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A Rabavilas

Publications and source records attributed to A Rabavilas.

11 recordsLinked to original sources
PubMed2005

Occupational abilities and performance scale--reliability-validity assessment factor analysis.

BACKGROUND: This article presents a study of the Occupational Abilities and Performance Scale (OAPS), developed for administration to schizophrenic patients. The reliability and validity of the OAPS has been evaluated. METHOD: A total of 174 schizophrenic patients who participated in the Psychosocial and Vocational Rehabilitation Unit (PVRU) of the University Mental Health Research Institute (UMHRI) in Athens were assessed. The OAPS is conducted at entry and after 18 months, when the client has completed training. RESULTS: The results of the reliability analysis showed very good internal consistency, with high split-half reliability as well as test-retest reliability and inter-rater agreement. The scale was also found to have good predictive validity, as well as concurrent validity. Finally, factor analysis with principal components extraction method was performed in order to assess the construct validity of the scale. CONCLUSIONS: The results of factor analysis supported the conclusion of good reliability and validity of the OAPS and revealed the existence of five components, each correlated with a set of the original items.

Adult↗
PubMed2001

Impaired P600 in neuroleptic naive patients with first-episode schizophrenia.

Deficits of working memory (WM) are recognized as an important pathological feature in schizophrenia. Since the P600 component of event related potentials has been hypothesized that represents aspects of second-pass parsing processes of information processing, and is related to WM, the present study focuses on P600 elicited during a WM test in drug-naive first-episode schizophrenics (FES) compared to healthy controls. We examined 16 drug-naive first-episode schizophrenic patients and 23 healthy controls matched for age and sex. Compared with controls schizophrenic patients showed reduced P600 amplitude on left temporoparietal region and increased P600 amplitude on left occipital region. With regard to the latency, the patients exhibited significantly prolongation on right temporoparietal region. The obtained pattern of differences classified correctly 89.20% of patients. Memory performance of patients was also significantly impaired relative to controls. Our results suggest that second-pass parsing process of information processing, as indexed by P600, elicited during a WM test, is impaired in FES. Moreover, these findings lend support to the view that the auditory WM in schizophrenia involves or affects a circuitry including temporoparietal and occipital brain areas.

Acoustic Stimulation↗
PubMed2001

Abnormal P600 in heroin addicts with prolonged abstinence elicited during a working memory test.

The P600 component of event-related potentials, believed to be generated by anterior cingulate gyrus and basal ganglia, is considered as an index of aspects of second-pass parsing processes of information processing, having much in common with working memory (WM) systems. Moreover, dysfunction of these brain structures as well as WM deficits have been implicated in the pathophysiology of opioid addicts. The present study is focused on P600 elicited during a WM test in twenty heroin addicts with prolonged abstinence compared with an equal number of healthy controls. The results showed significantly prolonged latencies at right hemisphere, specifically at Fp2 abduction. Moreover, memory performance of patients did not differ from that of normal controls. These findings may indicate that abstinent heroin addicts manifest abnormal aspects of second-pass parsing processes as are reflected by the P600 latencies, elicited during a WM test. Additionally, the P600 might serve as a valuable investigative tool for a more comprehensive understanding of the neurobiological substrate of drug abuse.

Adult↗
PubMed2000

Olanzapine and obsessive-compulsive symptoms.

Clozapine and risperidone have been implicated in the development of obsessive-compulsive symptoms. We present three cases in which olanzapine caused a significant exacerbation of obsessive-compulsive symptoms in schizophrenia (two cases) and obsessive-compulsive disorder (one case).

Adult↗
PubMed2000

Simulated generation of evoked potentials components using networks with distinct excitatory and inhibitory neurons.

Long latency evoked potentials (EP's) are electrical potentials related to brain information processing mechanisms. In this paper, three-layered neurophysiologically based artificial neural network model is presented whose neurons obey to Dale's law. The first two layers of the network can memorize and recall sparsely coded patterns, oscillating at biologically plausible frequencies. Excitatory low-pass filtering synapses, from the second to the third layer, create evoked current dipoles, when the network retrieves memories related to stimuli. Based on psychophysiological indications, simulated intracranial dipoles are straightforwardly transformed into long latency EP components such as N100 and P300 that match laboratory-measured scalp EP's.

Biomedical Engineering↗
PubMed1991

Noxious heat hyperalgesia test instrument.

A simple feedback thermode has been developed to quantify cutaneous hyperalgesia to noxious heat. A noxious temperature set between 42 degrees C and 60 degrees C is applied to a test site by the subject. A resettable impedance timing circuit measures the contact duration to +/- 0.01s. Despite site-to-site, inter- and intra-subject variability, the test sensitivity is enhanced by comparing affected and corresponding normal skin in the same subject. This test strategy was used in 55 subjects in whom topical 0.025 to 0.05% capsaicin application provoked hyperalgesia on the forearm and foot. Capsaicin-treated sites showed a significant reduction of 52 degrees C withdrawal latency (0.51-0.77 x normal mean; P less than 0.05). The device has been tested clinically in patients with diabetic neuropathy who had hypersensitivity to pinprick on one foot. A significant 42% difference was found between corresponding contralateral sites (P less than 0.05). These data suggest that even mild hyperalgesia is detectable using this instrument. It provides an objective measure of hyperalgesia which can be used to assess changes in nociceptive acuity.

Capsaicin↗
PubMed1983

Neuroses and ABO blood types.

Determination of ABO blood types was carried out in 72 (35 female and 37 male) patients with obsessive-compulsive neurosis, 73 (35 female and 38 male) patients with phobic neurosis, 75 (54 female and 21 male) patients with hysteria and a random sample of 600 individuals (268 female and 332 male) drawn from the general population. Results provide evidence of: (1) a positive association between obsessive-compulsive neurosis and blood type A and a corresponding negative association between the former and blood type O; (2) a positive association between phobic neurosis and blood type O and a corresponding negative association between the former and blood type A, and (3) a positive association between hysteria and blood type A and a corresponding negative association between the former and blood type O. Moreover, sex does not appear to modify the ABO blood type distribution in our patients with obsessive-compulsive neurosis, phobic neurosis or hysteria. These findings might be considered as supporting the view that hereditary factors in the neurotic individual may influence the clinical form of his neurosis.

ABO Blood-Group System↗
PubMed1980

Obsessional personality traits and ABO blood types.

The relation of ABO blood types to obsessional personality traits, as measured by the Leyton Obsessional Inventory (LOI), was studied in a sample of 600 normal individuals. High scorers of the LOI trait portion demonstrated a significantly lower incidence of phenotype O and a significantly higher incidence of phenotypes AB, A and B, taken together, compared to those of a general population sample and the entire study group. Findings of the present study, in conjunction with previous findings concerning a lower incidence of phenotype O and a higher incidence of phenotype A in obsessive compulsive patients, could be interpreted as indicating that phenotype O may be associated with personality traits hindering the development of obsessive-compulsive symptomatology.

ABO Blood-Group System↗