Dissertation submitted in partial compliance with the requirements for the Masters Degree in Technology: Chiropractic, Durban Institute of Technology, 2006. / Neck pain is a common complaint and a common source of disability in the general population with a point prevalence of nearly 13%. Reports indicate that industry related neck disorders (lifetime incidence of nearly 50%) account for as many days of absenteeism as low back pain; one could compare the two clinical conditions in terms of these trends on a global scale. To investigate whether similar trends do exist, 200 participants with neck pain and 200 asymptomatic participants (stratified sampling according to age and gender) that consented to the research were clinically assessed. These participants also completed a questionnaire addressing the factors that have been identified as related to neck pain at the consultation where they were assessed. This research did not involve the treatment of the participants, although a free treatment was given for patients that opted for one or to those that required it post participation in the study. If treatment was outside the scope of the chiropractic clinic, the participants were referred to the appropriate health care provider. The aim of the study was to investigate factors associated with neck pain in the indigenous African population in the greater Durban area. Data was analysed according to the following: Descriptive statistics were interpreted by means of frequency tables, pie charts, bar graphs and / or in a tabular format in order to describe the sample characteristics of the population under study. Inferential statistics included regression analysis in order to determine any relationships between the patient‟s neck complaint characteristics and factors associated with the complaint. SPSS version 11.5 was used for data analysis (SPSS Inc, Chicago, Ill, USA). A p value of <0.05 was considered as statistically significant. Descriptive analysis involved presenting or graphing categorical variables as counts and percentages, and quantitative variables as medians and interquartile ranges due to the skewness of the data. Associations between factors and neck pain were examined bivariately using Pearson‟s chi square or Fisher‟s exact tests as appropriate for categorical factors, or Mann-Whitney tests in the case of quantitative non-parametric data. Finally in order to examine the adjusted independent effects of all factors which were found to be individually significant in the bivariate analysis, multivariate binary logistic regression analysis was done. A backwards elimination modelling technique was used, based on likelihood ratios, with entry and exit probabilities set to 0.05 and 0.010 respectively. Results were reported as odds ratios, 95% confidence intervals and p values. Chi squared analyses was utilised to assess the strength of the relationship and the degree of significance of the relationship. All statistics were analyzed at a confidence interval of 95% and a level of significance where α ≤0.05 (pvalue). The symptomatic participants seemed to be less well educated than the controls. The cases seemed to be less in full time employment, less unemployed, and more self employed than the controls. Income was unevenly distributed among cases and controls. The cases who were working seemed to earn less than the controls who were working. The duration of having neck pain was mainly 1 month. The majority of cases classified their pain as mild. Most participants felt that their pain was worst in the afternoons or related to activities, while they felt their pain was least in the mornings. Frequency of neck pain was mainly constant (36.5%), followed by frequent (32.5%) and seldom (25%). Symptomatic participants mostly reported that their pain began without injury, gradually in 67.5% and abruptly in 13.5%. Fewer symptomatic participants reported pain beginning after an injury (n=22 gradually and n=7 abruptly). The majority reported their neck pain to be stable (38%), while 34% felt it was getting worse and only 19% getting better. More than half of the cases reported difficulty with work due to neck pain. Fewer reported difficulties with daily activities such as washing (30%), sleeping (26%), and lifting (24%). Almost half of the cases rated their disability as none (48%). Only 16% reported severe disability. Thirty-three percent (n=66) reported having been absent from work due to neck pain. The duration of absence in those who were absent was mainly 0-1 week (89.4%). 59 (29%) reported being bed-ridden with neck pain. The most frequent duration was also 0-1 week (81.4%). Ninety three point five percent reported no change in occupational status, while 6 (3%) were demoted, 5 (2.5%) boarded, and 2 (1%) fired. With respect to associated signs and symptoms, 156 (78%) reported to suffer from headaches. In addition, symptomatic participants were asked if they associated their neck pain with any other activities. The most commonly reported factor was stress (22%), followed by bad posture (17%). The other reported factors were reported infrequently. Participants who worked in occupations that involved driving, turning neck, answering the telephone, working in an air-conditioned room, and bending over a desk were significantly more at risk of being cases than controls. Non-occupational factors which were associated with neck pain were worrying a lot, motor vehicle accident, not enough bed support, not using arms to support a book, sitting without back or arm support, not watching TV a lot, and exercising. The results of the study suggest that neck pain within the indigenous African population is associated with the level of education, income, stress levels, bad posture, repetitive movements of the neck, and motor vehicle accidents. It was also found that most of neck pain patients do suffer from headaches. The findings show that neck pain is mostly classified as mild in nature with 1 month duration. Although neck pain was reported to be responsible for at least 7 days of absenteeism from work, causing difficulty with daily activities, most patients reported no disability as a result of neck pain.

Emergency ejection of an air crew member from military aircraft in flight places dangerously large vertical acceleration forces on the body of the member. The additional mass on the head due to Night Vision Goggles and Helmet Mounted Displays increases the vulnerability of the head/neck system to injury. To eliminate the need for human testing, computer simulations of biodynamic head and neck system response to large vertical accelerations have been produced. A head/neck characteristic was developed which included the rotation and axial deformation properties of the cervical spine. The characteristic consisted of three rigid segments representing the head, neck, and upper torso, a ball-and socket joint representing the head/neck articulation, and a slip joint representing the neck/torso articulation. The model was exercised using the Articulated Total Body Model developed by Calspan Corporation and Armstrong Laboratory. The model parameters were determined using human vertical deceleration test data acquired at Armstrong Laboratory. Simulations of human biodynamic response to ejection acceleration show the proposed head/neck characteristic to produce improved correlation with human biodynamic response to 10 Gz acceleration when compared to previous rigid body models of the human head/neck system. / Master of Science