 OCD patients and 46 healthy controls (HCs) matched for age, gender, and education level. A partial correlation analysis was used to investigate the relationship between altered VMHC and clinical characteristics in patients with OCD. Results: Patients with OCD showed lower VMHC than HCs in fusiform gyrus/inferior occipital gyrus, lingual gyrus, postcentral gyrus/precentral gyrus, putamen, and orbital frontal gyrus. A significant positive correlation was observed between altered VMHC in the angular gyrus/middle occipital gyrus and illness duration in patients. Conclusions: Interhemispheric functional imbalance may be an essential aspect of the pathophysiological mechanism of OCD, which is reflected not only in the cortico-striato-thalamo-cortical (CSTC) loop but also elsewhere in the brain.

A computerized neuropsychological evaluation of cognitive functions in a subclinical obsessive-compulsive sample

BACKGROUND AND OBJECTIVES

Ample research in obsessive-compulsive disorder (OCD) reveals a moderate degree of underperformance on various neuropsychological tasks. Less is known about neuropsychological function in subclinical obsessive-compulsive (OC) samples. Most analogue OCD studies did not use a comprehensive neuropsychological battery and none utilized a fully computerized battery. To fill this gap in the literature, the present study aimed at assessing cognitive functions in a subclinical OC sample using a validated computerized neuropsychological battery.

METHODS

Initially, a sample of 165 students completed the Obsessive-Compulsive Inventory-Revised (OCI-R). Using a psychometrically valid methodology, a high OC (HOC, n = 29) and low OC (LOC, n = 29) groups were selected based on scores in the upper and lower quartiles on the OCI-R. The two groups completed the NeuroTrax computerized neuropsychological battery and clinical questionnaires.

RESULTS

Although the HOC group underperformed on most outcome measures, controlling for state-anxiety and depression symptoms, no significant differences were found on major domains (i.e., memory, attention, executive functions, processing speed, visuospatial functions, verbal functions, and motor skills), and subdomains. Normalized scores, produced using population norms, indicated that both groups performed within the normative range.

LIMITATIONS

Not all neuropsychological subdomains were assessed.

CONCLUSIONS

Results are consistent with the general picture in analogue OC samples, and may be more reliable than paper-pencil testing, given that a full computerized neuropsychological battery minimizes examiner-examinee interactions, and increases timing accuracy. In sum, analogue OC samples, characterized by equivalent symptom severity but high functioning compared to OCD samples, do not present with cognitive deficits.

The Sensitivity of Three Versions of the Padua Inventory to Measuring Treatment Outcome and Their Relationship to the Yale-Brown Obsessive Compulsive Scale

The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and different versions of the Padua Inventory (PI) are frequently used instruments to measure symptoms of obsessive-compulsive disorder (OCD). However, little is known of how these different versions of the PI compare to each other in their sensitivity to measuring treatment outcome, and there is currently no adequate explanation to account for the weak relationships between self-report measures and the Y-BOCS. This study aimed to investigate the sensitivity of these measures to treatment outcome, and to examine whether differences in how they measure symptom severity can explain the weak relationships. Hypotheses were: (1) the Y-BOCS would be significantly more sensitive to measuring treatment outcome than the PI versions; (2) correlations between the measures would be significantly stronger for change scores as compared to relations measured at a single point in time; (3) weak relationships can be explained by the PI measuring symptom severity based on content and the Y-BOCS measuring symptoms, independent of content. Results showed that the Y-BOCS was significantly more sensitive to measuring treatment outcome than the PI versions, while differences between the questionnaires in which severity is measured can provide a partial account for why weak relations are observed between these measures.

Prefrontal tDCS and sertraline in obsessive compulsive disorder: a case report and review of the literature

Obsessive-compulsive (OC) disorder is a disabling disorder resulting in tremendous individual and social burden. It has a large overlap with depression and anxiety disorders and shows treatment resistance in a relevant proportion of patients. Since a couple of years, different noninvasive brain stimulation methods have been investigated to improve OC symptoms. The application of transcranial direct current stimulation (tDCS) has shown inconsistent results which can probably be attributed to a lack in randomized controlled trials with adequate sample size. Anodal stimulation of pre-supplementary motor areas has shown promising results, and there is also sparse data on orbitofrontal and prefrontal stimulation. Here, we provide the first report on a patient with treatment-refractory OC disorder treated with sertraline and an enhanced prefrontal tDCS protocol (twice per day, 10 days) with a classic left-anodal/right cathodal montage, experiencing a 22% reduction of OC symptoms as well as reduction in depression (-10%) and anxiety symptoms (-21%). Due to multifactorial origin of OC disorder and the variety of brain circuits involved, there are probably multiple approaches for brain stimulation regarding site, polarity, and frequency to be assessed in future studies.

Are obsessive-compulsive symptoms impulsive, compulsive or both?

BACKGROUND

The relationships between obsessive-compulsive symptoms and distinct forms of impulsivity and compulsivity are unclear. Such examination would be relevant in terms of how best to classify psychiatric disorders and in understanding candidate 'traits' that extend across a continuum between normalcy and clinical disorders.

METHOD

515 young adults (aged 18-29years) completed the Padua Inventory and undertook detailed clinical and neurocognitive assessments. Relationships between obsessive-compulsive symptoms and distinct types of impulsivity and compulsivity were evaluated using linear regression modeling.

RESULTS

Obsessive-Compulsive symptoms were significantly predicted by female gender, lower quality of life, psychiatric disorders in general (but not impulse control disorders), and worse extra-dimensional set-shifting. Obsessive-Compulsive symptoms were not significantly predicted by alcohol/nicotine consumption, stop-signal reaction times, or decision-making abilities.

CONCLUSION

These data indicate that obsessive-compulsive symptoms are more related to certain forms of compulsivity than to impulsivity. These findings have important implications for diagnostic conceptualizations and neurobiological models.

Response inhibition in a subclinical obsessive-compulsive sample

BACKGROUND AND OBJECTIVES

Inconsistent findings across studies challenge the viability of response inhibition (RI) as an endophenotype of obsessive-compulsive disorder (OCD). Contemporary conceptualization of endophenotypes in psychiatric disorders suggests that these markers vary continuously in the general population, highlighting the importance of analogue sample research. Although neuropsychological functions have been studied in subclinical obsessive-compulsive (OC) samples, no study to date had examined RI in the context of the go/no-go paradigm.

METHODS

A subclinical OC sample (HOC; n = 27) and a low OC symptoms control sample (LOC; n = 25), as determined by the Obsessive-Compulsive Inventory-Revised, completed a go/no-go task and clinical questionnaires.

RESULTS

The groups did not differ on age, gender, or state anxiety. Controlling for depressive severity, the HOC group made significantly more commission errors and exhibited larger response time variability on the go/no-go task. However, standardized scores produced using population norms revealed that the HOC group performed within normative range.

LIMITATIONS

This study used a non-clinical sample and no structured clinical screening was performed.

CONCLUSIONS

Compared to LOC participants, a psychometrically-defined subclinical OC sample exhibited deficient RI and sustained attention. However, when raw scores were converted to age and education adjusted standardized scores according to the test's population norms, the HOC group task performance was in the normative range. These results, are in line with findings in OCD samples, suggesting that moderate degree of RI deficiencies is associated with the presence of OC symptomatology regardless of clinical status. However, the conceptualization of RI underperformance as an OCD disorder-specific impairment, remains controversial.

Modulation of affective symptoms and resting state activity by brain stimulation in a treatment-resistant case of obsessive-compulsive disorder

The effect of transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) on psychopathological symptoms and resting state brain activity was assessed in a patient with obsessive-compulsive disorder (OCD). tDCS and rTMS had no effect on OC symptoms. tDCS, however, improved depression and anxiety. Functional magnetic resonance imaging at baseline showed an interhemispheric asymmetry with hyperactivation of the left and hypoactivation of the right anterior neural circuits. A reduction of interhemispheric imbalance was detected after tDCS but not after rTMS. tDCS seems to be more effective than rTMS in restoring interhemispheric imbalance and improving anxiety and depression in OCD.

Cognitive performance in a subclinical obsessive-compulsive sample 1: cognitive functions

Individuals who are not clinically diagnosed with obsessive-compulsive disorder (OCD) but still display obsessive-compulsive (OC) tendencies may show cognitive impairments. The present study investigated whether there are subgroups within a healthy group showing characteristic cognitive and emotional performance levels similar to those found in OCD patients and whether they differ from OCD subgroups regarding performance levels. Of interest are those cases showing subclinical symptomatology. The results revealed no impairments in the subclinical OC participants on the neuropsychological tasks, while evidence suggests that there exist high and low scores on two standardised clinical instruments (Yale-Brown Obsessive Compulsive Scale and Cognitive Assessment Instrument of Obsessions and Compulsions) in a healthy sample. OC symptoms may diminish the quality of life and prolong sustainable return to work. It may be that occupational rehabilitation programmes are more effective in rectifying subclinical OC tendencies compared to the often complex symptoms of diagnosed OCD patients. The relationship between cognitive style and subclinical OC symptoms is discussed in terms of how materials and information might be processed. Although subclinical OC tendencies would not seem to constitute a diagnosis of OCD, the quality of treatment programmes such as cognitive behavioural therapy can be improved based on the current investigation.

Clinical correlates of caudate volume in drug-naïve adult patients with obsessive-compulsive disorder

The neurobiological basis of obsessive-compulsive disorder (OCD) has been theorized to reflect a dysfunction of cortico-striato-thalamo-cortical circuits, of which the caudate nucleus forms a critical component. However, structural imaging studies of the caudate in OCD are relatively scarce. To ascertain the clinical correlates of caudate volume in OCD, we report magnetic resonance imaging findings in a large sample of drug-naïve OCD patients in comparison with group-matched healthy controls. In this study, caudate volume was measured in coronal magnetic resonance brain images (high resolution 1-mm slice thickness) of 49 DSM-IV OCD patients and compared with that of 39 matched healthy controls. The caudate volume was measured separately for the head and body of the caudate. Analysis of covariance (ANCOVA) did not reveal significant differences in caudate volume between OCD patients and controls (whole group), with age, sex and intracranial volume as covariates. However, on examining the sexual dimorphism in the volume differences, male patients compared to male controls had significantly larger right caudate volume. The volume of the left caudate body showed a significant negative correlation with the total severity score on the Yale-Brown Obsessive-Compulsive Scale (YBOCS) on partial correlation analysis. Our study failed to show significant differences in caudate volumes between OCD patients and controls. However, it demonstrated a robust relationship between volume of the left caudate body and the severity of OCD. Additionally, there was a sexual dimorphism in caudate volume in OCD.

Neuropsychological deficits in drug naïve, non-depressed obsessive-compulsive disorder patients

There are several studies that compared neuropsychological performance of OCD patients with healthy controls. However, there are hardly any studies which have used drug-naïve as well as non-depressed OCD subjects in their studies. The present study compared eighteen drug-naïve non-depressed OCD patients with similar number of age, education and sex matched healthy controls on neuropsychological tests. The tests used are block design, object assembly, Visuospatial Working Memory Test, Verbal Working Memory Test, Complex Figure Test, Stroop Test and Wisconsin Card Sorting Test. In addition to usual significance testing, Effect Sizes were calculated. In addition, correlation was done between neuropsychological test variables and clinical variables. The results did not show any significant correlation between any of the clinical variables and neuropsychological test variables. On the other hand, patients showed significant deficits mainly in executive functions and organizational strategy with respect to visuospatial functions. The observed deficits can be attributed to both dorsolateral prefrontal cortex and orbitofrontal cortex involvement.

What checkers actually check: an eye tracking study of inhibitory control and working memory

BACKGROUND

Not only is compulsive checking the most common symptom in Obsessive Compulsive Disorder (OCD) with an estimated prevalence of 50-80% in patients, but approximately ∼15% of the general population reveal subclinical checking tendencies that impact negatively on their performance in daily activities. Therefore, it is critical to understand how checking affects attention and memory in clinical as well as subclinical checkers. Eye fixations are commonly used as indicators for the distribution of attention but research in OCD has revealed mixed results at best.

METHODOLOGY/PRINCIPAL FINDING

Here we report atypical eye movement patterns in subclinical checkers during an ecologically valid working memory (WM) manipulation. Our key manipulation was to present an intermediate probe during the delay period of the memory task, explicitly asking for the location of a letter, which, however, had not been part of the encoding set (i.e., misleading participants). Using eye movement measures we now provide evidence that high checkers' inhibitory impairments for misleading information results in them checking the contents of WM in an atypical manner. Checkers fixate more often and for longer when misleading information is presented than non-checkers. Specifically, checkers spend more time checking stimulus locations as well as locations that had actually been empty during encoding.

CONCLUSIONS/SIGNIFICANCE

We conclude that these atypical eye movement patterns directly reflect internal checking of memory contents and we discuss the implications of our findings for the interpretation of behavioural and neuropsychological data. In addition our results highlight the importance of ecologically valid methodology for revealing the impact of detrimental attention and memory checking on eye movement patterns.

Deficient inhibition of return in subclinical OCD only when attention is directed to the threatening aspects of a stimulus

BACKGROUND

Inhibition of return (IOR) is thought to reflect inhibition of previously attended but irrelevant stimuli. Deficient IOR would increase the likelihood of revisiting previously searched locations or objects, thus leading to unproductive perseverations.

METHOD

Therefore, using a novel IOR task, we investigated whether high scoring checkers attentional biases to threat would result in dysfunctional inhibitory functioning compared to low checkers. In two tasks, we compared 53 subclinical high and 49 low checkers regarding IOR effects for stimuli that were concordant with the concerns of high but not of low checkers (electrical kitchen appliances: e.g., toaster, kettle). The difference between the two tasks was the cueing procedure. In one task, an appliance was switched "ON" and "OFF" as an unpredictive cue, drawing attention to the functionality of the stimulus.

RESULTS

In this task, IOR was specifically attenuated in high checkers. In the other task, however, the cue was more abstract in form of a yellow outline that appeared around one of two appliances. Although the appliance was either "ON" or "OFF," this did not seem to matter and high checkers revealed a typical IOR pattern similar to low checkers.

CONCLUSIONS

We conclude that IOR mechanisms might not be generally deficient in high checkers; rather only when attention is drawn to the threatening aspects of ecologically valid stimuli, then disengagement of attention is deficient in high checkers. We make suggestions on how our task-specific findings may inform cognitive interventions that target attentional control in the treatment of checking/obsessive-compulsive disorder.

Comprehensive evaluation of cortical structure abnormalities in drug-naïve, adult patients with obsessive-compulsive disorder: a surface-based morphometry study

The study objective was to comprehensively evaluate drug-naïve, adult patients with Obsessive Compulsive Disorder (OCD) for cortical structure abnormalities in comparison with healthy controls. In this cross-sectional study of case-control design, Magnetic Resonance Imaging (1-mm) was performed in drug-naïve OCD patients (N = 50) & age- sex-, education- and handedness-matched healthy controls (N = 40). We examined cortical volume, thickness, surface area & local Gyrification Index (LGI) through a completely automated surface-based morphometric analysis using FreeSurfer software. OCD symptoms and insight were assessed using Yale-Brown Obsessive Compulsive Symptom (Y-BOCS) check-list and severity scale. Illness severity was assessed using Clinical Global Impression Severity (CGI-S) Scale. OCD patients had significantly deficient volume, thickness and surface area of right anterior cingulate gyrus (ACG). Right lingual gyrus surface area was found to be significantly decreased in patients. Y-BOCS obsession score had significant negative correlation with left frontal pole volume. Y-BOCS compulsion score had significant negative correlations with right ACG volume and surface area and right lateral orbitofrontal cortex LGI. CGI-Severity score had significant negative correlations with right lingual gyrus volume, thickness and surface area as well as right lateral orbitofrontal area. Y-BOCS insight score showed a significant negative correlation with LGI of left medial OFC and left rostral ACG. Identification of novel deficits involving occipital brain regions and first-time observations of relevant correlations between various illness characteristics and cortical measures in OCD patients supports a network involving anterior cingulate, orbitofrontal and occipital brain regions in the pathogenesis of OCD.

Impaired executive functioning in subclinical compulsive checking with ecologically valid stimuli in a working memory task

We previously showed that working memory (WM) performance of subclinical checkers can be affected if they are presented with irrelevant but misleading information during the retention period (Harkin and Kessler, 2009, 2011). The present study differed from our previous research in the three crucial aspects. Firstly, we employed ecologically valid stimuli in form of electrical kitchen appliances on a kitchen countertop in order to address previous criticism of our research with letters in locations as these may not have tapped into the primary concerns of checkers. Secondly, we tested whether these ecological stimuli would allow us to employ a simpler (un-blocked) design while obtaining similarly robust results. Thirdly, in Experiment 2 we improved the measure of confidence as a metacognitive variable by using a quantitative scale (0–100), which indeed revealed more robust effects that were quantitatively related to accuracy of performance. The task in the present study was to memorize four appliances, including their states (on/off), and their locations on the kitchen countertop. Memory accuracy was tested for the states of appliances in Experiment 1, and for their locations in Experiment 2. Intermediate probes were identical in both experiments and were administered during retention on 66.7% of the trials with 50% resolvable and 50% irresolvable/misleading probes. Experiment 1 revealed the efficacy of the employed stimuli by revealing a general impairment of high- compared to low checkers, which confirmed the ecological validity of our stimuli. In Experiment 2 we observed the expected, more differentiated pattern: High checkers were not generally affected in their WM performance (i.e., no general capacity issue); instead they showed a particular impairment in the misleading distractor-probe condition. Also, high checkers’ confidence ratings were indicative of a general impairment in metacognitive functioning. We discuss how specific executive dysfunction and general metacognitive impairment may affect memory traces in the short- and in the long-term.

Beneficial effects of electrostimulation contingencies on sustained attention and electrocortical activity

INTRODUCTION

Chinese acupuncture therapy has been practiced for more than 3000 years. According to neuroimaging studies, electroacupuncture has been demonstrated to be effective via control of the frequency parameter of stimulation, based on the theory of frequency modulation of brain function.

AIMS

To investigate the following: (1) possible sustained effects of acustimulation in improving perceptual sensitivity in attention by comparing before, during, and 5 min following stimulation; (2) relations between commission errors and the motor inhibition event-related potential (ERP) component measured with independent component analysis (ICA); (3) whether habituation would be demonstrated in the sham control group and would be militated by acustimulation in the experimental groups.

RESULTS

Twenty-seven subjects were divided into three groups (n = 9). d-Prime (d') derived from signal detection theory was used as an index of perceptual sensitivity in the visual continuous performance attention test. Increased d' was found during both alternating frequency (AE) and low frequency (LE) stimulation, but with no change in the sham control group (SE). However, only following AE was there a sustained poststimulation effect. Spatial filtration-based independent components (ICs) in the AE group revealed significantly decreased amplitudes of the motor inhibition ICs both during and poststimulation. There was a significant habituation effect from task repetition in the sham group with decreased amplitudes of ICs as follows: the visual comparison component difference between go (correct response) and nogo cues (correct withheld response), the P400 action monitoring and the working memory component in the nogo condition, and the passive auditory component on control trials.

CONCLUSION

The results showed associations between acustimulation and improved perceptual sensitivity with sustained improvements following AE, but not LE stimulation. Improvements in commission errors in the AE group were related to the motor inhibition IC. The activational effects of acustimulation apparently attenuated the across-task habituation that characterized the control group.

Measuring obsessive-compulsive symptoms: Padua Inventory-Revised vs. Yale-Brown Obsessive Compulsive Scale

Although the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and the Padua Inventory-Revised (PI-R) are the most widely used instruments for assessing presence and severity of symptoms in obsessive-compulsive disorder (OCD), the correlation between the two instruments is surprisingly low. The aim of the present investigation was to test two possible explanations for the discrepancy between these instruments by comparing both scales in 120 OCD patients. The tested hypotheses included: (1) differences in the way the measures are administered, i.e. observer-rated vs. self-rated; and (2) differences in the way severity is calculated, i.e. the PI-R measures severity by aggregating symptoms, while the Y-BOCS measures severity unrelated to the number of symptoms. Results indicated that neither hypothesis satisfactorily explains the differences between the measures. The investigation concludes that the Y-BOCS and PI-R measure relatively unrelated features of OCD, and the combined use of multiple measures is recommended to assess the complexity of OCD phenomena.

Impairment of source memory in patients with obsessive-compulsive disorder: equivalent current dipole analysis

We examined memory performance and cortical source localization of old/new effects in a source memory task in obsessive-compulsive disorder (OCD) patients by employing an equivalent current dipole (ECD) model using EEG and a realistic head model. Event-related potentials (ERPs) were recorded while 14 OCD patients and 14 age-, sex-, handedness-, and educational level-matched healthy control subjects performed recognition tasks for spoken words (items) or for the voice of the speaker of spoken words (sources). In the item memory task, both groups showed ERP old/new effects at 300-700 ms. In the source memory task, the controls showed ERP old/new effects at 400-700 ms, whereas the OCD patients did not. Compared with the controls, the OCD patients showed significantly lower source accuracy and prolonged reaction times to the old words with accurate voice judgments. There were no differences between the OCD and control groups with regard to the locations of the ERP generators elicited by source correct and correct rejection conditions. The OCD patients showed significantly altered hemispheric asymmetry of ECD power in the frontal lobe during source memory retrieval, compared with the controls. These results indicate that OCD patients have preserved item memory about content, but impaired source memory about context.

Temperament and executive dysfunctions in schizophrenia

Recent studies suggest that both executive dysfunction and personality traits combine with symptoms to affect the social outcome of persons with schizophrenia. This study was designed to investigate how personality traits influence executive function in schizophrenia. Forty-four patients with schizophrenia and twenty-two healthy subjects were assessed for personality using the temperament and character inventory. Different aspects of executive function were assessed using the Auditory Digit Span (forward and backward) and the Wickens' test for proactive interference and release. The results showed that the influences of the various temperament dimensions on specific aspects of executive functions differ between patients and healthy subjects. On some dimensions, schizophrenia appears to reduce the cognitive differences related to temperament. On other dimensions, schizophrenia tends to reverse the cognitive differences related to temperament observed in healthy people. These results suggest that the temperamental profile of schizophrenia patients may well be of important prognostic value in the planning of cognitive enhancement therapy.

Equivalent Current Dipole of Word Repetition Effects in Patients with Obsessive-Compulsive Disorder

We investigated cortical source localization of word repetition effects in patients with obsessive-compulsive disorder (OCD) by employing the equivalent current dipole (ECD) model with high-density 128 channels EEG and individual MRI as a realistic head model. Twelve OCD patients and 13 healthy control subjects performed a word/nonword discrimination task, in which the words and nonwords were visually presented, and some of the words appeared twice with a lag of one or five items. During the 200-500 ms post-stimulus period, the control group showed more positivity in the ERPs elicited by old words than in those elicited by new words, whereas the OCD patients did not. Furthermore, the OCD patients showed prolonged response times to the old words, as compared to the controls. We calculated the location and the power of the ECD sources at approximately 400 ms post-stimulus with the peak mean global field potentials. In both groups, the sources of word repetition effects were determined to be located in the inferior frontal gyrus. The right ECD powers of the ERP generators elicited by the new words were significantly higher in the OCD patients than in the control subjects. The OCD patients also exhibited significant alterations in the hemispheric asymmetry of ECD power during the processing of new words. These results suggest that OCD patients suffer from the encoding deficits in word processing, particularly in the left hemisphere.

Neuropsychological performance in obsessive-compulsive disorder: a critical review

There is growing evidence for neuropsychological dysfunction in obsessive-compulsive disorder (OCD) related to an underlying frontal lobe and/or basal ganglia dysfunction. The following paper is a systematical review of the existing literature on cognitive impairment in OCD patients. Fifty studies were surveyed with regard to methodological aspects and cognitive impairments found in OCD patients. In addition, the impact of confounding variables such as psychotropic medication, co-morbidity or severity of symptoms on neuropsychological functioning as well as effects of treatment are discussed. OCD is often related to memory dysfunction that seems to be associated with impaired organization of information at the stage of encoding. Several other executive functions are also commonly disturbed, though results are inconsistent. The results of our study suggest that some cognitive deficits seem to be common in OCD, but future studies should focus more on possible confounding variables such as co-morbidity or psychotropic medication.

The decade 1989-1998 in Spanish psychology: an analysis of research in psychobiology

In this paper, we present an analysis of the research published during the 1989-1998 decade by tenured Spanish faculty members from the area of psychobiology. Database search and direct correspondence with the 110 faculty members rendered a list of 904 psychobiological papers. Classification and analysis of these papers led to the definition of at least 70 different research trends. Topics are grouped into several specific research areas: Learning and Memory; Development and Neural Plasticity; Emotion and Stress; Ethology; Neuropsychology; Sensory Processing; and Psychopharmacology. The international dissemination of this research, published in journals of high impact index, and the increasing number of papers are two noteworthy features.

Sustained attention in patients with obsessive-compulsive disorder: a controlled study

Studies on attentional processes in obsessive-compulsive disorder (OCD) have been inconsistent. The present study focused on the question of sustained attention in OCD, using the 'Degraded Stimulus Continuous Performance Test' (DS-CPT) sensitivity index over time. This study included 20 OCD patients and 25 control subjects, comparable in sex, age and educational level. All subjects had a neuropsychiatric structured diagnostic interview, as well as a psychometric battery. The DS-CPT evaluated sustained attention. The sensitivity decrement during DS-CPT was significant in both controls and OCD subjects. Contrary to our expectations, OCD patients did not show a greater decrease in sensitivity over time, compared to controls: thus, OCD patients presented a no more important attention decrease than controls. Controls and OCD subjects became more conservative in their response criteria throughout the DS-CPT test. Comparing OCD with and without pharmacological treatment did not reveal any difference in CPT outcome. Moreover, we observed, in OCD, a positive significant correlation between the Y-BOCS compulsion score and the CPT sensitivity index. A significant negative correlation of the Y-BOCS compulsive score with the CPT false alarm score was also found. In conclusion, OCD patients did not present any disturbance in sustained attention during a task requiring an increased processing load.

Neuropsychological functioning in a subclinical obsessive-compulsive sample

BACKGROUND

Previous neuropsychological research has suggested that the study of psychometrically defined subclinical samples might be a valid approach to understand the underlying pathophysiology of obsessive-compulsive disorder (OCD). This approach has the potential benefit of overcoming some of the methodological problems linked to the use of clinical samples.

METHODS

A group of subclinical obsessive-compulsive (OC) subjects (n = 35), selected on the basis of their scores on the Padua Inventory, and a control group were assessed on executive functioning tasks and other neuropsychological tests which have been demonstrated to be impaired in clinical OCD patients and/or in those with several basal ganglia disorders.

RESULTS

Subclinical OC subjects needed significantly more moves than controls to reach the solution criteria on the Tower of Hanoi puzzle, and performance on this test was positively correlated with total score and the Checking factor of the Padua Inventory. There were no between-group differences on the other frontal lobe tests.

CONCLUSIONS

The results suggest that deficits in manipulating spatial information might be basic in OCD, and are congruent with the involvement of the frontostriatal circuits in the disorder.