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Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication
Dissertation (MSc)--University of Pretoria, 2009.
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University of Pretoria
2013
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| _version_ | 1867613691183104000 |
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| access_status_str | Open Access |
| author2 | Viljoen, Margaretha |
| author_browse | Viljoen, Margaretha |
| author_facet | Viljoen, Margaretha |
| collection | Thesis |
| dc_rights_str_mv | © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria |
| description | Dissertation (MSc)--University of Pretoria, 2009. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/26102 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:40:10.037Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/26102 Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication Viljoen, Margaretha s24087905@tuks.co.za Negrao, Bianca Lee Sympathovagal balance Autonomic nervous system Ritalin Methylphenidate Electrocardiograms Theta/beta ratios Adhd Theta/smr ratios Alpha waves Focussed attention Heart rate variability Skin conductivity Cardiac function Blood pressure UCTD Dissertation (MSc)--University of Pretoria, 2009. Indications are that autonomic under-arousal exists in children with ADHD. Published results are, however, controversial and few studies examine the relationship between the autonomic nervous system and focussed attention. In line with the indications of sympathetic under-arousal, patients with the disorder are treated with sympathomimetic stimulants such as Ritalin (methylphenidate). Since these medications stimulate the sympathetic nervous system, they possess the potential to influence cardiac function. The aims of this study were a) to assess autonomic nervous system functioning in 20 children with ADHD, as compared to controls, and to examine the effects of focussed attention and sympathomimetic medication on this system, b) to investigate cardiac functioning in 20 children with ADHD, as compared to controls, and to examine the effects of sympathomimetic medication on this system and c) to assess EEG functioning in children with ADHD, as compared to controls, and to examine the effects of sympathomimetic medication on this functioning. Children with ADHD were tested while they were stimulant-free and during a period in which they were on stimulant medication, while controls were tested once. Autonomic nervous system activity of the children was assessed at baseline and during focussed attention by means of heart rate variability (HRV) and skin conductivity. Attention was evoked by means of a program on the BioGraph Infiniti biofeedback apparatus, which is used specifically to train ADHD individuals to increase their attentive abilities. HRV was determined by time-domain, frequency-domain and Poincaré analysis of RR interval data. Skin conductivity was determined by BioGraph Infiniti biofeedback apparatus. Cardiac functioning of the children was assessed at baseline by means of blood pressure recordings and electrocardiograms (ECGs). Blood pressure was measured by means of a stethoscope and mercurial sphygmomanometer. ECGs were obtained by means of a Schiller CardioLaptop AT-110 ECG recorder using the standard 12-lead cable positioning for a resting ECG and parameters measured included HR, RR, QT, JT, QTc, JTc, QTd, JTd, QTcd and JTcd. EEG values were determined at baseline and during focussed attention by means of BioGraph Infiniti biofeedback apparatus. EEG values measured in this study included theta/beta ratios, theta/SMR ratios and thalpha, low alpha and high alpha power. The main findings of this study are that: <ul> <li>Stimulant-free ADHD children show a parasympathetic dominance of the sympathovagal balance relative to controls.</li> <li>Methylphenidate usage shifts the autonomic balance of children with ADHD towards normal levels; however a normal autonomic balance is not reached.</li> <li>Stimulant-free ADHD children exhibit a shift in the sympathovagal balance towards the sympathetic nervous system from baseline to focussed attention; however, methylphenidate abolishes this shift.</li> <li>Methylphenidate usage does not, in general, cause QTc or JTc prolongation but it may cause QTc or JTc prolongation in susceptible individuals.</li> <li>Children with ADHD can not be differentiated from normal children on the basis of theta/beta ratios, theta/SMR ratios or alpha power.</li> <li>Methylphenidate increases the level of centering in children with ADHD.</li> <li>Stimulant-free ADHD children display an alpha block from baseline to focussed attention; however, methylphenidate abolishes this alpha block.</li></ul> Copyright Physiology unrestricted 2013-09-07T02:32:04Z 2009-08-04 2013-09-07T02:32:04Z 2009-04-18 2009-08-04 2009-07-07 Dissertation Negrao, BL 2008, Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/26102 > E1323/gm http://hdl.handle.net/2263/26102 http://upetd.up.ac.za/thesis/available/etd-07072009-163036/ © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria application/pdf University of Pretoria |
| spellingShingle | Sympathovagal balance Autonomic nervous system Ritalin Methylphenidate Electrocardiograms Theta/beta ratios Adhd Theta/smr ratios Alpha waves Focussed attention Heart rate variability Skin conductivity Cardiac function Blood pressure UCTD Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title | Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title_full | Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title_fullStr | Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title_full_unstemmed | Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title_short | Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of sympathomimetic medication |
| title_sort | autonomic correlates at rest and during evoked attention in children with attention deficit hyperactivity disorder and effects of sympathomimetic medication |
| topic | Sympathovagal balance Autonomic nervous system Ritalin Methylphenidate Electrocardiograms Theta/beta ratios Adhd Theta/smr ratios Alpha waves Focussed attention Heart rate variability Skin conductivity Cardiac function Blood pressure UCTD |
| url | http://hdl.handle.net/2263/26102 http://upetd.up.ac.za/thesis/available/etd-07072009-163036/ |