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Biomedical subjects

Paula K Shear

Publications and source records attributed to Paula K Shear.

At least 19 recordsLinked to original sources
PubMed2006

Anxiety, depression, and behavioral symptoms of executive dysfunction in ecstasy users: contributions of polydrug use.

BACKGROUND: Given ecstasy's (MDMA) potential serotonergic neurotoxicity, it is plausible that regular ecstasy users would have an elevated prevalence of behavioral executive dysfunction or mood symptoms. However, recent studies have found that the relationship between ecstasy use and psychological symptoms was no longer significant after controlling for marijuana use (e.g., Morgan et al., 2002). The goal of the present study was to examine the relationship between ecstasy exposure and self-reported executive functioning and psychological symptoms after controlling for gender, ethnicity, and other drug use. METHODS: Data were collected from 65 men and women with a wide range of ecstasy use (including 17 marijuana-using controls). Participants were administered the Frontal Systems Behavioral Scale, State-Trait Anxiety Inventory for adults, and the Beck Depression Inventory-2nd edition. RESULTS: Although 19-63% of the ecstasy users demonstrated clinically elevated psychological symptoms, frequency of ecstasy use did not predict the psychological symptoms. No gender differences or interactions were observed. CONCLUSIONS: These results revealed that, although ecstasy users demonstrate elevated levels of psychological symptoms and executive dysfunction, these symptoms are not statistically associated with their ecstasy consumption. Instead, other drug use (alcohol, marijuana, opioids, and inhalants) significantly predict psychological symptoms in this sample of polydrug users.

Affect↗
PubMed2006

Memory functioning in polysubstance dependent women.

BACKGROUND: The vast majority of studies on polysubstance abuse or dependence have utilized male participants; therefore, the specific neuropsychological effects of polysubstance dependence in women are relatively unknown. The goal of the present study is to examine the effects of polysubstance dependence on women's verbal and visual memory ability. METHODS: Data were collected from 109 women (46 controls and 63 polysubstance dependence women who were similar in ethnic identification, education, age, and verbal ability). A series of multiple regressions were run to test whether group membership significantly predicted performance on the Benton Visual Retention Test and the California Verbal Learning Test after controlling for important demographic characteristics. RESULTS: The primary results indicated that the polysubstance dependent women had significantly poorer verbal learning ability (ranging from p<.005 to .05) than the control group, while no differences were found in visual memory ability. Further, significant bivariate relationships were observed between frequency of alcohol and cocaine use and verbal learning, delayed recall, and recognition ability. CONCLUSIONS: The results confirm that polysubstance dependence is associated with deficient encoding of verbal information. In addition, past year frequent use of alcohol and cocaine was associated with more severe deficits in delayed recall and recognition ability among polysubstance dependent women at the bivariate level.

Adult↗
PubMed2006

Stability of estimated IQ across mood state in patients with bipolar disorder.

OBJECTIVES: The goal of this study was to assess the impact of mania symptoms on the stability of the American version of the National Adult Reading Test (ANART), a measure that provides a putative estimate of premorbid intellectual functioning. METHODS: The ANART was administered to a sample of 10 inpatients with bipolar disorder who were experiencing an acute episode of mania. During a subsequent follow-up visit during which these individuals exhibited at most minimal mood symptoms, the ANART was re-administered. RESULTS: ANART estimated intelligence quotient (IQ) scores during mania and affective stability were assessed in the 10 patients using a paired sample t-test. Within-subject performance across the two mood states did not significantly differ [t(9) = -1.24, p = 0.25]. Additionally, the greatest individual difference across mood states was only 3.68 points, and the average estimated IQ difference across mood states was 1.66. CONCLUSIONS: While the results are preliminary and based on a small sample, the highly consistent scores achieved across mood states in this study suggest that the ANART is a reliable indicator of premorbid IQ.

Acute Disease↗
PubMed2006

Anterior cingulate subregion volumes and executive function in bipolar disorder.

OBJECTIVE: Although research findings suggest a relationship between the function of anterior cingulate cortex (ACC) and both cognitive ability and the pathophysiology of bipolar disorder (BPD), few studies have examined cognitive correlates of specific ACC subregion volumes in BPD. Therefore, the primary aim of this study was to examine the relationship between magnetic resonance imaging (MRI)-derived gray and white matter volumes of ACC subregions (caudal, rostral, and subgenual) and performance on tests of executive function in 27 patients with BPD and 22 healthy subjects. METHODS: 1.5T MRI and neuropsychological assessment were conducted with all participants. RESULTS: MANCOVA revealed statistically significant group differences in performance on executive function measures. However, no group differences were observed in any of the ACC white matter or gray matter regions of interest. Multiple regression analyses revealed that rostral and subgenual gray matter each interacted significantly with group in predicting performance on the Wisconsin Card Sorting Test. In addition, a significant interaction was observed between group and both rostral gray and white matter in predicting performance on the Trail Making Test. CONCLUSIONS: The results of this preliminary study support the extant literature that suggests that patients with BPD perform more poorly than healthy subjects on tests of executive function. Furthermore, the relationship between ACC subregion volumes and cognitive test performance was found to differ between patients with BPD and healthy subjects, despite comparable ACC volumes in the two groups.

Adolescent↗
PubMed2005

Deterministic center of pressure patterns characterize postural instability in Parkinson's disease.

Static posturographic recordings were obtained from six Parkinson's patients and six age-matched, healthy control participants. The availability of vision and visuo-spatial cognitive load were manipulated. Postural sway patterns were analyzed using recurrence quantification analysis (RQA), which revealed differences in center of pressure (COP) dynamics between Parkinson's and control participants. AP COP trajectories for the Parkinson's group were not only significantly more variable than for the control group, but also exhibited distinct patterns of temporal dynamics. The visual manipulation did not differentially affect the two groups. No cognitive load effects were found. The results are generally consistent with the hypothesis that pathological physiological systems exhibit a tendency for less flexible, more deterministic dynamic patterns.

Adult↗
PubMed2005

Processing efficiency and sustained attention in bipolar disorder.

We hypothesized that patterns of sustained attention performance in bipolar disorder were consistent with processing efficiency theory--a theory of the relationship between central processing capacity and performance. We predicted (1) sustained attention deficits during mania because symptoms interfere with limited-capacity executive control processes resulting in decreased performance effectiveness; and (2) decreased processing efficiency during euthymia, as indicated by speed/accuracy tradeoffs, consistent with a stable phenotypic abnormality. Twenty-five manic bipolar, 23 euthymic bipolar, and 28 healthy comparison participants were compared on a continuous performance task and administered symptom-rating scales. The manic group was significantly impaired on overall perceptual sensitivity and demonstrated a significant linear decrease in performance over time, consistent with impaired sustained attention. The euthymic group evidenced significantly slower overall hit reaction time (RT), but when RT was controlled they performed similarly to the healthy group over time. Two discriminant functions combined to separate the groups on manic symptom severity and on-task effort/strategy use. These findings are consistent with processing efficiency theory. They suggest that euthymic patients sustain attention through effortful control at the expense of processing efficiency, while acute mania reduces the capacity for control and impairs sustained attention. Problems with processing efficiency are viewed as trait characteristics of bipolar disorder that may be overlooked by traditional error-based assessments.

Adult↗
PubMed2005

Working memory and inhibitory control among manic and euthymic patients with bipolar disorder.

Bipolar disorder (BPD) is a severe psychiatric illness that is characterized by episodes of extreme mood states. The affective components of bipolar disorder have been studied extensively, but only recently have investigators begun to systematically examine its cognitive concomitants. Although executive dysfunction has been reported in this population, especially while patients are manic, the tasks administered in many previous studies have made it difficult to determine the specific executive abilities that were compromised. The present study examined 15 patients with bipolar disorder who were manic, 18 who were euthymic, and 18 healthy participants. Tests were selected to evaluate two specific aspects of executive functioning in these participants. The Object Alternation Task was given as a measure of inhibitory control, and the Delayed Response Task was included as a measure of spatial delayed working memory. All groups performed similarly on the Delayed Response Task. On the Object Alternation Task, however, the manic and euthymic patients committed significantly more perseverative errors than healthy participants. These results indicated that patients in the present sample had relatively normal working memory abilities, but had a deficit in behavioral self-regulation, which was evident across mood states.

Adolescent↗
PubMed2005

Ecstasy (MDMA) exposure and neuropsychological functioning: a polydrug perspective.

Ecstasy (MDMA) is a popular drug that can act as a selective serotonin neurotoxin in several species. The goal of the present study was to examine the relationship between ecstasy exposure and cognitive functioning after controlling for other drug use and demographic variables. Furthermore, we assessed whether gender was a moderator of the relationship between cognitive functioning and ecstasy use. Data were collected from 31 men and 34 women with a wide range of ecstasy use (17 marijuana users with no ecstasy use and 48 ecstasy users ranging from low to heavy use). Participants were interviewed and administered a battery of neuropsychological tests. The primary finding was that ecstasy exposure was significantly related to poorer verbal learning and memory ability in a dose-dependent manner, while no such relationship was observed between ecstasy exposure and executive functioning or attentional ability. Gender was found to significantly moderate the relationship between ecstasy consumption and design fluency. These results suggest primary memory dysfunction among abstinent recreational ecstasy users. This finding is consistent with reports of hippocampal vulnerability, particularly among heavy users.

Adolescent↗
PubMed2005

Processing efficiency and directed forgetting in bipolar disorder.

We hypothesized that patients with bipolar disorder would demonstrate verbal recognition performance deficits consistent with processing efficiency theory, a theory about how emotional states modulate performance by interfering with working memory resources or increasing cognitive arousal/effort. We predicted that (1) a manic group (n=26) would demonstrate slow reaction time (RT) and low accuracy, (2) a euthymic group (n=23) would demonstrate slow RT to maintain high accuracy; and (3) a healthy comparison group (n=25) would demonstrate fast RT and high accuracy. The groups were administered symptom-rating scales and compared on a computerized, trial-by-trial, directed forgetting in recognition task. This task requires participants to comply with an overt instruction to forget irrelevant studied words, and it places a relatively high demand on working memory. The manic group was impaired on directed-forgetting sensitivity; however, when RT was statistically controlled, the groups demonstrated similar directed-forgetting effects. These findings are consistent with processing efficiency theory. They suggest that bipolar patients perform directed forgetting in recognition by increasing effortful control at encoding at the expense of processing efficiency, although acute mania reduces the capacity for control, thereby impairing recognition performance. Problems with processing efficiency are viewed as trait characteristics of bipolar disorder that may be overlooked by traditional error-based assessments.

Adult↗
PubMed2004

Parametric neurocognitive task design: a pilot study of sustained attention in adolescents with bipolar disorder.

BACKGROUND: Disruption in attention is one of the core features of bipolar disorder (BP). Therefore, neurocognitive paradigms assessing brain function in response to tasks of increasing attentional difficulty may be useful to clarify the neurophysiology of bipolar disorder. The aim of this study was to obtain pilot performance data using a parametric task of sustained attention that might be useful as an experimental paradigm for future functional neuroimaging studies. We hypothesized that task performance would worsen as task difficulty increased in manic and euthymic bipolar and healthy subjects. Additionally, we hypothesized that the groups would exhibit a similar decline in task performance as level of task difficulty increased and that within each level of task difficulty there would be similar performance among groups. METHODS: A novel parametric Continuous Performance Task-Identical Pairs (CPT-IP) version was administered to manic (N=10) and euthymic (N=10) adolescents with bipolar disorder and healthy controls (N=10). RESULTS: There were no statistically significant group differences in task performance as measured by discriminability, percent correct, false positive hits, and reaction time. However, within each group, performance on all measures worsened with increased attentional difficulty (p<0.0001). There were no statistically significant task difficulty by group interactions. Furthermore, medication exposure and comorbid attention-deficit hyperactivity disorder were not associated with most measures of task performance. However, BP subjects who were treated with medications had slower task performance compared with BP subjects who were unmedicated. LIMITATIONS: Larger studies examining the effects of specific medication classes on task performance are necessary. CONCLUSIONS: The results of this pilot study suggest that manic and euthymic BP patients do not exhibit attentional dysfunction as compared to healthy adolescents using a novel parametric version of the CPT-IP. Furthermore, our parametric CPT-IP version may be useful as a novel parametric neurocognitive paradigm for future functional neuroimaging studies of bipolar adolescents.

Adolescent↗
PubMed2004

Cognitive functioning and length of abstinence in polysubstance dependent men.

To date, there are few large-scale studies that have examined the relationship between duration of abstinence and cognitive functioning in polysubstance-dependent individuals. Existing large-scale studies of polysubstance abusers have reported only minimal recovery of cognitive functioning with abstinence [Arch. Gen. Psychiatry 35 (1978) 1063]. The goal of this study is to test whether length of abstinence (1 day and 14 months) is related to cognitive ability in a large cross-sectional sample of men recovering from dependence on at least two drugs (N = 207). A series of Poisson and linear regressions were run to test whether length of abstinence is associated with neuropsychological performance while controlling for demographic variables, raw Vocabulary score, drug use, and dependency. The primary finding is that increasing length of abstinence was not statistically associated with superior neuropsychological ability. This suggests that the abuse of multiple substances potentially produces long-lasting neuropsychological impairment with minimal recovery of functioning over a 1-year period.

Adult↗
PubMed2003

Facial affect recognition deficits in bipolar disorder.

Patients diagnosed with bipolar disorder (BPD), by definition, have problems with emotional regulation. However, it remains uncertain whether these patients are also deficient at processing other people's emotions, particularly while manic. The present study examined the ability of 25 manic bipolar patients and 25 healthy participants on tasks of facial recognition and facial affect recognition at three different presentation durations: 500 ms, 750 ms, and 1000 ms. The groups did not differ in terms of age, education, sex, ethnicity, or estimated IQ. The groups did not differ significantly on either a novel computerized facial recognition task or the Benton Facial Recognition Test. In contrast, the bipolar group performed significantly more poorly than did the comparison group on a novel facial affect labeling task. Although the patient group had slower reaction times on all 3 computerized tasks, the presentation duration did not have an effect on performance in the patients. This study suggests that patients with bipolar disorder are able to recognize faces, but have difficulty processing facial affective cues.

Adolescent↗
PubMed2003

Verbal memory in mania: effects of clinical state and task requirements.

OBJECTIVES: Manic patients exhibit impaired verbal learning and memory, particularly following longstanding illness. However, it is unclear whether recognition and recall performance are differentially influenced by a manic mood state. METHODS: To examine this issue, we administered the California Verbal Learning Test and symptom-rating scales to inpatients with pure or mixed mania, euthymic outpatients, and healthy comparison subjects. RESULTS: An overall performance difference was identified between groups. Manic and euthymic patients performed more poorly than healthy subjects on recall. However, manic patients performed more poorly than euthymic patients and healthy subjects on recognition. CONCLUSIONS: These results suggest that verbal retrieval deficits are stable vulnerability indicators in bipolar disorder, whereas verbal encoding deficits are manic episode indicators. The known subcortical dysfunction in this disorder may produce stable retrieval deficits while acute mood symptoms attenuate encoding during affective episodes only.

Adult↗
PubMed2003

Detecting neuropsychological malingering: effects of coaching and information.

Concerns that patients presenting for neuropsychological assessment may not be putting forth maximum effort during testing has prompted the development of measures designed to detect malingering and incomplete effort. Two of these measures are the Computerized Assessment of Response Bias-97 (CARB-97) and Word Memory Test (WMT). Despite widespread use of these instruments, no study has been published determining the vulnerability of neuropsychological malingering measures to explicit coaching or brain injury information. The present study, using analog participants, found that the CARB-97 and WMT differentiate "normal" from "malingered" instructional sets, and show little difference between nai;ve and coached malingering efforts. There was also little difference between providing brain injury information and a no-information condition, but when effects were present, the information group generally scored worse. Further, it was found that response times (RTs), in addition to items correct, may also be effective in detecting those who are not giving their full effort.

Adolescent↗
PubMed2002

The relationship between cognitive dysfunction and coping abilities in schizophrenia.

Cognitive dysfunction is a core feature of schizophrenia [Psychiatr. Clin. North Am., 16 (1993) 295; Psychopharmacology: The fourth generation of progress, Raven Press, New York (1995) 1171; Clinical Neuropsychology, Oxford University Press, New York (1993) 449] and is related to psychosocial functioning in this population [Am. J. Psychiatry, 153 (1996) 321]. It is unclear whether cognitive dysfunction is related to specific areas of functioning in schizophrenia, such as coping abilities. Individuals with schizophrenia have deficient coping skills, which may contribute to their difficulties dealing with stressors [Am. J. Orthopsychiatry, 62 (1992) 117; J. Abnorm. Psychol., 82 (1986) 189]. The current study examined the relationship between coping abilities and cognitive dysfunction in a community sample of individuals with schizophrenia. It was hypothesized that executive dysfunction and mnemonic impairments would be positively related to deficiencies in active coping efforts involving problem solving and self-initiation (e.g. advocating for oneself and others with mental illness and becoming involved in meaningful activities, such as work), independent of the contributions of the general intellectual deficits associated with the disorder and psychiatric symptoms. The results indicated that both executive dysfunction and mnemonic impairments were related to decreased usage of active coping mechanisms after controlling for general intellectual deficits. Further, recognition memory made independent contributions to the prediction of coping involving action and help seeking after controlling for the effects of negative symptoms. These findings suggest that individuals with schizophrenia may be less flexible in their use of coping strategies, which may in turn contribute to their difficulties in coping with mental illness and its consequences.

Adaptation, Psychological↗
PubMed2002

Parental reports of executive dysfunction in adolescents with bipolar disorder.

Bipolar disorder (BPD) is a serious mental illness that affects children and adolescents at a rate similar to that seen in adults. Extremely little is known, however, about cognitive functioning in childhood and adolescent BPD. The present study represents an initial effort to examine executive functioning in adolescents with BPD who are in a manic or mixed mood state, by collecting data from caregivers about the participants' performance on everyday tasks thought to be mediated by executive functioning abilities, using the Behavior Rating Inventory of Executive Function. In comparison to healthy volunteers, adolescents with BPD exhibited significant elevations across all of the measured functional domains. These elevations were evident even in adolescents with BPD who did not have comorbid ADHD, although they were most prominent in those with comorbidity. The findings suggest that adolescents with BPD have functional deficits on tasks requiring executive functioning skills that are not explicable solely on the basis of comorbid ADHD.

Adolescent↗
PubMed2002

Academic and cognitive abilities in children of parents with bipolar disorder: a test of the nonverbal learning disability model.

It has been hypothesized that children who are at genetic risk to develop bipolar disorder demonstrate deficiencies consistent with the syndrome of nonverbal learning disabilities (NLD); however, this hypothesis has never been tested directly. In the present study, a group of at-risk children (AR group; N = 28) was compared to a demographically matched control group of children of healthy parents (HC group; N = 24) for evidence of a constellation of features associated with NLD. Some characteristic features of NLD were evident, including significant Verbal IQ (VIQ) > Performance IQ (PIQ) discrepancies and psychomotor deficits. However, academic deficiencies in mechanical arithmetic relative to reading and spelling abilities were not demonstrated. These findings replicate and extend the current literature on the cognitive functioning of children of parents with Bipolar disorder (BPD). The results, however, do not support the presence of NLD in these children.

Bipolar Disorder↗