Marc E. Lavoie

Modulation of cognitive processing by emotional valence studied through event-related potentials in humans.

This experiment investigated whether the emotional content of a stimulus could modulate its cognitive processing. Particularly, we focused on the influence of the valence dimension on the cognitive processing triggered by a non emotional oddball task. To this end, event-related potentials (ERPs) were recorded from 25 sites during a visual oddball paradigm. Three sets of pictures (unpleasant, neutral and pleasant) with low arousal values served as rare target items. Subjects were simply asked to realize a standard/target categorization task, irrespective of the picture valence. A temporal principal component analysis allowed us to identify several evoked components (i.e. P1, P2, N2, P3a and P3b). Emotional effects observed on P1, P2 and P3b showed that the valence content of the stimulus modulates the cognitive processes at several points in the information processing stream.

Concussions in athletes produce brain dysfunction as revealed by event-related potentials

We have used event-related potentials (ERP) to assess cerebral activity following mild traumatic brain injuries in 20 college athletes practising contact sports. Concussion victims showed a striking decrease in P300 amplitude, an effect presumed to reflect alterations in attentional-cognitive processes. Moreover, the degree of impairment was strongly related to the severity of post-concussion symptoms. Our data suggest that concussions cause objectively measurable changes in the electro-physiological markers of brain activity and hence in the functions of the structures from which they originate. ERPs may thus constitute a reliable method to accurately monitor the clinical course and recovery of head injuries in athletes.

Visual P300 Effects Beyond Symptoms in Concussed College Athletes

In order to assess whether cerebral anomalies may be observed in the absence of clinical symptoms, the current study compared the effects of concussions on attentional capacities (reaction times, accuracy) and Event-Related Potentials (ERPs) in concussed athletes with (n = 10) or without (n = 10) symptoms as well as in athletes who never had a concussion (n = 10). The P300 response was recorded from 28 electrodes during a modified visual oddball paradigm. Participants were instructed to press a key upon the appearance of the frequent stimuli as well as when a rare nontarget stimulus followed the frequent one. The other key was to be pressed when the subsequent rare stimuli (rare target) appeared until a frequent one reappeared. The symptomatic athletes displayed longer reaction times than the other two groups of athletes. The P300 amplitude to the rare target stimuli was significantly more attenuated in the symptomatic athletes than in the other two groups. Moreover, the P300 amplitude varied inversely with the severity of postconcussion symptoms but was not influenced by time elapsed since injury. Although the clinical significance of the P300 differences shown by the symptomatic athletes is still uncertain, the results do indicate that symptom severity may be a crucial indicator of functional impairments following mild traumatic brain injury.

Cognitive behavioral management of Tourette's syndrome and chronic tic disorder in medicated and unmedicated samples.

OBJECTIVE Cognitive behavior therapy (CBT) and medication can be administered in combination in treating tic disorders but there are no studies evaluating the effectiveness of CBT with and without medication. The current study compares the efficacy of CBT in combination with medication and without medication. METHOD CBT was administered in a consecutively referred sample of 76 people diagnosed either with Gilles de la Tourette Syndrome or chronic tic disorder. The sample was divided into a medicated and a non-medicated group. Twenty three were stabilized on medication and 53 were not receiving medication. Measures administered pre- and post-CBT in both groups included: main outcome measure of Tourette Syndrome Global Scale and measures of mood. RESULTS Repeated measures analysis of variance on the initial sample revealed no difference between medicated and non-medicated groups in outcome. A further analysis comparing the 23 receiving medication with 23 not receiving medication matched on baseline clinical variables also yielded no significant group differences, either in treatment outcome on main tic outcome measures or on other clinically relevant questionnaires. DISCUSSION CBT for tic disorders is an effective treatment administered either in combination with medication or alone.

Neural correlates of emotional recognition memory in schizophrenia: effects of valence and arousal.

Schizophrenia patients are often impaired in their memory for emotional events compared with healthy subjects. Investigations of the neural correlates of emotional memory in schizophrenia patients are scarce in the literature. The present study aimed to compare cerebral activations in schizophrenia patients and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. In a study with functional magnetic resonance imaging, 37 schizophrenia patients were compared with 37 healthy participants while performing a yes/no recognition paradigm with positive, negative (differing in arousal intensity) and neutral images. Schizophrenia patients performed worse than healthy controls in all experimental conditions. They showed less cerebral activation in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activation compared with controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal lobe and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. Our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in schizophrenia patients. The arousal data revealed that schizophrenia patients closely resemble the control group at both the behavioral and neurofunctional level.

Memory and executive functions in adults with Gilles de la Tourette syndrome and chronic tic disorder

Introduction. The main aim of the current study was to assess whether adults with either Tourette syndrome (TS) or chronic tic disorder (CTD) show a similar neuropsychological profile. Neuropsychological investigations of tic disorders have been mostly focused on children, mainly because symptoms peak during that period. Little has been carried out on adults, even if a significant proportion of the tic population experience moderate or marked levels of tic frequency throughout adulthood. Still, it is not clear whether neuropsychological performances are affected to the same degree in adults with TS and CTD. Method. Patients diagnosed with TS were compared with a CTD group and a control group free of psychiatric or neurological diagnosis, comparable in terms of age, gender, and intelligence. All participants completed two tests of memory (Rey-Osterreich Complex Figure, California Verbal Learning Test), one test of motor dexterity (Purdue pegboard), and four tasks of executive function (Stroop, Color Trail Test, Tower of London, Wisconsin Card Sorting Test). Results. TS and CTD patients showed nonverbal memory impairments while verbal memory and executive functioning remained intact. Results also indicated that nonverbal memory performances decrease as a function of tic severity. Conclusion. Both TS and CTD patients present a specific nonverbal deficit whilst the executive and motor functions are relatively intact. The two tic disorder subgroups might be part of a spectrum implicating mainly nonverbal memory.

Electrophysiological manifestations of stimulus evaluation, response inhibition and motor processing in Tourette syndrome patients

Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder with childhood onset presenting with multiple fluctuating motor tics and one or more phonic tics. A significant proportion of people suffering from GTS are still symptomatic in adulthood and present other emotional and cognitive difficulties, along with motor problems that often accompany these comorbid conditions. The nature of these difficulties is still poorly understood and multiple comorbidities are often inadequately controlled. The current study investigates both stimulus evaluation and motor processing in GTS while controlling for comorbidity. Fifteen adults with GTS and 20 control participants were matched on gender, laterality and intelligence. The P300 component, the no-go anteriorization (NGA) as well as the stimulus and response-locked lateralized-readiness potentials (S-LRP, R-LRP) were elicited during a stimulus-response compatibility (SRC) paradigm. The standard version of the Stroop Color-Word Test (SCWT) was also administered. Reaction times showed that participants with GTS processed both the SRC and the SCWT more rapidly than the control group, while producing a delayed P300 peak latency. The GTS group also showed faster S-LRP onset in response to the incompatible and faster processing of interference in the SCWT. There was also a tendency toward a greater frontal shift of the NGA in the GTS group. The P300 latency showed that with GTS patients, stimulus evaluation occurs later whereas the overlapping pre-motor response selection processes occur faster. Our findings are congruent with a probable cortical motor over-activation hypothesis of GTS involving faster motor program selection in processing conflicting SR configuration.

Evaluation of a cognitive psychophysiological model for management of tic disorders: an open trial

BACKGROUND Tic disorders, in particular chronic tic disorder and Tourette syndrome, affect about 1% of the population. The current treatment of choice is pharmacological or behavioural, addressing tics or the premonitory urges preceding tic onset. AIMS The current study reports an open trial evaluating the effectiveness of a cognitive psychophysiological treatment addressing Tourette-specific sensorimotor activation processes rather than the tic. METHOD Forty-nine people with Tourette syndrome and 36 people with chronic tics completed 10 weeks of individual cognitive psychophysiological therapy. Outcome measures included two tic severity scales and psychosocial measures. RESULTS Post-treatment both groups had significantly improved on the tic scales with strong effect sizes across tic locations and complex and simple tics, maintained at 6-month follow-up with further change in perfectionism and self-esteem. CONCLUSIONS The cognitive psychophysiological approach targeting underlying sensorimotor processes rather than tics in Tourettes and chronic tic disorder reduced symptoms with a large effect size.

Meta-Cognitions in Tourette Syndrome, Tic Disorders, and Body-Focused Repetitive Disorder

Objective: To explore if self-reported presence of thinking about tics or body-focused repetitive behaviours (BFRBs; gests) are direct triggers of tic or gest onset in 3 groups: Tourette syndrome (TS; n =18), persistent chronic tic disorders (TDs; n = 42), and a comparison group with BFRB (n = 36). Method: The 3 groups completed a thinking about tics inventory, listing 22 items derived from clinician consensus that asked whether thoughts always, sometimes, or never exclusively triggered tic onset. Other questionnaires measured mood, perfectionism, impulsivity, premonitory urge, and self-rated tension. Sixty-three participants completed the inventory twice, and the inventory was completed pre- and post-behavioural intervention by a further 54. Results: The ranking of the thoughts reported as likely to trigger tics or gests was positively correlated across TD and BFRB groups. Exploratory principal components analysis of a reduced 12-item set (the thinking about tics inventory) in TS and TD groups revealed that such thoughts could be grouped into 3 separate subscales: thoughts about the interference of tics or gests, thoughts anticipating tics or gests, and thoughts about whether the person has permission to perform the tic or the gest. The 3 sets of subscales showed good and acceptable internal consistency and overall score showed good test–retest reliability, suggesting thoughts about tics or gests are robust and measurable. The subscales correlated with impulsivity, tic or behaviour severity, and ratings of frequency decreased post-behavioural treatment. Conclusions: Thinking about tics or gests is reported as triggering tics or gests in both TD and BFRB, and meta-cognition seems independent of premonitory sensations and relates to distinct clinical characteristics in each clinical group.

Sex differences in memory processing in schizophrenia: An event-related potential (ERP) study

Recently, research has begun to examine sex differences in cognitive functions in schizophrenia and whether such sex differences reflect normal, exaggerated, or reversed sexual dimorphism. This study examined this question by using event-related potentials (ERPs). ERPs were recorded in a recognition memory task in 18 patients and 18 matched control subjects. On an early frontal component, the results show an interaction between sex and pathological condition that results in an apparent reversed sexual dimorphism. On mid-latency components, patients show no sex difference on a frontal component, but a difference on the posterior component, whereas healthy subjects show a reverse pattern. Finally, late components show sex difference in the same direction as healthy subjects. These results indicate that the influence of sex on the cognitive impairment in schizophrenia is not homogenous across the information-processing cascade.