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Biomedical subjects

Kurt Audenaert

Publications and source records attributed to Kurt Audenaert.

At least 19 recordsLinked to original sources
PubMed2006

Does regional brain perfusion correlate with eating disorder symptoms in anorexia and bulimia nervosa patients?

OBJECTIVE: Using single photon emission computed tomography (SPECT), we sought brain perfusion correlates of eating disorder symptoms in anorexia and bulimia nervosa patients. METHOD: We investigated 67 female eating disordered (ED) patients. Eating disorder symptoms were measured by the Eating Disorders Inventory (EDI). Determination of brain areas in which regional perfusion co-varied with drive for thinness, bulimia, body dissatisfaction, ineffectiveness, perfectionism, interpersonal distrust, interoceptive awareness and maturity fears was done by open explorative correlation analysis using Statistical Parametrical Mapping (SPM). RESULTS: A significant positive correlation between scores on body dissatisfaction and ineffectiveness, and brain perfusion in the prefrontal and parietal cortex was demonstrated. There were no correlations between other eating disorder symptoms and brain perfusion. CONCLUSION: Based on the finding of an association between regional brain flow and body dissatisfaction and ineffectiveness, we argue that neurobiological findings in ED patients may not only reflect emotional and behavioural factors but cognitive-evaluative features as well.

Adult↗
PubMed2006

Serotonin transporter and dopamine transporter imaging in the canine brain.

The serotonergic and dopaminergic systems are involved in a wide range of emotional and behavioral aspects of animals and humans and are involved in many neuropsychiatric disorders. Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are designed to block the 5-HT transporter (SERT), thereby increasing the available 5-HT in the brain. Functional imaging with specific SERT and dopamine transporter (DAT) ligands contributes to the study of the SSRI-transporter interaction. First, we evaluated the feasibility of a canine model in the study of the SERT and DAT with the radioligands [123I]-beta-CIT and [123I]-FP-CIT as well as single-photon emission computed tomography imaging. Second, we studied the effect of SSRIs (sertraline, citalopram and escitalopram) on the SERT and DAT in two dogs. The position of the canine model in the study of the SERT and DAT is discussed and compared with other animal models.

Animals↗
PubMed2005

Suicide among adolescents. A psychological autopsy study of psychiatric, psychosocial and personality-related risk factors.

BACKGROUND: The suicide rate among young males in Belgium has doubled over the last decade. As more knowledge about risk factors is required to develop national prevention strategies, we investigated adolescent suicides using the psychological autopsy method. METHODS: A total of 32 informants were interviewed regarding 19 suicide cases (aged 15-19). A semi-structured interview schedule, constructed by Houston et al. (J Affect Disord 63:159-170, 2001), was used. RESULTS: All adolescents were suffering from one or more mental disorder(s) at the time of their death, and almost half of them were diagnosed with personality disorders. Adjustment disorders were diagnosed in one fifth of the sample, which appears to be relevant in view of the multiple life events and other psychosocial problems which adolescents were facing shortly before death. This suggests that difficulties in coping with stressful psychosocial problems are important in the course of the suicidal process. Only a small minority was receiving treatment for their disorders. CONCLUSIONS: Mental disorders, commonly untreated and combined with personality disorders and psychosocial problems, are frequently found in young suicide victims. This study suggests that education in the diagnosis and treatment of depression, adjustment disorders and suicide is important in the prevention of suicide.

Adolescent↗
PubMed2005

Effect of repetitive transcranial magnetic stimulation on saccades in depression: a pilot study.

Therapeutic repetitive transcranial magnetic stimulation (rTMS) in depression is applied over the prefrontal cortex. This brain region is known to play an important role in the control of saccades. We wanted to investigate whether the fast rTMS procedure affected saccadic activity in depression. Reflexive saccades (RS) and voluntary saccades were studied in 11 patients before and after therapeutic rTMS for depression. Two types of voluntary saccade tasks were used: a voluntary prosaccade (VpS) task and an antisaccade (AS) task. Eye movements were registered by infrared oculography. Latency and directional error rate were analyzed. rTMS was applied over the left dorsolateral prefrontal cortex (DLPFC). RS and VpS parameters were unchanged after 10 sessions of rTMS. However, the latency of antisaccades (AS) was significantly shorter after rTMS than before rTMS. It can be concluded that rTMS over the left DLPFC cortex in depression seems to have no important effect on reflexive saccades, while antisaccade activity is clearly favored by shortening of latency. As voluntary prosaccades were not significantly influenced, our findings may indicate that not merely the voluntary triggering of saccades but the inhibition of unwanted reflexive saccades is influenced by fast rTMS delivered over the DLPFC. These results suggest the intriguing possibility that rTMS might differentially affect specific aspects of saccade behavior.

Adult↗
PubMed2005

Differences of cortical 5-HT2A receptor binding index with SPECT in subtypes of anorexia nervosa: relationship with personality traits?

OBJECTIVE: Using single photon emission computed tomography and the 5-HT2A receptor antagonist, 123I-5-I-R91150, we explored differences in 5-HT2A binding index in anorexia nervosa patients with and without bulimic features. We also searched for associations between temperament dimensions and cortical 5-HT2) binding. METHOD: About 9 restrictive and 7 bulimic anorexia nervosa patients were examined and cortical 123I-5-I-R91150 binding index values were compared between the two subgroups. Open explorative correlation analysis was used to examine any relationships between binding index values and temperament scores, as assessed with the Temperament and Character Inventory. RESULTS: 5-HT2A binding index was significantly reduced in the parietal cortex in bulimic anorexia nervosa patients in comparison with restrictive anorectics. Further, a positive correlation was documented between reward dependence and parietal 5-HT2A binding index across patients in the two subgroups. DISCUSSION: Restrictive anorexia nervosa patients differ from binging/purging anorexia nervosa patients on the basis of a reduced parietal 5-HT2A binding index in the latter. We speculate that the finding of a positive correlation between parietal 5-HT2A binding and reward dependence might reflect an association between these two variables, at least in anorexia nervosa patients.

Adolescent↗
PubMed2005

Blunted prefrontal perfusion in depressed patients performing the Tower of London task.

Impairment of cognition is common in depression, and many tasks on which depressed patients are impaired are sensitive to frontal lobe dysfunction. Performance on the Tower of London (TOL) task, which includes setting up and maintaining multiple subgoals at the same time, has been shown to depend on intact prefrontal cortices. Single photon emission computed tomography (SPECT) with 99mTc-ethyl cysteinate dimer was used to compare cognitive activation in nine depressed patients and nine normal controls during performance of the TOL task. Planning times and accuracy were measured as performance parameters, and functional imaging data were analysed with statistical parametric mapping (SPM99) to determine significant voxel-wise differences in activation between the two groups. During activation, depressed patients were as accurate as controls but differed in that they spent more thinking time. These findings agree with the results of neuropsychological studies. Compared with the normal controls, depressed patients were characterized by a blunted perfusion response in the right middle frontal cortex [Brodmann area (BA) 6] and the left superior frontal gyrus (BA 9), and by increased perfusion in the right superior temporal gyrus (BA 21) and the insular cortex (BA 13). This study shows that a SPECT activation procedure using the TOL task under classical test conditions is feasible in depressed patients.

Adult↗
PubMed2005

Brain perfusion SPECT in impulsivity-related personality disorders.

BACKGROUND: Impulsive behaviours in patients with cluster B personality disorders are associated with low glucose metabolism and regional cerebral blood flow in the frontal cortex and subcortical structures. The aim of this study is to confirm the presence of a particular pattern of brain perfusion in a sample of borderline (BPD) and anti-social personality disorder (ASPD) patients using brain perfusion single photon emission computed tomography (SPECT). METHODS: A brain perfusion SPECT study was performed in 37 patients with BPD or ASPD (and no Axis I diagnosis) and 34 healthy control participants. Data were acquired on a triple head Toshiba gamma camera. Scatter and attenuation correction was done. Reconstructed SPECT images were analyzed by Statistical Parametrical Mapping (SPM99). RESULTS: There were no significant differences in age and gender distributions between the patients and the healthy controls. With regard to the functional imaging results, patients were characterized by a reduced regional cerebral blood flow (rCBF) in right temporal and prefrontal brain areas, including the right lateral temporal cortex (BA 21), the right frontopolar cortex (BA 10) and the right ventrolateral prefontal cortex (BA 47). CONCLUSIONS: Patients with BPD and ASPD who showed impulsive behaviour have diminished rCBF in areas of the right prefrontal and temporal cortex.

Adult↗
PubMed2005

Adjustment disorder and the course of the suicidal process in adolescents.

BACKGROUND: Adjustment disorders are often associated with suicidal behaviour but there is little information regarding the nature of the relationship and the effect of adjustment disorders on the suicidal process. The authors' goal was to investigate the association of adjustment disorders (with depressed mood) and suicide in adolescents by means of a psychological autopsy study. METHOD: Relatives and other informants of 19 suicide victims were interviewed by means of a semi-structured interview schedule. Differences in duration of the suicidal process between suicide victims diagnosed with adjustment disorder and suicide cases diagnosed with other psychiatric disorders were examined. RESULTS: The suicidal process was significantly shorter in suicide victims diagnosed with adjustment disorder compared with suicide cases diagnosed with other disorders. No indications of a history of emotional or behavioural problems during early adolescence were found in suicide cases diagnosed with adjustment disorder. LIMITATIONS: The study sample consists of a small sample size and retrospective interviews of relatives were used. CONCLUSIONS: The suicidal process in suicide victims diagnosed with adjustment disorder appears to be short and rapidly evolving without any prior indications of emotional or behavioural problems. The importance of assessing the suicidal risk in patients diagnosed with adjustment disorder is underlined.

Adjustment Disorders↗
PubMed2005

Anaesthesia for patients with mood disorders.

PURPOSE OF REVIEW: Treatment of patients with mood disorders has changed over the past few years. It is not always clear how the anaesthesiologist has to incorporate these antidepressants and mood stabilizers in premedication or even how to anticipate any interaction with anaesthetic technique. RECENT FINDINGS: The older generation of antidepressants (tricyclic antidepressants, monoamine oxidase inhibitors) is seldom used nowadays. Actually, treatment with selective serotonin-reuptake inhibitors, serotonin noradrenaline-reuptake inhibitors, noradrenaline-reuptake inhibitor, noradrenergic and specific serotonin antidepressants, or noradrenaline- and dopamine-reuptake inhibitors is common practice. Combination with atypical antipsychotics and newer antiepileptics is suggested as an add-on therapy or as monotherapy, while lithium and valproate therapy is still the first choice in bipolar mood stabilization. Electroconvulsive therapy is still used in therapy-resistant forms of depression; however, the anaesthesia technique herein has been increasingly well described in the last years. Electroencephalogram-derived monitoring such as bispectral index (BIS) can be used as a tool to predict seizure duration. Intoxications with these newer agents are not infrequent and deserve specific attention. In particular, serotonin syndrome is a life-threatening condition that requires great care by the anaesthesiologist. The chronic use of antidepressants does affect the anaesthetized patient: hypotension, arrhythmias, changed thermoregulation, altered postoperative pain, differences in surgical stress response and postoperative confusion. However, it is advised to continue these drugs in the perioperative period. SUMMARY: Discontinuation of treatment with the new antidepressants in the perioperative period is not advised. Intoxication with the newer drugs appears to be safer. The anaesthesiologist must pay attention to serotonin syndrome. Electroconculsive therapy has gained renewed attention.

Journal Article↗
PubMed2004

Cognitive neuroactivation using SPECT and the Stroop Colored Word Test in patients with diffuse brain injury.

Psychomotor slowing in patients with diffuse brain injury frequently underlies impaired cognitive performance on neuropsychological tests, for example, the Stroop Colored Word test. The aim of the present study was to determine the neural basis associated with performance on the Stroop interference subtask in patients with diffuse brain injury. We hypothesized that patients would be slower than healthy controls, and that this would be associated with brain activations other than those seen in healthy subjects. Brain perfusion, using a split-dose activation paradigm with single photon emission tomography (SPECT) and the Stroop test, was assessed in 9 patients with diffuse brain injury. The Stroop interference score was calculated as a behavioral parameter, and functional imaging data were analyzed with statistical parametrical mapping (SPM99) to determine significant voxel-wise differences of activation between the control and the activation condition. Patients were impaired on the interference subtask of the Stroop test. Comparison of the SPECT data obtained during the activation condition with those obtained during the control condition by means of SPM showed significant activations in the left inferior parietal lobe, the right anterior cingulate extending into the right middle frontal gyrus and the right caudate, and the left posterior cingulate cortex. Patients with diffuse brain injury were slower than healthy controls on the interference subtask of the Stroop test, suggesting difficulty with resistance to distractions. This finding was associated with activation effects in posterior (mainly parietal) brain areas in addition with activation of previously observed anterior (mainly anterior cingulate) brain regions.

Adult↗
PubMed2004

Application of a neuropsychological activation probe with SPECT: the 'Tower of London' task in healthy volunteers.

BACKGROUND: Human planning is a complex mental process that may be evaluated by the 'Tower of London' (TOL) task, which includes setting up and maintaining multiple subgoals at the same time. Although positron emission tomography and functional magnetic resonance imaging have provided reliable data on the recruitment of a neural network engaged in planning tasks, the experimental settings of these studies cannot be applied in clinical conditions. Hence, this study reports on the TOL task under classical neuropsychological test conditions using single photon emission computed tomography (SPECT) activation in 10 healthy subjects. METHODS: Participants first performed a control task and then an activation task, i.e., the TOL planning task In the planning task, subjects were required to change, in the minimum number of moves possible, an initial arrangement of beads to match a goal arrangement. Subjects solved a set of eight TOL problems of increasing difficulty. A control task was designed such that it eliminates planning abilities, which is the process of interest. Planning times and accuracy were measured as performance parameters and functional imaging data were analysed with statistical parametric mapping (SPM99) to determine significant voxel-wise activations between the planning task and the control task. RESULTS: Both overall and for each difficulty level, measures of accuracy were within the normal range. Similar results were found for the overall thinking time and thinking times of each difficulty level. That is, performance of the healthy subjects during the TOL task replicated the typical pattern of results found with appropriate control samples in the literature. Also, activation of the right prefrontal cortex was consistent with other functional imaging results, thereby validating the use of the TOL task in a SPECT activation paradigm. CONCLUSIONS: Based on the present study it may be concluded that the close resemblance of the test conditions of the SPECT activation procedure with those of the TOL task in the investigation room constitutes a major advantage for future application of the SPECT activation procedure in clinical conditions.

Adult↗
PubMed2004

Comparison of cortical 5-HT2A receptor binding in bulimia nervosa patients and healthy volunteers.

OBJECTIVE: Bulimia nervosa has been associated with alterations in central serotonergic (5-HT) function. This study investigated iodine-labeled 4-amino-N-[1-[3-(4-fluorophenoxy) propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenzamide ((123)I-5-I-R91150) binding to the 5-HT(2A) receptor in the brain by using single photon emission computed tomography in acutely ill bulimia nervosa patients. METHOD: Cortical (123)I-5-I-R91150 binding in 10 normal-weight patients with bulimia nervosa, purging type, was compared with that of 11 healthy volunteers. RESULTS: The 5-HT(2A) binding index of the bulimia nervosa patients, with and without correction for age, was not significantly different from that of the comparison group. CONCLUSIONS: As a group, acutely ill bulimia nervosa patients cannot be discriminated from healthy subjects on the basis of cortical (123)I-5-I-R91150 binding to the 5-HT(2A) receptor.

Acute Disease↗
PubMed2003

The prefrontal cortex: insights from functional neuroimaging using cognitive activation tasks.

This review presents neuroimaging studies which have explored the functional anatomy of a variety of cognitive processes represented by the prefrontal cortex (PFC). Overall, these studies have demonstrated that standard prefrontal neuroactivation tasks recruit a widely distributed network within the brain of which the PFC consistently forms a part. As such, these results are in keeping with the notion that executive functions within the PFC rely not only on anterior (mainly prefrontal) brain areas, but also on posterior (mainly parietal) brain regions. Moreover, intervention of similar brain regions in a large number of different executive tasks suggests that higher-level cognitive functions may best be understood in terms of an interactive network of specialised anterior as well as posterior brain regions.

Animals↗
PubMed2003

Estimates of regional cerebral blood flow and 5-HT2A receptor density in impulsive, aggressive dogs with 99mTc-ECD and 123I-5-I-R91150.

Impulsive aggression in dogs has an important impact on human public health. Better insight into the pathophysiology of this phenomenon could lead to more adequate diagnosis and treatment. Indirect in vivo research on peripheral body fluids and post-mortem studies in impulsive animals and humans indicate a deficient serotonergic system in general and disturbances in the serotonin-2A (5-HT2A) receptor in particular. In this study, brain perfusion and the 5-HT2A receptors were examined in impulsive, aggressive dogs, in comparison with a group of normally behaving animals. In order to decide which dogs to include in this study, owners were asked to describe the general behaviour of the dogs, the circumstances in which aggression occurred and their conduct during aggressive acts. Finally, 19 dogs were retained for this study, showing, according to different behavioural specialists, disinhibited dominance aggression. Functional imaging studies were performed on all these dogs. Single-photon emission tomography (SPET) was used to measure regional brain perfusion using technetium-99m labelled ethyl cysteinate dimer (ECD). The 5-HT2A receptor binding properties were investigated using the selective radioligand iodine-123 labelled 5-I-R91150. A significant increase in uptake of the 5-HT2A radioligand was noted in all cortical areas. No significant alterations were found in regional cortical perfusion, indicating that the increased binding index was not a consequence of increased tracer delivery. This study supports a role for the serotonergic system in canine impulsive aggression.

Aggression↗