Biomedical subjects

M I López-Ibor Alcocer

Publications and source records attributed to M I López-Ibor Alcocer.

3 recordsLinked to original sources

PubMed1999

Regional cerebral blood flow in obsessive-compulsive patients with and without a chronic tic disorder. A SPECT study.

The main goal of the present study was to explore whether regional cerebral blood flow (rCBF) differs between obsessive-compulsive disorder (OCD) patients without chronic motor tic disorder and those OCD patients with a comorbid chronic tic disorder. Twenty-seven patients suffering from OCD (DSM-IV criteria), including 7 OCD patients who met DSM-IV criteria for simple chronic motor dic disorder, and 16 healthy volunteers were examined at rest using a high resolution SPECT. Seven regions of interest (ROIs) were manually traced and quantified as a percentage of the mean cerebellar uptake. Severity of obsessive-compulsive symptoms (OCS), anxiety and depressive symptoms and presence of motor tics were assessed with the Y-BOCS, HRS-A, HRS-D, MADRS, and Yale Global Tics Severity Scale, respectively. We found a significant relative decrease in rCBF in OCD patients without motor tics compared to healthy volunteers in the right orbitofrontal cortex (OCD without tics = 0.87; healthy volunteers = 0.94; p = 0.02). No significant differences in rCBF were seen when OCD patients with and without chronic tics were directly compared. A lower severity of OCS in OCD patients with chronic tics was found. These results are consistent with previous functional neuroimaging studies at rest that have widely involved the orbitofrontal cortex in the pathophysiology of the OCD. However, our results do not support the idea that OCD patients with chronic tics may constitute a biological subgroup within the OCD.

Adult↗

PubMedDate not supplied

[New advances in neuroimaging in the diagnosis of obsessive-compulsive disorder].

Brain-imaging research provides evidence to suggest that the underlying disfunction in Obsessive-Compulsive Disorder (OCD) is likely to be in the prefrontal cortex-basal ganglia thalamic circuit rather then in any one single brain region. Early computerized tomography and magnetic resonance imaging studies have shown morphological changes in the basal ganglia. Now more sophisticated techniques are enhancing the information available, specially with regard to the caudate nucleus. The serotonergic hypothesis remains a necessary but not sufficient explanation for the pathogenesis of OCD. Most evidence remains focussed on the basal ganglia and on a 5-HT/dopamine inter-relationship. Given the basal ganglia receive such rich innervation from both 5-Th and dopamine neurones, it has been postulated that OCD is subserved by a neuronal dysfunction in the basal ganglia and orbitofrontal cortex circuit. Combining behavioural challenge with brain imaging may be a better approach to capturing brain function while patients with OCD and control subjects are actually observed. Using this techniques has made it possible to identified changes in response to treatment, whether the treatment is pharmacological or behavioural. However, there are not data enough that allow us to understand the anatomical, physiological and chemical mechanisms implicated in OCD.

Basal Ganglia↗

PubMedDate not supplied

[Obsessive-compulsive disorder and depression].

Obsessive-compulsive disorders (OCD) are unique among the anxiety disorders. They have many characteristics in common with depressive disorders, both from clinical as well from psychopathological and neurochemical perspectives. The clinical response to serotonergic antidepressants is also similar. But, in spite of the common aspects, there are at every level important peculiarities which definitively differentiate OCD from depressive disorders. We present data on neuroendocrinological challenges and on brain regional blood flow measured with the SPECT. OCD patients not fulfilling diagnostic criteria for depression have an exaggerated response to a serotonergic challenge, measured by the increase in Prl, Cor and GH plasma concentrations when compared to controls. The differences are higher when controlling for the presence of depressive (subsyndromal) symptoms. Patients with OCD and comorbid depression have a blunted response to the CMI challenge. SPECT shows an increased blood flow in basal ganglia and hippocampus on the left side. In the presence of a comorbid depression, the regional brain blood flow shows a marked decrease in wide range of brain regions. Therefore, the presence of depressive symptoms and even more of diagnostic criteria for major depression significantly changes neuroendocrinological challenge tests and regional blood flow in OCD patients, making them look like depressive patients. Although depressive symptoms are present in many OCD patients and that there is a significant comorbidity between OCD and depressive disorders, we believe that they can be differentiated from the biological point of view. Furthermore, the association of depressive symptoms and of depression diagnostic criteria to OCD masks the biological finding, neurochemical and of brin regional blood flow, of OCD. This is an important factor to be considered when carrying out research in this field.

Adrenocorticotropic Hormone↗