Biomedical subjects

Margaret Primeau

Publications and source records attributed to Margaret Primeau.

5 recordsLinked to original sources

PubMed2006

Functional magnetic resonance imaging response to increased verbal working memory demands among patients with multiple sclerosis.

Multiple sclerosis (MS) patients frequently experience impaired verbal working memory (VWM). Functional magnetic resonance imaging (fMRI) may help identify neural mechanisms underlying these deficits. Neuroimaging studies of healthy adults have characterized responses associated with increased VWM demands during the n-Back task, suggesting that this experimental paradigm could help identify neural correlates of VWM deficits among MS patients. Fifteen MS patients and 15 matched control participants completed the n-Back during whole-brain fMRI. Mean signal during adjacent 0-Back blocks was subtracted, on a voxel-wise basis, from mean signal observed during n-Back blocks. Resulting difference scores for 1-, 2-, and 3-Back were compared across groups and difficulty levels. Signal intensity was positively related to difficulty level in anterior regions, including premotor, supplementary motor, and dorsolateral prefrontal cortices. MS patients exhibited significantly greater intensity in these areas compared to controls during the 1-Back, while portions of the left superior frontal gyrus, cingulate, and parahippocampal gyri were relatively less intense at more difficult levels. MS group responses were slower during the 1-Back and tended to be slower during the 3-Back; however, accuracy did not differ at any level. Lesion load was positively related to only 1-Back activity and unrelated to any performance measure. Results suggest that compensatory activity occurs among MS patients matched on performance accuracy. Furthermore, compensatory activity occurs predominantly in regions associated with VWM, and this may decline relative to controls as task demands increase. These findings may help to explain why MS patient performance decreases as a function of effort on neuropsychological tests.

Brain↗

PubMed2005

Neurorehabilitation of behavioral disorders following lightning and electrical trauma.

Neurobehavioral problems after lightning and electrical injuries are diverse. Commonly reported are decreased cognitive function, pain syndromes, depression, posttraumatic stress disorder, and significant alterations in social and work roles. While the problems resemble those following other kinds of accidents, the injury scenarios for lightning and electrical trauma are unique, and seem to invite more skepticism and controversy in medical and legal realms when the survivors seek help. Studies of lightning and electrical injuries have identified disabling neuropsychiatric changes for some survivors, often persistent and occasionally progressive, that appear weakly related to litigation status, inconsistently related to injury scenarios, and likely influenced by individual premorbid emotional and coping patterns. Standards of care in the fields of brain injury, behavioral medicine, and psychotherapy can inform rehabilitation strategies. Proper assessment is important, as well as an individualized approach to treatment. Multidisciplinary intervention focuses on managing symptoms, learning compensatory skills, providing psychosocial support, and preventing maladaptive behaviors. It has been therapeutic for some patients to become activists for better awareness and prevention.

Adaptation, Psychological↗

PubMed2004

Quantitative electroencephalography in frontotemporal dementia with methylphenidate response: a case study.

Frontotemporal dementia is an underdiagnosed illness with predominant behavioral and executive manifestations. Historically, diagnosis has been based on a combination of clinical history, neuropsychological testing, and brain imaging. No effective treatment currently exists for this disorder. A case is presented using quantitative EEG with methylphenidate challenge correlated with SPECT. The patient underwent neuropsychological testing, a SPECT brain study, and a quantitative EEG, which was repeated after methylphenidate administration. SPECT was significant for hypoperfusion to the bilateral frontotemporal regions, with left-sided hypoperfusion greater than homologous right as demonstrated by LORETA analysis. QEEG correlated with SPECT, and demonstrated profound left greater than right bi-frontotemporal slowing, which normalized partially after methylphenidate administration. The patient has remained on methylphenidate as an outpatient, and has had significant behavioral improvement. Quantitative EEG may provide both diagnostic and therapeutic data with regard to frontotemporal dementia. Further studies of methylphenidate in this population are needed to confirm these data.

Aged↗

PubMed2004

Functional magnetic resonance imaging of working memory among multiple sclerosis patients.

BACKGROUND AND PURPOSE: Verbal working memory (VWM) deficits have been a well-replicated finding among patients with multiple sclerosis (MS). Functional magnetic resonance imaging (FMRI) studies have described a VWM system in healthy samples; however, functional neuroimaging of this system among MS patients is just beginning to appear. METHODS: Fifteen MS patients and 15 sex-, age-, education-, and IQ-matched healthy control (HC) participants completed a 2-Back VWM task as whole-brain FMRI was conducted. RESULTS: Each group exhibited increased brain activity compared to the O-Back control task in regions associated with the 2-Back in previous neuroimaging studies. These included Broca's area, supplementary motor area (SMA), premotor cortices (PMC), and dorsolateral prefrontal cortices (DLPFC). MS patients exhibited greater cortical activity than did HC participants in left primary motor and somatosensory cortices, PMC, DLPFC, anterior cingulate, and bilateral SMA. MS patients exhibited relatively less activation in Broca's area, bilateral cerebellum, and other regions not typically associated with the 2-Back (e.g., right fusiform gyrus, left lingual gyrus, right hippocampus). Performance accuracy and reaction time did not differ between groups. CONCLUSIONS: Normal performance of a challenging VWM task among high-functioning MS patients is associated with a shift toward greater activity in regions related to sensorimotor functions and anterior attentional/executive components of the VWM system. Posterior memory storage systems appeared unaffected, while portions of the visual processing and subvocal rehearsal systems were less active. Although a shift in neural activity was noted relative to HC participants, deviation from regions normally involved in VWM function was not observed in this patient sample.

Adult↗

PubMedDate not supplied

Androgens and mood dysfunction in women: comparison of women with polycystic ovarian syndrome to healthy controls.

OBJECTIVE: Our understanding of the organizational and activational effects of human gonadal hormones on behavior has depended on the study of endocrine disorders. Polycystic ovarian syndrome (PCOS) is a hormonal disorder that begins in puberty and is characterized by chronically augmented free testosterone (FT) levels. The purposes of this study were 1) to compare negative mood states of women with PCOS to those of women with normal hormonal levels and 2) to examine the relationship between negative moods and androgens. METHODS: Twenty-seven women with PCOS were case-matched to 27 normal menstruating women on body mass index since being overweight is a common symptom of PCOS and could affect mood states. Serum levels of FT, total testosterone, sex hormone binding globulin, estradiol, and progesterone were determined. Self-reported depression, anger, anxiety, and aggression were analyzed between groups, and individual scores were compared across groups to hormone values. RESULTS: Depression was significantly increased in the PCOS group and remained so after considering the variance related to physical symptomatology and other mood states. Furthermore, a curvilinear relationship between FT and negative affect across groups was suggested: the most elevated negative mood-scale scores were associated with FT values just beyond the upper limits of normal, while lower negative mood levels corresponded to both normal and extremely high values of FT. CONCLUSIONS: These results are consistent with a model of activational influences of testosterone on adult female behavior. Implications are discussed for future research and for treatment of PCOS and other menstrual-cycle mood disorders.

Adolescent↗