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Biomedical subjects

J M Cañive

Publications and source records attributed to J M Cañive.

7 recordsLinked to original sources
PubMed2003

Interpreting abnormality: an EEG and MEG study of P50 and the auditory paired-stimulus paradigm.

Interpretation of neurophysiological differences between control and patient groups on the basis of scalp-recorded event-related brain potentials (ERPs), although common and promising, is often complicated in the absence of information on the distinct neural generators contributing to the ERP, particularly information regarding individual differences in the generators. For example, while sensory gating differences frequently observed in patients with schizophrenia in the P50 paired-click gating paradigm are typically interpreted as reflecting group differences in generator source strength, differences in the latency and/or orientation of P50 generators may also account for observed group differences. The present study examined how variability in source strength, amplitude, or orientation affects the P50 component of the scalp-recorded ERP. In Experiment 1, simulations examined the effect of changes in source strength, orientation, or latency in superior temporal gyrus (STG) dipoles on P50 recorded at Cz. In Experiment 2, within- and between-subject variability in left and right M50 STG dipole source strength, latency, and orientation was examined in 19 subjects. Given the frequently reported differences in left and right STG anatomy and function, substantial inter-subject and inter-hemispheric variability in these parameters were expected, with important consequences for how P50 at Cz reflects brain activity from relevant generators. In Experiment 1, simulated P50 responses were computed from hypothetical left- and right-hemisphere STG generators, with latency, amplitude, and orientation of the generators varied systematically. In Experiment 2, electroencephalographic (EEG) and magnetoencephalographic (MEG) data were collected from 19 subjects. Generators were modeled from the MEG data to assess and illustrate the generator variability evaluated parametrically in Experiment 1. In Experiment 1, realistic amounts of variability in generator latency, amplitude, and orientation produced ERPs in which P50 scoring was compromised and interpretation complicated. In Experiment 2, significant within and between subject variability was observed in the left and right hemisphere STG M50 sources. Given the variability in M50 source strength, orientation, and amplitude observed here in nonpatient subjects, future studies should examine whether group differences in P50 gating ratios typically observed for patient vs. control groups are specific to a particular hemisphere, as well as whether the group differences are due to differences in dipole source strength, latency, orientation, or a combination of these parameters. Present analyses focused on P50/M50 merely as an example of the broader need to evaluate scalp phenomena in light of underlying generators. The development and widespread use of EEG/MEG source localization methods will greatly enhance the interpretation and value of EEG/MEG data.

Adult↗
PubMed1999

Divalproex in posttraumatic stress disorder: an open-label clinical trial.

Posttraumatic stress disorder (PTSD) is characterized by intrusive, avoidance, and hyperarousal symptoms. This study was conducted to investigate the effectiveness of divalproex in reducing PTSD symptoms, depression, and anxiety in patients with PTSD. Sixteen patients with a DSM-IV diagnosis of PTSD at the Albuquerque VAMC outpatient PTSD treatment program received an open-label trial of divalproex. The patients were evaluated at baseline and at 8 weeks by a trained rater using the Clinician Administered PTSD Scale (CAPS), the Hamilton Rating Scale for Depression (HAM-D) and the Hamilton Rating Scale for Anxiety (HAM-A). Plasma valproate levels were measured at the 8-week post-treatment assessment. Three patients stopped the medications due to side effects. Intrusion and hyperarousal symptoms decreased significantly, while no significant change was seen in avoidance/numbing symptoms. Depressive symptoms, as measured by the HAM-D, unexpectedly decreased at post-treatment assessment. HAM-A scores also decreased significantly. Controlled trials are needed to further study the efficacy of divalproex in the treatment of PTSD.

Adult↗
PubMed1998

Bupropion treatment in veterans with posttraumatic stress disorder: an open study.

This study was designed to investigate the efficacy of the antidepressant drug bupropion in the treatment of posttraumatic stress disorder (PTSD). Seventeen male combat veterans with chronic PTSD were treated with bupropion in an open-label fashion for 6 weeks. Patients were evaluated with the Clinical Global Impressions Scale for Improvement (CGI-I) at follow-up and rated blindly at baseline and posttreatment with the Clinician Administered PTSD Scale (CAPS), the Hamilton Rating Scale for Depression (HAM-D), and the Hamilton Rating Scale for Anxiety. Three patients discontinued bupropion prematurely because of side effects. Of the remaining 14 patients, 10 were classified as treatment responders by the CGI-I. HAM-D scores decreased significantly from baseline to follow-up. The improvement seen in hyperarousal symptoms was significant but was less significant than the change in depressive symptoms. There was no significant change in Intrusion, Avoidance, or total CAPS scores. It was concluded that bupropion was well tolerated. Patients who had experienced sexual dysfunction with selective serotonin reuptake inhibitors reported no complaints during bupropion treatment. Bupropion decreased depressive symptoms and most patients reported global improvement, although PTSD symptoms remained mostly unchanged. Controlled trials should further clarify the role of bupropion in the treatment of PTSD.

Aged↗
PubMed1998

Spontaneous brain magnetic activity in schizophrenia patients treated with aripiprazole.

This magnetoencaphalographic (MEG) study was conducted as part of a multicenter clinical trial to study the efficacy of aripiprazole. Participants included 5 DSM-IV schizophrenia subjects and 10 age-matched normal controls. The schizophrenia subjects underwent a second MEG recording after 8 weeks of open-label treatment with aripiprazole. Overall, control subjects showed no abnormal spontaneous magnetic brain activity. At washout, 3 patients showed increased delta and theta activity along with paraxosymal bitemporal slow waves. In 2 of these patients, the slow waves were generated in the superior temporal plane, as determined by dipole modeling. In the third patient, the slow waves appeared to have been generated at multiple regions throughout the temporal and inferior parietal lobes. As a group, schizophrenia patients, when compared with normal controls, demonstrated significant decreases in alpha peak frequency and power. Following treatment, aripiprazole had a significant normalizing effect on delta and theta activity. Patients on aripiprazole continued to demonstrate significant abnormalities in alpha frequency and power.

Adult↗
PubMed1996

Family psychoeducational support groups in Spain: parents' distress and burden at none-month follow-up.

Forty-one mothers and twenty-seven fathers agreed to participate in a 6-week, low-cost, multiple-family psychoeducational intervention in Spain. Their knowledge acquisition, subjective distress, annoyance at patient's behavior, perception of social impact of the patient's illness, expectations about patient's recovery, and family burden were measured before and after the intervention and at 9-month follow-up. Ninety-three percent of the fathers and 78% of the mothers attended four or more classes. Although parents acquired a significant amount of knowledge about the illness, no significant score differences were found immediately after the intervention or at follow-up in the other measures. However, significant father-mother differences were revealed. Compared with mothers, fathers were more optimistic throughout the study about the outcome of the illness, became more aware of the social and financial impact of the illness on the family, and reported feeling less annoyed by the patient's behavior at follow-up. The results indicate that low-cost psychoeducational multiple family groups alone do not decrease family distress and burden. These findings also suggest that psychoeducational interventions need to consider differences in gender and family roles and underline the importance of engaging fathers in treatment.

Adaptation, Psychological↗
PubMed1996

Magnetoencephalographic assessment of spontaneous brain activity in schizophrenia.

Magnetoencephalography (MEG) offers an attractive alternative to electroencephalography (EEG) in the assessment of psychiatric patients. In this study, a whole-head biomagnetometer equipped with 122 super-cooled sensors was used to assess spontaneous neuromagnetic activity in 11 unmedicated schizophrenic patients and 8 schizophrenic patients medicated for more than 8 weeks with novel antipsychotics (5 of whom were initially studied as part of the unmedicated group). Ten normal (nonpsychiatric) controls were also examined. For each subject, 5 minutes of data were collected in an eyes-closed state. Data were visually inspected for gross MEG abnormalities, and average power spectra were calculated for the data at each sensor. No gross abnormalities were identified for control subjects. One unmedicated schizophrenic patient showed epileptiform sharp waves, and 4 showed abnormal slow waves. No gross MEG abnormalities were found for the medicated schizophrenic group (which included 3 patients who had previously shown slow waves in the unmedicated state). Spectral analyses showed that the schizophrenia patients demonstrated lower alpha power and peak frequency than controls. The data are interpreted within the context of previously reported magnetic resonance abnormalities of the thalamus.

Adult↗