Biomedical subjects

Brian V Shenal

Publications and source records attributed to Brian V Shenal.

9 recordsLinked to original sources

PubMed2006

Testosterone therapy in men with Parkinson disease: results of the TEST-PD Study.

BACKGROUND: Testosterone deficiency has been reported in patients with Parkinson disease (PD), Alzheimer disease, and Huntington disease. It is not known whether testosterone therapy (TT) in men with borderline hypogonadism and neurodegenerative diseases will be of substantial benefit. Previously, we reported that testosterone deficiency is more common in patients with PD compared with age-matched control subjects, and we also reported in 2 small open-label studies that some nonmotor symptoms responded favorably to TT. OBJECTIVE: To define the effects of TT on nonmotor and motor symptoms in men with PD and probable testosterone deficiency. DESIGN: Double-masked, placebo-controlled, parallel-group, single-center trial. PATIENTS: Two experimental groups: patients with PD who were receiving either TT or placebo. INTERVENTIONS: Participants received either the study drug by intramuscular injection (200 mg/mL of testosterone enanthate every 2 weeks for 8 weeks) or placebo (isotonic sodium chloride solution injections). In patients in each group, the testosterone serum concentration was obtained at each study visit. During 2 study visits, testosterone levels were blindly evaluated and the intramuscular testosterone dose was increased by 200 mg/mL if the free testosterone value failed to double from the baseline value. MAIN OUTCOME MEASURES: The primary outcome variable was the St Louis Testosterone Deficiency Questionnaire, and secondary outcome measures included measures of mood, cognition, fatigue, motor function, and frequency of adverse events. At the end of the double-blind phase, all patients were offered open-label TT and were followed up after 3 and 6 months. RESULTS: Fifteen patients in the placebo group (mean age, 69.9 years), receiving a mean total levodopa equivalent dose of 924 mg/d, had a baseline free testosterone level of 47.91 pg/mL, compared with 15 patients in the TT group (mean age, 66.7 years), receiving an average total levodopa equivalent dose of 734 mg/d, who had a baseline free testosterone level of 63.49 pg/mL. Testosterone was generally well tolerated. More subjects in the TT group experienced lower extremity edema (40% vs 20%). In 2 patients, 1 in each group, prostate-specific antigen levels were elevated from baseline. The improvement in the TT group compared with the placebo group (1.7 vs 1.1) on the St Louis Testosterone Deficiency Scale was not statistically significant. In addition, there were no significant differences in motor and nonmotor features of PD between the 2 groups, although a few subscales showed improvements (Hopkins Verbal Learning Test, P<.04; and Backward Visual Span subtrial, P<.03). However, long-term open-label TT resulted in delayed but sustained improvement in subjects in the TT group who continued to receive treatment (n = 6) compared with subjects in the placebo group who elected not to receive TT (n = 3). CONCLUSIONS: Testosterone therapy was generally well tolerated in elderly men with PD and probable testosterone deficiency. While there was no significant difference in the motor and nonmotor scales between the TT and placebo groups at the end of 8 weeks compared with baseline, this may be due to several study limitations, including small sample size, a strong placebo effect with intramuscular therapy, and short follow-up that did not allow measurement of delayed effects of TT in some subjects. Until more definitive studies are reported, practitioners should be particularly cautious in treatment of low testosterone concentrations in men with PD and borderline testosterone deficiency, and careful consideration should be given to the risks vs the benefits of TT.

Affect↗

PubMed2006

Finger agnosia in Alzheimer disease.

BACKGROUND AND OBJECTIVE: The purpose of this study was to learn if a deficit of finger naming (finger agnosia or anomia) is a sensitive test for Alzheimer disease (AD) and the best means of testing for finger agnosia. METHODS: The subjects were 38 patients with AD and 10 matched normal controls. All subjects were asked to name the thumb, index, and pinky fingers. RESULTS: No control subject had trouble naming any of these fingers, but 37% of the AD subjects did. When AD patients had difficulty with finger naming, they always had trouble naming the index finger. CONCLUSIONS: In the absence of stroke, the inability to name the index finger seems as an indicator of dementia. Although brief, this test is not extremely sensitive test for AD.

Agnosia↗

PubMed2004

Hostility and facial affect recognition: effects of a cold pressor stressor on accuracy and cardiovascular reactivity.

The effects of hostility and a cold pressor stressor on the accuracy of facial affect perception were examined in the present experiment. A mechanism whereby physiological arousal level is mediated by systems which also mediate accuracy of an individual's interpretation of affective cues is described. Right-handed participants were classified as high hostile (N = 28) or low hostile (N = 28) using the Cook Medley Hostility Scale. The high-hostile group met joint selection criteria. Only high-hostile participants who showed cardiovascular reactivity to the cold pressor, with systolic BP change exceeding the group mean were included. Groups were further subdivided into cold pressor and non-cold pressor test conditions. It was predicted that high-hostile men, relative to low-hostile men, would show decreased perceptual accuracy when presented with happy, angry, and neutral facial configurations within the left visual field (LVF). Results indicated that high-hostile men were less accurate than low-hostile men in the LVF. Further, pre-stress accuracy scores in the high-hostile men were similar to the post-stress accuracy scores of the low-hostile men. The lateralization of affective function and the role of physiological arousal in affective facial perception are discussed.

Affect↗

PubMed2004

Dynamic lateralization: hostility, cardiovascular regulation, and tachistoscopic recognition.

This experiment tested a hypothesis linking the right cerebral regulation of hostility and cardiovascular arousal. It also replicates related research regarding hostility, cardiovascular regulation, and auditory recognition (Shenal Harrison, 2003) through the visual modality. Thirty low- and high-hostile participants (n = 30) were identified using the Cook Medley Hostility Scale (CMHS). Only right-handed male participants with no significant medical or psychological history completed the experiment. All participants completed the cold pressor paradigm. Cardiovascular measures (systolic blood pressure [SBP] and diastolic blood pressure [DBP]) were recorded and tachistoscopic lexical recognition procedures were administered before and after the physical stressor. The primary finding of this research was greater left cerebral activation (decreased cardiovascular reactivity) following the tachistoscopic lexical recognition tasks and greater right cerebral activation following the painful (cold pressor) stressor.

Analysis of Variance↗

PubMed2004

Primacy and recency effects found using affective word lists.

This experiment tested hypotheses linking the right cerebral regulation of hostility and affective verbal learning. First, patterns of recall for positive, negative, and neutral affective list learning among high- and low-hostile individuals were examined. It was expected that low-hostiles would recall more items from the positive list and that high-hostiles would recall more words from the negative affective list. Also, independent of groups, it was expected that there would be a primacy effect for negative words and a recency effect for positive words. Exploratory analyses examined the relation between hostility and primacy and recency effects on the positive and negative word lists. High- and low-hostile participants (n = 65) completed the positive list learning task, the negative list learning task, or the neutral list learning task. Data analyses revealed no significant difference between the high- and low-hostile groups on the different affective lists. However, results of the present investigation reliably demonstrated the predicted primacy and recency effects. There was a primacy effect for the negative affective list and a recency effect for the positive affective list. These findings are consistent with previous research investigating the acquisition pattern of affective verbal learning.

Adult↗

PubMed2003

The neuropsychology of depression: a literature review and preliminary model.

Neuropsychological research provides a useful framework to study emotional problems, such as depression, and their correlates. This paper reviews several prominent neuropsychological theories. Functional neuroanatomical systems of emotion and depression are reviewed, including those that describe cerebral asymmetries in emotional processing. Following the review, a model that is composed of three neuroanatomical divisions (left frontal, right frontal, and right posterior) and corresponding neuropsychological emotional sequelae within each quadrant is presented. It is proposed that dysfunction in any of these quadrants could lead to symptomatology consistent with a diagnosis of depression. The proposed model combines theories of arousal, lateralization, and functional cerebral space and lends itself to scientific methods of investigation. Accordingly, research, prevention, and treatment programs in accordance with the proposed model may promote an improved understanding of the neuropsychological mechanisms involved in depression.

Brain↗

PubMed2003

Investigation of the laterality of hostility, cardiovascular regulation, and auditory recognition.

This experiment tested a hypothesis linking the right cerebral regulation of hostility and cardiovascular arousal. First, replication of previous research supporting heightened cardiovascular (systolic blood pressure [SBP] and diastolic blood pressure [DBP]) reactivity among high hostile participants was partially successful. Second, dynamic variations in functional cerebral asymmetry in response to emotional linguistic processing was measured. Thirty low- and high-hostile, undergraduate volunteer participants (n = 30) were identified using the Cook Medley Hostility Scale (CMHS). Only healthy, right-handed male participants completed the experiment. All participants completed the negative affective auditory verbal learning test (AAVLT). Cardiovascular measures (SBP and DBP) were recorded and dichotic listening procedures were administered before and after the cognitive affective stressor. The results support greater left cerebral activation among both groups following the dichotic phoneme listening tasks and greater right cerebral activation among both groups following an emotional linguistic (affective verbal learning) cognitive stressor.

Affect↗

PubMed2003

Quantitative EEG diagnostic confirmation of expressive aprosodia.

Quantitative electroencephalography (QEEG) was used to confirm predictions emanating from the neuropsychological examination of an adolescent with expressive aprosodia. Previous research has indicated that expressive deficits in prosody can be caused by cerebral damage to the right hemisphere region homologous to Broca's area. The neuropsychological evaluation of this individual indicates probable right anterior cerebral dysfunction. Taken together, a priori hypotheses included a relative deficit in cerebral arousal of right-relative to left-frontotemporal regions. EEG results confirm the hypothesis and provide case study evidence for both: (a). right anterior mediation of prosodic expression as well as (b). support for the inclusion of QEEG as part of a clinical neuropsychological evaluation.

Adolescent↗

PubMed2002

Grip-strength, fatigue, and motor perseveration in anxious men without depression.

OBJECTIVE: To investigate the influence of anxiety without depression on functional motor asymmetry in adult men. Thus, left-and right-hand grip strength, fatigue across trials, and motor perseveration was examined among 60 right-handed men, half of whom had been classified as anxious without depression (HI, n = 30) and the other half as nonanxious without depression (LO, n = 30). BACKGROUND: There is substantial empirical support for the notion that individuals with negative affect experience relative right anterior activity. Moreover, previous studies using other groups of interest (e.g., depression and hostility) have found evidence of functional motor asymmetry that is supportive of relative right anterior activation during negative affect. Less is known about functional motor asymmetry among individuals that report anxiety without depression. METHOD: To obtain indices of perseveration, strength, and fatigue, HI and LO anxious subjects were asked to successively squeeze a hand dynamometer. Dependent measures (in kg) were derived from performance with the left and right hands across trials. RESULTS: In contrast to LO anxious subjects, HI anxious subjects did not demonstrate right-hand superiority for grip-strength. Moreover, significant positive correlations existed between grip strength and trait anxiety scores for LO anxious subjects, but not for HI anxious subjects. CONCLUSIONS: The data are partially supportive of differences in functional motor asymmetry between HI and LO anxious individuals. The findings are interpreted as supportive of relative right anterior activity (and possibly decreased left anterior activity) among individuals that report elevated levels of anxiety. Implications for relative right-hemisphere activity and decreased left anterior activity are discussed, and alternative explanations are introduced.

Adult↗