Papers by Lizelle Fletcher
Journal of Family Ecology and Consumer Sciences Tydskrif Vir Gesinsekologie En Verbruikerswetenskappe, 2011
Journal of Trauma & Dissociation
We investigate the types of childhood maltreatment, and abuser-abused relational ties that best p... more We investigate the types of childhood maltreatment, and abuser-abused relational ties that best predict a dissociative disorder (DD). Psychiatric in-patients (n=116; mean age=35; F:M=1.28:1) completed measures of dissociation and trauma. Abuse type and abuser-abused relational ties were recorded in the Traumatic Experiences Questionnaire. Multidisciplinary team clinical diagnosis or administration of the SCID-D-R to high dissociators confirmed DD diagnoses. Logit models described the relationships between abuser-abused relational tie and the diagnostic grouping of patients, DD present (n=16) or DD absent (n=100). Fisher"s exact tests measured the relative contribution of specific abuse types. There was a positive relationship between abuse frequency and the presence of DD. DD patients experienced more abuse than patients without DDs. Two combinations of abuse type and relational tie predicted a DD: childhood emotional neglect by biological parents/siblings and later emotional abuse by intimate partners. These findings support the early childhood etiology of DDs and subsequent maladaptive cycles of adult abuse. Enquiries about childhood maltreatment should include a history of emotional neglect by biological parents/siblings. Adult emotional abuse by intimate partners should assist in screening for DDs.
Journal of Trauma & Dissociation
We investigate the types of childhood maltreatment, and abuser-abused relational ties that best p... more We investigate the types of childhood maltreatment, and abuser-abused relational ties that best predict a dissociative disorder (DD). Psychiatric in-patients (n=116; mean age=35; F:M=1.28:1) completed measures of dissociation and trauma. Abuse type and abuser-abused relational ties were recorded in the Traumatic Experiences Questionnaire. Multidisciplinary team clinical diagnosis or administration of the SCID-D-R to high dissociators confirmed DD diagnoses. Logit models described the relationships between abuser-abused relational tie and the diagnostic grouping of patients, DD present (n=16) or DD absent (n=100). Fisher"s exact tests measured the relative contribution of specific abuse types. There was a positive relationship between abuse frequency and the presence of DD. DD patients experienced more abuse than patients without DDs. Two combinations of abuse type and relational tie predicted a DD: childhood emotional neglect by biological parents/siblings and later emotional abuse by intimate partners. These findings support the early childhood etiology of DDs and subsequent maladaptive cycles of adult abuse. Enquiries about childhood maltreatment should include a history of emotional neglect by biological parents/siblings. Adult emotional abuse by intimate partners should assist in screening for DDs.
Medicine & Science in Sports & Exercise, 2015
International Journal of Rheumatic Diseases, 2012
Aim To determine if there is a difference between autonomic cardiac control as measured by heart ... more Aim To determine if there is a difference between autonomic cardiac control as measured by heart rate variability (HRV) in females with rheumatoid arthritis (RA) compared to a healthy control group. Methods The RA group (45) and control group (39) were matched for age and BMI. Three techniques were used: time domain, frequency domain and Poincarè plot analysis. All possible confounding factors were excluded and the test environment strictly regulated. Results Basal heart rate was significantly higher in the RA patients. In the supine position significant differences existed between RA patients and controls (p ≤ 0.01). Indicators of parasympathetic activity showed significantly lower variation in the RA group (RMSSD=14.70, pNN50=0.50, SD1=10.50, HF(ms 2)=31) compared to controls (RMSSD=29.40, pNN50=7.8, SD1=20.9, HF(ms 2)=141.00). Indicators of sympathetic variation were also significantly lower in RA patients (SD2=36.70, LF(ms 2)=65) compared to controls (SD2=49.50, LF(ms 2)=175). In the standing position 8 variables indicated autonomic impairment by significant differences (p≤0.01) between the groups. The response of the RA group to an orthostatic stressor showed less vagal withdrawal, [p-values for RMSSD=0.038, pNN50=0.022, SD1=0.043 and HF(ms 2)=0.008 respectively]; and lower sympathetic response [p-values for SD2=0.001 and LF(ms 2)<0.001] when compared to controls. Conclusions An inability of the autonomic nervous system to efficiently compensate to internal and external environmental changes may predispose RA patients to arrhythmias thereby increasing cardiovascular mortality. All 3 methods used showed the same outcome, implying decreased HRV and thus an increased risk for arrhythmias in RA patients. Evaluating the autonomic nervous system might be critical in planning management of RA patients.
Journal for Language Teaching/ …, 2009
In tertiary education settings it is impe-rative for students to move confidently between the aca... more In tertiary education settings it is impe-rative for students to move confidently between the academic discourses of a variety of disciplines. Thus, it is merited to aim writing interventions at genres that straddle disciplinary boundaries. Following a survey on preferred genres and text ...
Military Medicine
Introduction: Mixed gender basic military training (BMT) is adopted to integrate the female South... more Introduction: Mixed gender basic military training (BMT) is adopted to integrate the female South African soldier into the military. This study aimed to assess gender differences before, during (12 weeks), and after a 20-week mixed BMT course and determine if BMT significantly reduced these differences. Methods: A total of 186 soldiers (114 male: mean age = 21.0 ± 1.1 year; 72 female: mean age = 20.5 ± 1.2 year) completed the BMT course and all anthropometric, physical fitness, explosive power, and hand grip strength measurements. Repeatedmeasures analysis of variance was used to model BMT data with main effects for gender comparison between males and females, and time main effect for evaluation of differences between weeks 1, 12, and 20 of BMT, as well as an interaction effect for differences in changes over time for males and females. Alpha was set at α ≤0.05. Results: Male soldiers were significantly taller (p < 0.001) and scored better in all measurements at the start of BMT, differences ranged from 1.6% to 50% between genders. Differences narrowed by up to 18.5% in aerobic, push-up, abdominal measurements, and to 4.6% in the South African National Defense Force fitness test. Differences in power output and hand grip strength remained unchanged. Conclusion: Large initial anthropometrical and physical fitness differences decreased but were still obvious at the end of BMT. BMT should bridge the physical gap between male and female soldiers to ensure they can all perform the same duties. The enforcing of equal minimum physical fitness requirements for acceptance into BMT; conditional acceptance into the military subject to the successful completion of a bridging course aimed at improving physical fitness in individuals who do not meet the minimum physical fitness requirements for acceptance; and developing a cyclic physical training program with different entry points, dependent on initial physical performance at the start of BMT, ensuring adequate progression and overload for all soldiers are possible avenues to explore to achieve this goal.
The number of hidden nodes is a crucial parameter of a feedforward artificial neural network. A n... more The number of hidden nodes is a crucial parameter of a feedforward artificial neural network. A neural network with too many nodes may overfit the data, causing poor generalization on d a t a not used for training, while too few hidden units underfit the model, and is not sufficiently accurate. The mean square error between the estimated network and a target function has a minimum with respect t o the number of nodes in the hidden layer, and is used t o measure t h e accuracy. In this paper a n algorithm is developed which optimizes the number of hidden nodes by minimizing the mean square error over noisy training data. The algorithm combines training sessions with statistical analyses and experimental design t o generate new sessions. Simulations show t h a t t h e developed algorithm requires fewer sessions t o establish the optimal number of hidden nodes than using the straightforward way of eliminating nodes successively one by one.
Influence of intense training program on cardio stress index
Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 2014
Armed service recruits are faced with many stressors, including a strenuous training regimen that... more Armed service recruits are faced with many stressors, including a strenuous training regimen that may have an impact on their physiological functioning. The Cardio Stress Index (CSI) is a noninvasive marker of the stress that the heart is experiencing. The aim of the study was to test the physiological impact of 20 weeks of intense training of armed service recruits, using CSI as a noninvasive biomarker of cardiac stress. Armed service recruits are faced with many stressors, including a strenuous training regimen that may have an impact on their physiological functioning. The CSI is a noninvasive marker of the stress that the heart is experiencing. The calculation of the CSI is based on the duration of vascular excitation (QRS duration), heart rate, heart rhythm and standard deviation of the duration of time between each successive cardiac cycle (RR-interval). The aim of the present study was to test the physiological impact of 20 weeks of strenuous training of armed service recruit...
Dissociative mental states are canonically associated with decreased temporal theta activity on spectral analysis of EEG
Journal of Trauma Dissociation the Official Journal of the International Society For the Study of Dissociation, Jul 1, 2013
Quantitative electroencephalographic (QEEG) changes relating to dissociative experiences have onl... more Quantitative electroencephalographic (QEEG) changes relating to dissociative experiences have only rarely been demonstrated, and dissociative states were not quantified in those studies. The aim of this study was to explore concurrent associations between quantified dissociative states and QEEG spectral parameters, in particular theta activity, in psychiatric patients. Fifty psychiatric patients completed the State Scale of Dissociation (SSD) immediately after a 15-min EEG recording. The EEG was assessed by conventional clinical visual analysis as well as by quantitative (QEEG) spectral analysis. Canonical analysis was performed between the set of SSD subscale scores and the following QEEG parameters: alpha-theta magnitude ratios, and relative as well as absolute theta magnitude obtained from right and left mid- to posterior-temporal and parieto-occipital derivations. The SSD transferred well to the present data in terms of reliability and internal criterion-related validity. The SSD and Dissociative Experiences Scale (DES) correlated significantly (r = .73, p &amp;amp;amp;amp;amp;amp;lt; .001). Conventional EEG analysis identified 29 EEGs (58%) as abnormal. The main abnormality in 23 EEGs was slowing, maximal temporally in half of these cases. Canonical analyses confirmed a statistically significant relationship between the dissociation variables (especially conversion and depersonalization symptoms) and the QEEG variables (especially relative theta magnitude in the temporal regions; R = .72, p = .03, for SSD-QEEG; and R = .66, p = .04, for DES-QEEG). Quantified dissociative mental states are positively canonically associated with decreased temporal theta activity and increased alpha-theta ratios on QEEG in psychiatric patients with a high tendency to dissociate. The potential implications of the dissociation-theta-alpha relationship for understanding normal attentional processes need to be studied further.
Ultra-Marathon Athletes at Risk for the Female Athlete Triad
Sports Medicine - Open, 2015
Worldwide female participation in ultra-endurance events may place them at risk for the female at... more Worldwide female participation in ultra-endurance events may place them at risk for the female athlete triad (FAT). The study objectives were to establish triad knowledge, occurrence of disordered eating and triad risk amongst participants of the 2014 89-km Comrades Marathon event. A survey utilising the Low Energy Availability in Females questionnaire (LEAF-Q) and Female Athlete Screening Tool (FAST) questionnaire was conducted on female participants in order to determine the risk. In addition, seven questions pertaining to the triad were asked in order to determine the athlete&#39;s knowledge of the triad. Athletes were requested to complete the anonymous questionnaire after written informed consent was obtained while waiting in the event registration queues. Statistical analyses included Pearson product-moment correlations, chi-square tests and cross-tabulations to evaluate associations of interest. Knowledge of the triad was poor with 92.5 % of participants having not heard of the triad before and most of those who had, gained their knowledge from school or university. Only three athletes were able to name all 3 components of the triad. Amenorrhoea was the most commonly recalled component while five participants were able to name the component of low bone mineral density. Of the 306 athletes included in the study, 44.1 % were found to be at risk for the female athlete triad. One-third of participants demonstrated disordered eating behaviours with nearly half reporting restrictive eating behaviours. There is a significant association between athletes at risk for the triad according to the LEAF-Q and those with disordered eating (χ (2)(1) = 8.411, p = 0.014) but no association (or interaction) between triad knowledge and category (at risk/not at risk) of LEAF-Q score (χ (2)(1) = 0.004, p = 0.949). More athletes in the groups with clinical and sub-clinical eating disorders are at risk for the triad than expected under the null hypothesis for no association. Only 7.5 % of the female Comrades Marathon runners knew about the triad despite 44.1 % being at a high risk for the triad. Therefore, education and regular screening programmes targeting these athletes are overdue. Postmenopausal athletes are at particularly high risk for large losses in bone mass if they experience chronic energy deficiency and hence require special focus.
Rheumatoid Arthritis (RA) is a chronic, inflammatory disease of unknown cause and primarily consi... more Rheumatoid Arthritis (RA) is a chronic, inflammatory disease of unknown cause and primarily considered a disease of the joints. However, a variety of extra-articular manifestations including cardiovascular (CV) involvement are well recognized.
To determine whether a relationship exists between the functional movement analysis (FMA) score a... more To determine whether a relationship exists between the functional movement analysis (FMA) score and lower-body injury rates in high-performance adolescent female football players. Method. Observations included a baseline FMA score and medical injury reports. Data were collected from 24 players' injury and illness records over a 38-week training period. All football injuries requiring medical attention (including stiffness, strains, contusions and sprains) and/or the removal from a session, leading to training restriction, were included in the study. Off-season weeks were excluded. Pearson's product-moment correlation coefficient was calculated to assess the strength of the linear relationship between the FMA score and the number of medical visits, and between the number of medical visits and the number of training-restriction days.
This Chapter reports the effects of a standardised, intensive physical training programme (energy... more This Chapter reports the effects of a standardised, intensive physical training programme (energy expenditure: 8485 kJ/day) on autonomic cardiac control of a large group of healthy participants (N=154). It was hypothesized that results of exercise induced changes on the autonomic nervous system (ANS) are dependent on the body position and should be assessed not only in the resting position. Heart rate variability (HRV) recordings were made in the supine, rising and standing positions. Analytical techniques used were time domain, frequency domain and non-linear (Poincaré) analysis. The results of this study, for the supine position, showed an increase in resting vagal control of the heart, and a general increase in HRV by exercise programs. It also showed, with the aid of deductive reasoning, that lower post-exercise heart rate may result, not only from the exercise-induced increase in vagal activity, but that a decrease in sympathetic control of the heart contribute to it. The exerc...
Heart rate variability (HRV) analysis is a popular tool for the assessment of autonomic cardiac c... more Heart rate variability (HRV) analysis is a popular tool for the assessment of autonomic cardiac control. These measurements are increasingly employed in studies ranging from investigations of central autonomic regulation; to studies exploring the link between psychological processes and physiological functioning; to the indication of ANS activity in response to exercise, training and overtraining. Many publications elaborate on the effect of exercise on HRV and by implication on cardiac functioning. However, results on the effects of exercise on the autonomic control of the heart are often contradictory and incomplete in the normal population and in disease. In order to understand and employ the effects of exercise in patients with cardiovascular disorders it is of primary importance that agreement should be reached on the effects of exercise in the normal and healthy population. In this chapter, a selection of older and more recent publications, investigating autonomic training eff...
satnt.v32i1.769 Oorspronklike Navorsing: Voedsel 'n Vergelyking tussen die kardiostres-indeks... more satnt.v32i1.769 Oorspronklike Navorsing: Voedsel 'n Vergelyking tussen die kardiostres-indekse van 'n aktiewe en 'n sedentêre populasie Authors: Peet du Toit Die moderne leefwyse bring dikwels mee dat ons die belangrikheid van liggaamlike oefening uit die oog verloor. Ons toenemend passiewe leefwyse het gelei tot 'n aansienlike toename in die voorkoms van lewenstylsiektes soos hipertensie en verskeie vorme van vaskulêre patologie. In hierdie studie word die kardiostres-indekse (KSI'e) van aktiewe en sedentêre individue met mekaar vergelyk ten einde insig te verkry in die uitwerking van die aansienlike veranderinge wat in die gemoderniseerde samelewing plaasgevind het. Die aktiewe populasie het bestaan uit 217 weermagrekrute wat reeds 20 weke van hul basiese weermagopleiding voltooi het. Die (n = 126) lede van die sedentêre populasie is gewerf uit 'n tradisionele tersiêre onderwysinstansie. Die deelnemers uit beide populasies moes drie toetssessies bywoon wat ...
Frontiers in Physiology, 2013
Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate varia... more Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO 2 max and the following: HR, HRV indicators, and HR normalized HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO 2 max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO 2 max. Only HR, RR interval, and pNN50 showed significant (p < 0.01, p < 0.01, and p = 0.03) correlations with VO 2 max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO 2 max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator) added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalized indicators, HR explained of the largest percentage of the changes in VO 2 max (16.5%). Thus, HR on its own is the most important predictor of changes in an important cardiac health metric such as VO 2 max. These results may indicate that during investigation of exercise ability (VO 2 max) phenomena, quantification of HRV may not add significant value.
South African Journal of Sports Medicine, 2014
Background. Non-traumatic bicycle injuries are common. However, research available on non-traumat... more Background. Non-traumatic bicycle injuries are common. However, research available on non-traumatic injuries in amateur cyclists is more than a decade old, and most of the research on this topic has been done in Europe and America on professional cyclists in multi-day cycling events. An understanding of the common injuries may lead to appropriate prevention intervention. Objective. To determine the incidence of overuse injuries in amateur cyclists preparing for participation in a 1-day cycle challenge. Methods. A questionnaire was emailed to participants of the 2012 Momentum 94.7 Cycle Challenge, which amateur participants ≥18 years old were invited to complete. Data on demographics, training habits and the participants' injury profile in the preceding year were collected. Results. Of the 3 300 respondents, 75% were male and 59% were between 30 and 50 years old. Non-traumatic injury, pain or neurological symptoms were reported by 88% of the respondents. The percentages of all respondents who experienced problems in the following anatomical areas were as follows: neck 34%, back 41%, hand/wrist 41%, buttock/perineum 41%, hip 7%, knee 33% and foot/ankle 24%. Knee pain was responsible for the need to stop training for the largest percentage of respondents. Neurological complaints were common in respondents who experienced neck, back, hand/wrist, buttock/perineum and foot/ankle problems. Conclusion. Non-traumatic injuries in amateur cyclists are common, with back, hand/wrist and buttock/perineal symptoms the most frequent problems. Knee problems caused the greatest need to stop training and seek medical help.
Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 2013
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Papers by Lizelle Fletcher