Biomedical subjects

Paraskevi Mavrogiorgou

Publications and source records attributed to Paraskevi Mavrogiorgou.

6 recordsLinked to original sources

PubMed2007

Facial expressions and personality: a kinematical investigation during an emotion induction experiment.

BACKGROUND/AIMS: In order to elucidate the relationship between personality traits and expression of positive emotions in healthy volunteers, standardized personality inventories and kinematical analysis of facial expressions can be helpful and were applied in the present study. METHODS: Markers fixed at distinct points of the face emitting ultrasonic signals at high frequency gave a direct measure of facial movements with high spatial-temporal resolution. Forty-six healthy participants (mean age: 40.7 years; 20 males, 26 females) watching a witty movie ("Mr. Bean") were investigated. RESULTS: Speed of "laughing" was associated with higher scores on Zuckerman's Sensation Seeking Scale and NEO-FFI (Openness to Experience). CONCLUSION: Kinematical analysis of facial expressions seems to reflect sensation seeking and related personality styles. Higher speed of facial movements in sensation seekers suggests lowered serotonergic function.

Adult↗

PubMed2006

Symptom-specific EEG power correlations in patients with obsessive-compulsive disorder.

Neurophysiological studies in patients with obsessive-compulsive disorder (OCD) consistently revealed frontal alterations of cortical activity but otherwise showed inhomogeneous results, conceivably due to variable subgroups with diverse pathomechanisms involved. The aim of this study was to investigate quantitative electroencephalography (EEG) in patients with OCD as compared to healthy controls and to correlate neurophysiological data with clinical variables. EEGs were digitally recorded from 18 unmedicated patients (8 male, mean age 32.4+/-11.8 years, Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) 15.3+/-7.9) and 18 matched healthy controls, and analysed quantitatively. The mean frequency of EEG background activity and absolute power in delta, theta, alpha and beta frequency bands were calculated. Mean frequency of background activity was significantly lower in patients as compared to controls (-1.44/s, p<0.01), predominantly for the frontal electrode positions. Power spectra revealed increased delta- and decreased alpha-/beta-power in the group of patients (p<0.05, patients vs. controls). Correlation analyses showed significant positive correlations of EEG-power with the Y-BOCS sub-scores "obsessions", and negative correlations with the sub-scores "compulsions" (Spearman's correlations, r(s)=+0.48 to +0.70, and -0.47 to -0.6, respectively, p<0.05). The data provide evidence of a dysfunction of frontal cortical activity in patients with OCD. The opposite correlations of neurophysiological data and clinical features, i.e. obsessions and compulsions, are suggestive of pathophysiological differences based on the presence of the respective cardinal symptoms of OCD.

Adolescent↗

PubMed2006

A Ser9Gly polymorphism in the dopamine D3 receptor gene (DRD3) and event-related P300 potentials.

An important reason for the interest in P300 event-related potentials are findings in patients with psychiatric disorders like schizophrenia or alcoholism in which attenuations of the P300 amplitude are common findings. The P300 wave has been suggested to be a promising endophenotype for genetic research since attenuations of the amplitude and latency can be observed not only in patients but also in relatives. In parallel, the search for genes involved in the pathogenesis of psychiatric disorders has revealed for both, schizophrenia and alcoholism an association with a DRD3 Ser9Gly polymorphism in a number of studies. In the present study, we have investigated 124 unrelated healthy subjects of German descent and have found diminished parietal and increased frontal P300 amplitudes in Gly9 homozygotes in comparison to Ser9 carriers. This finding suggests a possible role of the DRD3 receptor gene in the interindividual variation of P300 amplitudes. Further studies should address the direct role of the DRD3 Ser9Gly polymorphism in attenuated P300 amplitudes in psychiatric disorders like schizophrenia or alcoholism.

Acoustic Stimulation↗

PubMed2005

Can a subgroup of OCD patients with motor abnormalities and poor therapeutic response be identified?

RATIONALE: In a subgroup of patients with obsessive-compulsive disorder (OCD), motor soft signs, tics and other movement disorders can be observed, indicating a special pathogenetic involvement of basal ganglia. OBJECTIVES: The main objective of this study was to verify the hypothesis that such motor dysfunction characterises a subgroup of OCD patients with poor treatment response. For assessing even subtle motor dysfunction, a new method for kinematical analysis of hand movements has been applied. METHODS: We examined the performance of 45 in-patients who met the DSM-IV criteria for OCD before and under therapy (sertraline and behaviour therapy) using a digitising tablet and kinematical analysis of simple handwriting and drawing movements. All subjects wrote a sentence, their signature and letter sequences. Moreover, they drew circles under different conditions. Three kinematical parameters (stroke duration, variation coefficient of peak velocity, stroke length) were calculated to quantify hand-motor performance. RESULTS: Prior to therapy, non-responders wrote with significantly smaller amplitudes than responders. Additionally, non-responders drew significantly larger circles with the non-dominant hand at baseline, as compared to responders. Disturbances of handwriting were more frequent in non-responders than in responders. CONCLUSIONS: Kinematical analysis of handwriting movements seems to be interesting for the prediction of poor response to treatments in OCD patients.

Adult↗

PubMed2003

Effects of sertraline on kinematic aspects of hand movements in patients with obsessive-compulsive disorder.

RATIONALE: Movement disorders such as disturbances of fine motor co-ordination are a frequent phenomenon in patients with obsessive-compulsive disorder (OCD). OBJECTIVES: Our aim was to investigate changes of hand-motor dysfunction in OCD patients under the influence of 10-week treatment with sertraline and behaviour therapy. METHODS: We examined the performance of 40 patients satisfying DSM-IV criteria for OCD before and under this therapy using a digitising tablet and kinematic analysis of handwriting and drawing movements. Forty healthy controls were also tested (test-retest interval: 10 weeks). RESULTS: The speed of drawing was significantly lower in OCD patients than in controls (mean+/-standard deviation=197.03+/-113.26 mm/s for patients and 182.48+/-189.61 mm/s for controls; P=0.01). After 10 weeks of therapy, this parameter normalised in patients (from 197.03+/-113.26 mm/s to 163.66+/-101.92 mm/s; P=0.001). CONCLUSIONS: Hand-motor dysfunction (especially bradykinesia) improves with a serotonin-enhancing therapy in OCD patients.

Adult↗

PubMedDate not supplied

P300 subcomponents in obsessive-compulsive disorder.

Hyperactivity in the frontal cortex, leading to acceleration of attentional and cognitive processes, is discussed as pathogenetic factor in obsessive-compulsive disorder (OCD), as supported by findings of neuroimaging studies. This dysfunction in patients with OCD could be reflected by the auditory event-related P300 component, since one subcomponent of the P300, the so-called P3a, is mainly generated in frontal regions. The P300 of 21 patients with OCD free of medication and 21 age- and sex-matched healthy controls was studied, and dipole source analysis was used, allowing the separation of the subcomponents P3a and P3b with high reliability. No difference concerning the P3a between OCD and healthy subjects was found. OCD patients, however, showed a larger P3b amplitude and a shorter P3b latency (only right hemisphere) as well as a shorter reaction time to target tones as the healthy controls. Since the P3b, generated mainly in the temporo-parietal junction, is related to attentional and higher cognitive functions, whereas the P3a is more related to unspecific orienting reactions, the P3b abnormalities found in these patients could be an electrophysiological correlate of overfocussed attention and faster cognitive processes in OCD, possibly due to higher arousal and noradrenergic function. Regarding the findings with small P300 amplitudes and long latencies in most of the other psychiatric patients, it is remarkable that OCD is one of the few psychiatric diseases being characterized by larger P3b amplitudes and shorter latencies.

Adult↗