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Biomedical subjects

P A Keenan

Publications and source records attributed to P A Keenan.

At least 19 recordsLinked to original sources
PubMed2001

Prefrontal cortex as the site of estrogen's effect on cognition.

The hippocampus has long been presumed the primary site of action of estrogens on cognition; and explicit memory is considered the cognitive function most vulnerable to menopausal loss of estrogen. We hypothesize instead that the prefrontal cortex and its neural circuitry are prime mediators of estrogen's role in cognition. We also propose that previously reported menopausal cognitive decline, presumed to be hippocampally mediated, may be secondary to executive dysfunction. We used a cross sectional design to compare the performance of nine menopausal women on hormone replacement therapy (HRT) and 10 menopausal women with no prior exposure to HRT on a battery of neuropsychological tests. The battery was comprised primarily of tests of memory and executive functioning. Executive functioning is mediated by the frontal lobes and encompasses working memory, directed attention, the inhibition of inappropriate responses, cognitive set switching, and behavioral monitoring. Unlike most previous studies, we used a memory measure that yields multiple scores reflecting various problem-solving strategies and error types, thus isolating spared and impaired cognitive processes. Results yielded both qualitative and quantitative evidence for disruption of cognitive processes subserved by the frontal lobes rather than the hippocampus: 1) despite intact free recall on a list-learning task (CVLT), untreated menopausal women were relatively impaired in correctly recognizing words previously learned and distinguishing them from items not on the list (discriminability), 2) untreated women also had difficulty inhibiting inappropriate responses in the form of perseverative errors, and 3) the non-HRT group consistently performed worse on the N-back test of working memory. The prefrontal cortex is critical for intact working memory and estrogen enhances performance on working memory tasks. In conclusion, this study provides preliminary evidence for executive dysfunction in untreated menopausal women as women with HRT outperformed women without HRT on tests requiring directed attention, inhibition of inappropriate responses, and cognitive set switching.

Cognition↗
PubMed2001

Rapid hiv testing in urban outreach: a strategy for improving posttest counseling rates.

In 1998, 48% of persons who had HIV testing at publicly funded sites in the United States failed to return for test results and posttest counseling. Opportunities for timely HIV therapy were lost; valuable resources were wasted. This study tested the hypothesis that rapid HIV testing enables a high percentage of high-risk outreach clients to learn their serostatus. We did on-site counseling and rapid HIV testing at community-based organizations (e.g., chemical dependency programs, homeless shelters) in North Minneapolis. The project tested 735 persons. All but one (99.9%) learned their HIV serostatus. African Americans made up 79% of subjects. Rapid testing has a role to play in HIV outreach. It is useful in populations who are at high risk of HIV infection, who currently are not accessing HIV testing, and who have high failure to return rates. Future developments in rapid testing technology will make this testing option more convenient and cost-effective.

AIDS Serodiagnosis↗
PubMed1999

Neuropsychological deficits associated with antiphospholipid antibodies.

Neurologic events associated with antiphospholipid antibodies (aPAs) include transient ischemic attack, stroke, and vascular dementia in individuals much younger than is typically observed with these disorders. The present study evaluated 27 non-elderly adults with aPAs but without concurrent disease processes or history of neurologic event and 27 age- and education-matched controls. MANOVA (p <.01) indicated group differences in executive functioning, verbal learning and memory, and visuospatial ability. In contrast, gross attentional processes and fine motor skills appeared unaffected by the <?Pub Caret>syndrome. Moreover, the frequency of impaired neuropsychologic performance was greater among individuals with aPAs than among controls (p <.01). The presence of cognitive deficits in otherwise asymptomatic patients with aPAs indicates a preclinical phase of neurologic involvement and may prove to be the most sensitive markers of the syndrome.

Antibodies, Antiphospholipid↗
PubMed1998

Explicit memory in pregnant women.

OBJECTIVE: The study was conducted to systematically investigate previous anecdotal reports of memory decline during pregnancy. STUDY DESIGN: We used a longitudinal design to investigate memory in women throughout pregnancy and in the postpartum period. Closely matched, nonpregnant women were similarly studied at equivalent intervals. We also assessed degree of depression and anxiety. RESULTS: There was a significant time-by-group interaction (P < .01) for both immediate and delayed recall of paragraph length material. Contrasts showed a significant decline in memory for the pregnant group from the second to the third trimester (P < .01). No significant changes in memory were noted for the control group. The pregnant women scored higher on both depression and anxiety scales; however, somatic rather than cognitive items accounted for the elevated scores. Fluctuations in mood and memory did not coincide. CONCLUSION: There is a pregnancy-related decline in memory, which is limited to the third trimester. The decline is not attributable to depression, anxiety, sleep deprivation, or other physical changes associated with pregnancy.

Adult↗
PubMed1996

The effect on memory of chronic prednisone treatment in patients with systemic disease.

There have been no systematic investigations of the effects of glucocorticoid treatment on memory in a clinical population despite experimental and clinical evidence that such treatment could cause memory disturbance. We conducted both cross-sectional and longitudinal studies. In Study 1, we administered tests of both hippocampal-dependent explicit memory and hippocampal-independent implicit memory to twenty-five prednisone-treated patients with systemic disease without CNS involvement and 25 matched clinical controls. All treated patients were taking doses of 5 to 40 mg of prednisone daily for at least 1 year. The glucocorticoid-treated group performed worse than the controls on tests of explicit memory, but the groups did not differ on the implicit memory task. Multiple regression analyses suggested that elderly patients are more susceptible to memory impairment with less protracted treatment. The results of Study 2, a prospective, longitudinal study of the effects of prednisone on memory across 3 months of therapy, suggest that even acute treatment can adversely affect memory. The observed alteration in memory was not secondary to inattention, affective disturbance, generalized global cognitive decline, or severity of disease. Results reported here, combined with previous clinical and experimental reports, indicate that the risk of memory impairment should be carefully considered before initiating treatment with glucocorticoids. Conversely, use of glucocorticoids should be considered in the differential diagnosis of memory loss. Finally, the potential benefit of anti-inflammatory treatment in Alzheimer's disease might be counterbalanced by possible iatrogenic memory impairment, at least when synthetic glucocorticoids are considered.

Adult↗
PubMed1995

Menstrual phase-independent retrieval deficit in women with PMS.

Memory and attention were evaluated in 19 women with prospectively documented premenstrual syndrome (PMS) and 17 women without PMS. Testing occurred during the late luteal and follicular phases of the menstrual cycle. Estrogen, progesterone, and FSH levels were obtained on testing days for 23 of the women, while mood measures were obtained for all of the women. Repeated measures analysis of variance yielded significant group differences on recall measures, with no differences noted on recognition indices. No significant session or interaction effects were observed. This pattern of results suggests impaired retrieval of learned information coincident with intact encoding. No significant effects were noted for any of the nonverbal memory, attention, or other neurocognitive variables. The obtained data support previous findings of a mild, phase-independent memory impairment in women with PMS and also contribute to a better understanding of the component memory processes involved.

Adult↗
PubMed1994

Visuoperceptual-spatial ability and visual memory in vascular dementia and dementia of the Alzheimer type.

This study investigated the relationship between visuoperceptual ability and visual memory in dementia. Twenty individuals with probable dementia of the Alzheimer type, 24 individuals with probable vascular dementia, and 20 healthy, elderly adults underwent neuropsychological evaluation. Hierarchical multiple regression analyses suggested that perceptual organization skills contributed to a significant amount of the variance in novel, but not famous, face recognition. This finding was most robust in the clinical groups. Causality cannot be attributed from this regression model. Results suggest, however, that visual processing deficits are more strongly related to the memory process at the time of encoding rather than during recognition of remote information.

Aged↗
PubMed1992

Non-migraine headache across the menstrual cycle in women with and without premenstrual syndrome.

Fluctuation of estrogen levels across the menstrual cycle influences migraine headache. In this study, 53 women documented prospectively the incidence and severity of headache daily for an average of three menstrual cycles. Seven of the women met the criteria established by the International Headache Society for migraine with or without aura, while the remaining 46 women failed to do so. Chi-square analysis revealed that, overall, the incidence of non-migraine headache was dependent on day of the cycle (chi 2 [1,66] = 247.7, p < 0.001), with more headaches occurring during the perimenstrual phase. The 46 women without migraine were further classified according to NIMH criteria into PMS (n = 26) and non-PMS groups (n = 20). An association between headache and menstrual cycle phase was noted for both groups (p < 0.001), although the incidence of severe headache was greater for the PMS women, during both the perimenstrual and intermenstrual phases. Both groups experienced an increase in severe headaches during the perimenstrual phase. The PMS women peaked on the day prior to menstruation, while the non-PMS women peaked on the first day of menstruation. There did not appear to be an overall difference in the reporting of mild headache across the cycle between women with or without PMS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Clinical and neuropsychological effects of desipramine in children with attention deficit hyperactivity disorder.

Desipramine is a tricyclic antidepressant with demonstrated efficacy for some children with attention deficit hyperactivity disorder (ADHD). In this controlled study, clinical improvement was noted in a group of 12 ADHD children. There also were neuropsychological effects associated with desipramine treatment: a small but significant decline in motor performance and an improvement in long-term verbal memory. The decline in motor performance may be of only limited clinical significance, but it is an effect that desipramine seems to share with other tricyclic antidepressants. The improvement in memory performance is an effect it shares with the psychostimulants.

Affect↗
PubMed1989

Hemispheric asymmetry in the processing of high and low spatial frequencies: a facial recognition task.

The research investigated the relationship between spatial frequency and visual field in a facial recognition task. Faces of neutral affect (Ekman, 1979) were tachistoscopically presented to the right or left visual field. The faces were presented alone, or masked with square wave gratings of 1, 24, or 48 cycles/degree, for a duration of 10 msec. Accuracy in recognizing each target face from a group of five served as the dependent measure. Subjects were 15 males and 15 females. ANOVA results included a frequency x visual field interaction effect (p less than .001). As was hypothesized, LVF errors were highest in the absence of low spatial frequencies, while RVF errors were highest when a higher range of spatial frequencies was removed. These results confirm that the hemispheres show a differential efficiency in processing high and low spatial frequency information in faces. They also offer empirical evidence to support the clinical findings that both hemispheres contribute to facial recognition.

Adult↗
PubMed1985

Successful migraine prophylaxis with naproxen sodium.

Naproxen sodium, a potent inhibitor of prostaglandin biosynthesis and platelet aggregation, was studied for efficacy in migraine prophylaxis in a randomized, double-blind, placebo-controlled, crossover trial. On naproxen treatment, 52% of the patients had no severe headaches, whereas 19% had no severe headaches during placebo. Naproxen sodium was much better than placebo when patients' diaries were reviewed for severity of attacks, nausea, vomiting, activity reduction, duration of headache, and decreased use of therapeutic medication. The degree of platelet inhibition did not correlate with efficacy in preventing headache. Naproxen sodium can be recommended as a drug of first choice for migraine prevention.

Adult↗
PubMedDate not supplied

Psychological aspects of premenstrual syndrome. I: Cognition and memory.

Fourteen women with PMS and ten without PMS were evaluated with a battery of neuropsychological tests during the follicular and late luteal phases of two consecutive menstrual cycles. Classification was determined with NIMH diagnostic criteria and prospective record keeping. The results indicated that (1) the PMS women had significant difficulty in learning new material and this problem was not phase-dependent, (2) both groups performed better on a test of frontal lobe function during the follicular phase, and (3) mood did not account for any of the differences in cognitive functioning.

Adult↗
PubMedDate not supplied

Psychological aspects of premenstrual syndrome. II: Utility of standardized measures.

Depressed mood is a salient feature of Premenstrual Syndrome (PMS). Fourteen women with prospectively documented PMS and ten without PMS completed the short form of the Beck Depression Inventory (BDI) and the Zung Self-Rating Scale for Depression (Zung-D) during the follicular and late luteal phases of two consecutive menstrual cycles. The short form of the BDI assesses the more cognitive symptoms of depression, while the Zung-D identifies primarily vegetative symptoms. The short form of the BDI was sensitive to cyclic changes in the PMS women, while the Zung-D was not. The BDI items uniquely endorsed by the PMS women during the late luteal phase were pessimism, sense of failure, dissatisfaction, guilt, self-dislike, and indecision. The premenstrual dysphoria experienced by PMS women thus appears to be more cognitive than vegetative in nature. Finally, differential utility of standardized mood measures to detect premenstrual depression is suggested. The BDI proved to be the more sensitive measure.

Adult↗