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1.
Effects of dual-task interference on swallowing in healthy aging adults.
Krishnamurthy, R, Philip, R, Balasubramanium, RK, Rangarathnam, B
PloS one. 2021;(6):e0253550
Abstract
A wide body of literature has demonstrated that the neural representation of healthy swallowing is mostly bilateral, with one hemisphere dominant over the other. While several studies have demonstrated the presence of laterality for swallowing related functions among young adults, the data on older adults are still growing. The purpose of this paper is to investigate potential changes in hemispheric dominance in healthy aging adults for swallowing related tasks using a behavioral dual-task paradigm. A modified dual-task paradigm was designed to investigate the potential reduction in hemispherical specialization for swallowing function. Eighty healthy right-handed participants in the study were divided into two groups [Group 1: young adults (18-40 years) and Group 2: older adults (65 and above)]. All the participants performed a timed water swallow test at baseline and with two interference conditions (silent word repetition, and facial recognition). The results of the study revealed the following 1) a statistically significant effect of age on swallow performance; 2) statistically significant effect of each of the interference tasks on two of the swallow measures (VPS and VPT) in younger adults; and 3) no significant effect of the interference tasks on the swallowing performance of older adults. These findings suggest that aging substantially affects swallowing in older individuals, and this potentially accompanies a reduction in the hemispheric specialization for swallowing related tasks.
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2.
Somatic mutations in the KCNJ5 gene raise the lateralization index: implications for the diagnosis of primary aldosteronism by adrenal vein sampling.
Seccia, TM, Mantero, F, Letizia, C, Kuppusamy, M, Caroccia, B, Barisa, M, Cicala, MV, Miotto, D, Rossi, GP
The Journal of clinical endocrinology and metabolism. 2012;(12):E2307-13
Abstract
CONTEXT Somatic mutations in the selectivity filter of KCNJ5 K(+) channel were found to be associated with higher plasma aldosterone concentrations in the patients with an aldosterone-producing adenoma (APA). OBJECTIVE We investigated whether plasma aldosterone levels and the lateralization index are higher from the side with the APA with the mutation, as compared with those without the mutation. DESIGN From 170 consecutive APA patients with comprehensive clinical and KCNJ5 data and a conclusive diagnosis, we recruited 91 patients with adrenal vein sampling and follow-up data. We measured CYP11B1 and CYP11B2 mRNA in APA tissue and plasma aldosterone (PAC) and plasma cortisol concentrations (PCC) in adrenal vein blood. To determine whether KCNJ5 mutations affected aldosterone output from the APA, we calculated the lateralization index (defined as the ratio of PAC to PCC at the APA side over the PAC to PCC ratio at the contralateral side). We also calculated two indexes of the aldosterone production from the APA side and the contralateral suppression index. RESULTS The mRNA content of CYP11B2, but not of CYP11B1, and, accordingly, the lateralization index was higher (29.9 ± 7.4 vs. 10.3 ± 3.6, P < 0.02) in the APA with the mutation than in the APA without the mutation. CONCLUSIONS APA patients with the somatic KCNJ5 mutations showed a higher production of aldosterone than those without such mutations, which translates in a higher lateralization index. Thus, they are more likely to be identified at adrenal vein sampling and therefore to receive adrenalectomy.
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3.
Mechanisms of unilateral STN-DBS in patients with Parkinson's disease : a PET study.
Arai, N, Yokochi, F, Ohnishi, T, Momose, T, Okiyama, R, Taniguchi, M, Takahashi, H, Matsuda, H, Ugawa, Y
Journal of neurology. 2008;(8):1236-43
Abstract
Bilateral symptoms and signs of Parkinson's disease (PD) are often improved by unilateral subthalamic nucleus deep brain stimulation (STN-DBS). However, the mechanism for such bilateral effects is unknown. This study was intended to examine effects of unilateral STN-DBS using positron emission computed tomography (PET) and to elucidate mechanisms for bilateral improvement achieved by unilateral stimulation.We conducted (18)F-fluorodeoxyglucose ((18)FDG) and (18)F-fluorodopa ((18)F-DOPA ) PET scans in PD patients whose bilateral limb symptoms and axial symptoms were improved by unilateral DBS. Two scans were performed in each PET study: when DBS was on and off. We compared those images using statistic parametric mapping (SPM) 99.The significant clinical improvement obtained by unilateral DBS was shown as improvements in bilateral motor limb, axial, and gait subscores of the Unified PD Rating Scale (UPDRS). Moreover, (18)FDG PET revealed significant metabolic increases in the ipsilateral ventrolateral thalamic areas and metabolic decrease at the contralateral globus pallidus interna (GPi). In contrast, (18)F-DOPA PET showed no significant differences between DBS on and off.Ipsilateral thalamic activation might induce ipsilateral motor cortical activation, which explains the improvement of contralateral limb symptoms. Furthermore, deactivation of the contralateral GPi might disinhibit the thalamus and contralateral motor cortex, which explains reduction of ipsilateral limb symptoms. These results suggest the mechanisms for bilateral improvement achieved by unilateral DBS.
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4.
Bilateral capacity for speech sound processing in auditory comprehension: evidence from Wada procedures.
Hickok, G, Okada, K, Barr, W, Pa, J, Rogalsky, C, Donnelly, K, Barde, L, Grant, A
Brain and language. 2008;(3):179-84
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Abstract
Data from lesion studies suggest that the ability to perceive speech sounds, as measured by auditory comprehension tasks, is supported by temporal lobe systems in both the left and right hemisphere. For example, patients with left temporal lobe damage and auditory comprehension deficits (i.e., Wernicke's aphasics), nonetheless comprehend isolated words better than one would expect if their speech perception system had been largely destroyed (70-80% accuracy). Further, when comprehension fails in such patients their errors are more often semantically-based, than-phonemically based. The question addressed by the present study is whether this ability of the right hemisphere to process speech sounds is a result of plastic reorganization following chronic left hemisphere damage, or whether the ability exists in undamaged language systems. We sought to test these possibilities by studying auditory comprehension in acute left versus right hemisphere deactivation during Wada procedures. A series of 20 patients undergoing clinically indicated Wada procedures were asked to listen to an auditorily presented stimulus word, and then point to its matching picture on a card that contained the target picture, a semantic foil, a phonemic foil, and an unrelated foil. This task was performed under three conditions, baseline, during left carotid injection of sodium amytal, and during right carotid injection of sodium amytal. Overall, left hemisphere injection led to a significantly higher error rate than right hemisphere injection. However, consistent with lesion work, the majority (75%) of these errors were semantic in nature. These findings suggest that auditory comprehension deficits are predominantly semantic in nature, even following acute left hemisphere disruption. This, in turn, supports the hypothesis that the right hemisphere is capable of speech sound processing in the intact brain.
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Comprehension of humor in primary agenesis of the corpus callosum.
Brown, WS, Paul, LK, Symington, M, Dietrich, R
Neuropsychologia. 2005;(6):906-16
Abstract
Individuals with agenesis of the corpus callosum (ACC) can, in some cases, perform normally on standardized intelligence tests. Nevertheless, recent studies suggest that individuals with ACC and normal IQ scores have deficits in domains of fluid and social intelligence. Anecdotal reports from families suggest diminished appreciation of the subtleties of social interactions, and deficits in the comprehension of jokes and stories. In this research, both the cartoon and narrative joke subtests of a humor test (developed by Brownell et al. [Brownell, H., Michel, D., Powelson, J., & Gardner, H. (1983). Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients. Brain and language, 18(1), 20-27] and Bihrle et al. [Bihrle, A. M., Brownell, H. H., Powelson, J. A., & Gardner, H. (1986). Comprehension of humorous and non-humorous materials by left and right brain-damaged patients. Brain and Cognition, 5(4), 399-411]) were given to 16 adults with complete ACC (all with IQs>80) and 31 controls of similar age and IQ. Individuals with ACC performed worse than controls on the narrative joke subtest (p<.025) when VIQ was controlled. However, on the cartoon subtest the two groups were not significantly different. Covarying age, forms of IQ, narrative memory, set-switching, and literal language comprehension did not substantially alter the group difference. However, covarying comprehension of nonliteral language and proverbs eliminated the difference, suggesting a common origin for the comprehension of jokes, nonliteral language, and proverbs, most likely related to capacity for understanding second-order meanings.
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Amelioration by mecobalamin of subclinical carpal tunnel syndrome involving unaffected limbs in stroke patients.
Sato, Y, Honda, Y, Iwamoto, J, Kanoko, T, Satoh, K
Journal of the neurological sciences. 2005;(1-2):13-8
Abstract
Our previous study showed that overuse of the nonparetic hand and wrist of the nonparetic side following stroke result in significantly more abnormal on the nonparetic side than on the hemiparetic side in terms of electrophysiologic indices of median nerve function. The purpose of this study was to evaluate the effects of the orally administered mecobalamin, an analogue of vitamin B12, for carpal tunnel syndrome (CTS) in the nonparetic side in patients following stroke. In a randomized open label and prospective study of stroke patients, 67 received of 1500 mug mecobalamin daily for 2 years, and the remaining 68 (untreated group) did not. At baseline, sensory nerve conduction velocity, motor nerve conduction velocity, sensory nerve action potentials (SNAP) at the wrist, palm-to-wrist distal sensory latency, palm-to-wrist SNAP, motor nerve conduction velocity compound motor action potentials, and distal motor latency of median nerve were significantly more abnormal on the nonparetic side than on the hemiparetic side or in controls. Before the treatment 21 patients (31%) of untreated and 20 patients (30%) of treated group met electrophysiologic criteria for CTS. Sensory impairment of the nonparetic side had lessened in the treated group. After 2 years, all electrophysiologic indices of nonparetic side were significantly improved in the treated group compared with those in the untreated group. The improvement from baseline of electrophysiologic parameters in sensory nerve in the treated group was greater than the improvement measured in motor nerve. There were no side effects. Oral mecobalamin treatment is a safe and potentially beneficial therapy for CTS in stroke patients.
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The influence of viewing eye on pseudoneglect magnitude.
McCourt, ME, Garlinghouse, M, Butler, J
Journal of the International Neuropsychological Society : JINS. 2001;(3):391-5
Abstract
Various factors influence the degree of leftward error (pseudoneglect) that typifies the performance of normal individuals in line bisection tasks. This experiment reveals that the eye through which stimuli are viewed also exerts a modulating influence on spatial attention, as indexed by significant alterations in the magnitude of pseudoneglect. Using a forced-choice tachistoscopic line bisection protocol, 24 participants (12 male; 12 female) bisected horizontally oriented lines (22.6 degrees w x 0.39 degrees h) presented to central vision in 3 conditions: left uniocular viewing (L), right uniocular viewing (R), and binocular viewing (B). Perceived line midpoint, a measure of bisection accuracy, deviated significantly leftward of veridical (p < .05) in all viewing conditions, confirming a tonic asymmetry of visuospatial attention in normal young observers. In addition, a significant influence of viewing condition was found (p < .05) where pseudoneglect was greatest in the L condition, followed by the B and R conditions, respectively. Analysis of the slopes of the psychometric functions revealed significantly greater bisection precision in the binocular versus uniocular viewing conditions (p < .05). The results are interpreted to suggest that phasic effects on spatial attention can be produced by uniocular viewing via asymmetric retinotectal projections. The results are consistent with activation-orientation theories of attentional asymmetry.
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Forearm metabolism during infusion of adrenaline: comparison of the dominant and non-dominant arm.
Simonsen, L, Stefl, B, Bülow, J
Clinical physiology (Oxford, England). 2000;(1):8-13
Abstract
Human skeletal muscle metabolism is often investigated by measurements of substrate fluxes across the forearm. To evaluate whether the two forearms give the same metabolic information, nine healthy subjects were studied in the fasted state and during infusion of adrenaline. Both arms were catheterized in a cubital vein in the retrograde direction. A femoral artery was catheterized for blood sampling, and a femoral vein for infusion of adrenaline. Forearm blood flow was measured by venous occlusion strain-gauge plethysmography. Forearm subcutaneous adipose tissue blood flow was measured by the local 133Xe washout method. Metabolic fluxes were calculated as the product of forearm blood flow and a-v differences of metabolite concentrations. After baseline measurements, adrenaline was infused at a rate of 0.3 nmol kg-1 min-1. No difference in the metabolic information obtained in the fasting state could be demonstrated. During infusion of adrenaline, blood flow and lactate output increased significantly more in the non-dominant arm (8.12 +/- 1.24 versus 6.45 +/- 1.19 ml 100 g-1 min-1) and (2.99 +/- 0.60 versus 1.83 +/- 0.43 micromol 100 g-1 min-1). Adrenaline induced a significant increase in oxygen uptake in the non-dominant forearm (baseline period: 4.98 +/- 0.72 micromol 100 g-1 min-1; adrenaline period: 6.63 +/- 0.62 micromol 100 g-1 min-1) while there was no increase in the dominant forearm (baseline period: 5.69 +/- 1.03 micromol 100 g-1 min-1; adrenaline period: 4. 94 +/- 0.84 micromol 100 g-1 min-1). It is concluded that the two forearms do not respond equally to adrenaline stimulation. Thus, when comparing results from different studies, it is necessary to know which arm was examined.