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Lisa T Eyler

Publications and source records attributed to Lisa T Eyler.

12 recordsLinked to original sources
PubMed2007

Neurocognitive impairment in middle-aged and older adults with bipolar disorder: comparison to schizophrenia and normal comparison subjects.

BACKGROUND: The frequency, pattern, and correlates of neurocognitive impairment in older patients with bipolar disorder have received little study. We examined neurocognitive abilities in middle-aged and older adults with bipolar disorder to groups with schizophrenia or normal subjects, as well as the relation of neurocognition to clinical characteristics. METHOD: We administered a battery of neurocognitive and clinical measures to older (45-85 years) outpatients with bipolar disorder (n=67), schizophrenia (n=150), and normal comparison subjects (n=85). Within the bipolar group, we assessed the association between neurocognitive performance and psychiatric symptoms, quality of life, and medication status. RESULTS: The group with bipolar disorder differed on nearly all neuropsychological tests compared to normal subjects, with medium effect sizes. Bipolar patients as impaired as those with schizophrenia on half of the tests administered, and performed better on the remaining tests, with small effect sizes. Neurocognitive deficits in bipolar disorder group related to lower quality of life, but not to psychiatric symptom severity or duration of illness. LIMITATIONS: Samples were outpatients with mild-moderate symptoms, and findings may not generalize to acutely ill populations. We lacked data on illness history to examine the cumulative impact of psychopathology. CONCLUSIONS: Among clinically stable middle-aged and older outpatients, bipolar disorder was associated with substantial neurocognitive impairment, with a pattern that was somewhat distinct from that found in schizophrenia. Deficits in the bipolar group were not related to severity or duration of psychiatric symptoms, but were related to quality of life. Bipolar disorder often involve disabling and enduring cognitive impairments in older outpatients.

Age Factors↗
PubMed2006

The neural correlates of habituation of response to startling tactile stimuli presented in a functional magnetic resonance imaging environment.

Functional magnetic resonance imaging (fMRI) provides a means of identifying neural circuitry associated with startle and its modulation in humans. Twelve subjects who demonstrated eyeblink startle in the laboratory were recruited for an fMRI study in which they were scanned while presented with two identical runs consisting of alternating blocks of no stimuli and startling tactile stimuli. Together, behavioral and imaging data are consistent with a pattern of general cortical and thalamic activation induced by startling stimuli that shows habituation both across and within runs. From Run 1 to Run 2, both the eyeblink amplitude and the fMRI signal decreased. Within Run 1, there was a graded decrease in eyeblink amplitude and whole-brain fMRI signal across blocks of startling stimuli. A similar graded decrease was observed in the thalamus signal, as well. Thus, startling tactile stimuli initially induce widespread cortical and thalamic activity, perhaps mediated by the reticular activating system. The activity then habituates in a graded fashion with repeated presentations of the stimuli.

Adult↗
PubMed2006

Amygdala reactivity and mood-congruent memory in individuals at risk for depressive relapse.

BACKGROUND: According to cognitive diathesis-stress theories, a latent cognitive vulnerability to depression is activated by negative affect in individuals at risk for depressive relapse. This vulnerability can manifest as mood-congruent memory during sad mood and may involve amygdala response, which is implicated in memory for emotionally arousing stimuli. This study examined whether amygdala modulates memory for negatively valenced words before and after a sad mood induction in healthy individuals with and without a history of recurrent major depression. METHODS: Fourteen unmedicated remitted depressed (RD) and 14 matched never depressed (ND) individuals were scanned using functional magnetic resonance imaging (fMRI) while performing a self-referent encoding/evaluation task (SRET) preceding and following a sad mood challenge. After each SRET, participants' free recall was assessed. RESULTS: Following sad mood induction, bilateral amygdala response during encoding of valenced words predicted increased recall of negative self-referent words for a subset of RD participants. This association was not present before the sad mood induction and was not evident in individuals without a history of depression, regardless of mood state. CONCLUSIONS: These results are consistent with cognitive diathesis-stress theories and suggest a role for the amygdala in modulating mood-congruent memory during transient sad mood in individuals who are vulnerable to depression relapse.

Adult↗
PubMed2006

Verbal paired-associate learning by APOE genotype in non-demented older adults: fMRI evidence of a right hemispheric compensatory response.

Previous studies of episodic memory report a greater extent of blood-oxygenation-level-dependent (BOLD) response in non-demented older adults with the apolipoprotein E epsilon-4 (APOE epsilon4) allele than in those without the allele. We conducted a functional MRI study to investigate whether APOE genotype is related to brain response to verbal paired-associate encoding and consolidation, particularly in the right hemisphere, among non-demented older adults. Structurally segmented volumes and BOLD response were measured in 13 non-epsilon4 and 12 epsilon4 subjects. The epsilon4 group displayed greater activation than the non-epsilon4 group in multiple right hemisphere regions for previously encoded word pairs relative to fixation. Activation within manually outlined hippocampal regions of interest also displayed genotype-specific dissociations consistent with whole brain analyses. Furthermore, this differential BOLD response occurred in the presence of equivalent behavioral and neuropsychological performances as well as comparable hippocampal and overall structural segmentation volumes between groups. Results implicate a widely distributed and interconnected network of right hemisphere brain regions that may be involved in compensating for APOE epsilon4-related deficiencies associated with verbal episodic memory encoding and consolidation.

Aged↗
PubMed2006

Enhancing the informed consent process: a conceptual overview.

Concern about limitations in the ability to give valid informed consent among certain groups of individuals has led to increased interest in defining, measuring, and enhancing consent-related decision-making. In this overview, we summarize issues related to the definition of decision-making capacity, discuss methods that have been used to assess decision-making abilities and other aspects of informed consent, and briefly describe studies that aim to understand variation in different elements of informed consent. We then review strategies that have been used with the intent of improving aspects of the informed consent process. Finally, we provide an outline of areas that are in need of future studies in order to reach the ultimate goal of preserving as much autonomy as possible in at-risk populations, while still achieving valuable research and treatment goals.

Bioethics↗
PubMed2005

Review of longitudinal functional neuroimaging studies of drug treatments in patients with schizophrenia.

We systematically reviewed twenty-one functional neuroimaging studies that used longitudinal designs to investigate the effects of medication treatments on brain functioning among patients with schizophrenia. The studies reviewed were comprised of functional magnetic resonance imaging and positron emission tomography research using a baseline and at least one follow-up. The present review summarizes the different effects of medication and disease status on brain function, with attention to functional normalization, specific drug effects, and comparisons of typical versus atypical antipsychotics. Particular emphasis is given to methodological limitations in the existing literature, including lack of reliability data, clinical heterogeneity among studies, and inadequate study designs and statistics. Suggestions are made for improving future longitudinal neuroimaging studies of treatment effects in schizophrenia.

Antipsychotic Agents↗
PubMed2005

A preliminary study of interactive questioning methods to assess and improve understanding of informed consent among patients with schizophrenia.

Growing recognition of the inadequacy of traditional methods of providing informed consent, especially for individuals vulnerable to impaired decisional capacity, has spurred recent interest in how to assess and improve components of consent-related decision making. In this preliminary study, we aimed to compare different methods of interactive questioning during presentation of research consent information among patients with schizophrenia. Patients were randomized to receive either standard administration (SA) of a consent form or one of two interactive questioning methods: Corrective Feedback (CF), in which the correct answer was provided following the participant's response, or Errorless Learning (EL), in which correct answers were provided just prior to the question. The MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR) was used to measure understanding, appreciation, reasoning, and expression of a choice following presentation of the consent form. There was no significant effect of condition (SA vs. EL vs. CF) on any of the components of decisional capacity. Understanding scores measured during the consent process were higher than those measured afterward, but the two scores were highly correlated. Thus, the results of this randomized study suggest that interactive questioning neither helped nor harmed understanding, appreciation, or reasoning among patients with schizophrenia. Other considerations, however, may favor use of such methods in the consenting process.

Adult↗
PubMed2005

fMRI evidence of compensatory mechanisms in older adults at genetic risk for Alzheimer disease.

OBJECTIVE: To determine whether APOE genotype influences brain response and whether nonverbal stimuli generate findings comparable with those of previous studies that used verbal stimuli. The relationship between APOE genotype and blood oxygenation level dependent (BOLD) brain response was examined during a picture-encoding task in nondemented older adults. METHODS: Twenty nondemented participants with normal episodic memory function were divided into two groups based on the presence (n = 10) or absence (n = 10) of the APOE epsilon4 allele. Picture learning was completed during functional MRI in a blocked design alternating between experimental (novel pictures) and control (repeated picture) conditions. RESULTS: Nondemented older adults with an APOE epsilon4 allele showed greater magnitude and extent of BOLD brain response during learning of new pictures relative to their matched epsilon3 counterparts. Different patterns and directions of association between hippocampal activity and learning and memory performance were also demonstrated. CONCLUSIONS: The results suggest that brain response differences are not due to poorer general memory abilities, differential atrophy, or brain response during control conditions, but instead appear to be directly influenced by APOE genotype. Results are consistent with a compensatory hypothesis wherein older adults at genetic risk for Alzheimer disease by virtue of the APOE epsilon4 allele appear to require additional cognitive effort to achieve comparable performance levels on tests of episodic memory encoding.

Adaptation, Psychological↗
PubMed2005

Identification of Alzheimer disease risk by functional magnetic resonance imaging.

BACKGROUND: Functional magnetic resonance imaging plays a promising role in the preclinical characterization of Alzheimer disease (AD) for use in early diagnosis and in preventive drug trials. OBJECTIVE: To determine whether functional magnetic resonance imaging can reliably distinguish risk groups for AD among cognitively normal middle-aged adults. DESIGN: Cross-sectional case-control study. SETTING: University of California, San Diego, Alzheimer Disease Research Center participants and San Diego community volunteers. PARTICIPANTS: Twenty cognitively normal individuals (10 high risk and 10 low risk), aged 58 to 65 years, were divided into 2 groups based on the presence or absence of the apolipoprotein E epsilon4 allele and a positive family history of AD. MAIN OUTCOME MEASURES: Word pairs were presented in a blocked design alternating between conditions of novel pairs, repeated pairs, and fixation. Whole-brain differences in blood oxygenation level-dependent brain responses between conditions were compared across risk groups. RESULTS: Compared with the low-risk group, the high-risk group showed many areas of differential blood oxygenation level-dependent response in regions commonly associated with AD pathology (eg, the left medial temporal lobe). Furthermore, different patterns of association between left medial temporal lobe activity and memory performance were demonstrated. CONCLUSIONS: Results support a theory of up-regulation in neuronal memory systems in people at risk for AD many years before the typical age at disease onset. They further demonstrate that functional magnetic resonance imaging is a viable technique to identify persons at risk for AD.

Aged↗
PubMed2004

Abnormal brain response of chronic schizophrenia patients despite normal performance during a visual vigilance task.

Deficits of attention are common among individuals with schizophrenia (SZ) and are related both to genetic liability to the disorder and to functional outcome among patients. To explore the brain systems underlying these attentional abnormalities, we compared the response of nine patients with chronic SZ or schizoaffective disorder to that of 10 matched healthy individuals performing a simple visual vigilance task during functional magnetic resonance imaging. The two groups performed equivalently on the task. When the blood oxygen level dependent (BOLD) signal during identification of a target letter among similar-looking letters was compared to the response during fixation trials, both groups showed multiple clusters of significant brain response in widespread cortical regions. Compared with healthy participants, SZ patients showed a diminished response in the inferior frontal cortex and an abnormally enhanced response in right postcentral gyrus, right medial temporal lobe and left cerebellum. The results suggest that abnormalities of functional brain response to attentional tasks can be observed among patients with SZ even when behavioral performance is unimpaired, and provide further evidence that brain systems related to attention are likely to be involved in the pathophysiology of the disorder.

Adult↗
PubMed2004

A functional magnetic resonance imaging study of cortical asymmetry in bipolar disorder.

OBJECTIVES: Individuals with bipolar disorder (BPD) exhibit motor, perceptual, and cognitive disturbances involving predominantly right hemisphere dysfunction. This asymmetry has been used to advance the hypothesis that the pathogenesis of bipolar disorder may be related to disturbances of the right cerebral hemisphere. We employed functional magnetic resonance imaging to examine hemispheric asymmetries in manic and depressed BPD. A secondary goal of the study was to examine effects of psychotropic medications on blood volume changes in the motor cortices. METHODS: We studied 18 right-handed BPD and 13 right-handed normal healthy comparison subjects. Blood oxygen level dependent (BOLD) responses in the primary motor area (M1) and supplementary motor area (SMA) of both hemispheres were elicited during reaction time (RT) tasks. RESULTS: Healthy subjects activated the SMA in a reciprocal fashion with significantly greater activity in the left SMA for right hand trials and the right SMA for left hand trials. Depressed BPD subjects failed to show this normal reciprocity indicating a failure to suppress unwanted activity in the ipsilateral right SMA, whereas manic BPD subjects failed to suppress unwanted ipsilateral SMA activity in both hemispheres. Manic and depressed BPD subjects exhibited greater activity in the left primary motor area suggesting increased cortical excitability. BPD subjects treated with antipsychotics or mood-stabilizing medications exhibited longer RTs, lower BOLD responses in M1 and SMA, and a loss of normal hemispheric asymmetry in the SMA than untreated subjects. CONCLUSIONS: The presence of a right hemisphere disturbance in BPD is consistent with the hypothesis that the right hemisphere may be dominant in mood regulation. The presence of both left and right hemisphere disturbances in mania may explain the coexisting psychotic and affective symptoms observed in this condition.

Adult↗