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Biomedical subjects

G A Ryan

Publications and source records attributed to G A Ryan.

At least 19 recordsLinked to original sources
PubMed2000

Road safety issues in remote Aboriginal communities in Western Australia.

A series of interviews with the chairpersons of Aboriginal communities in a remote area of Western Australia were conducted to examine their attitudes to road safety problems. It was found that some road safety issues that were expected to be considered problems were not necessarily seen to be so by those interviewed. This finding suggests that the first stage of a road safety intervention program for Aboriginal people may need to include an awareness raising component. It also suggests that there is a need for more detailed research defining particular problems more accurately before effective and culturally appropriate countermeasures are developed.

Accidents, Traffic↗
PubMed1998

Age related changes in drivers' crash risk and crash type.

Age and gender differences in the rates of crash involvement of Western Australian drivers were examined using the Road Injury Database of the Road Accident Prevention Research Unit at the University of Western Australia. The population examined was all drivers of cars, station wagons and related vehicles involved in property damage, injury and fatal crashes reported to the police in Western Australia from 1 January 1989 to 31 December 1992. It was found that drivers aged < 25 years were involved in ca 35% of crashes, compared with 3% for drivers 70 years and over. Drivers under 25 years had the highest rates on a population and licence basis, but when the distance travelled was taken into account, rates of crash involvement for the 75 or more age group were as high as those of the youngest age group. Females had higher rates of crash involvement than males in all age groups. Drivers over 70 years were involved in relatively more crashes involving fatalities and hospital admissions than younger drivers, although the number of such crashes was small. The youngest groups of drivers had proportionately more single vehicle crashes, drivers 30-59 years had more same direction crashes, and drivers over 60 years, particularly those over 75 years, had more direct and indirect right angle crashes. There were also age related patterns in the movements associated with these crashes. Drivers under 30 years were associated with swerving and swinging wide, drivers 30-59 years were stopped at the time of the crash disproportionately often, and drivers over 60 years were associated with turning movements. The percentage of crashes in daylight ranged from ca 64% for drivers under 20 years to a maximum of over 90% for those 80 years and over. These patterns are consistent with changes in exposure to risk of crash involvement with age, and also with changes in ability, experience and psychological function, which are also related to age.

Accidents, Traffic↗
PubMed1997

MRI of car occupants with whiplash injury.

Our purpose was to document and investigate the prognostic significance of features seen on MRI of patients with whiplash injury following relatively minor road traffic crashes. MRI was obtained shortly and at 6 months after the crash using a 0.5 T imager. The images were assessed independently by two radiologists for evidence of fracture or other injury; loss of lordosis and spondylosis were also recorded. Clinical examinations were used to assess the status of patients initially and at 6 months. The results of the independent MRI and clinical investigations were then examined for association using statistical tests. Initial MRI was performed on 29 patients, of whom 19 had repeat studies at 6 months; 48 examinations were thus examined. Apart from spondylosis and loss of lordosis, only one abnormality was detected: an intramedullary lesion consistent with a small cyst or syrinx. There were no statistically significant associations between the outcome of injury and spondylosis or loss of lordosis. No significant changes were found when comparing the initial and follow-up MRI. It appears that MRI of patients with relatively less severe whiplash symptoms reveals a low frequency of abnormalities, apart from spondylosis and loss of lordosis, which have little short-term prognostic value. Routine investigation of such patients with MRI is not justified in view of the infrequency of abnormalities detected, the lack of prognostic value and the high cost of the procedure.

Accidents, Traffic↗
PubMed1996

An evaluation of road crash injury severity measures.

Reliable and consistent measures of injury severity are necessary for the study of environmental, crash and personal factors involved in road traffic crashes. This study was designed to evaluate measures of injury severity derived from computerized hospital discharge records, using 3609 road crash casualties admitted to hospital in Western Australia in 1988. External cause of injury codes were used to identify injuries from road traffic crashes. The ICDMAP software was used to convert the diagnosis codes into Abbreviated Injury Scale (AIS) scores for each body region. The maximum AIS values were derived using (1) all 12 diagnosis codes; (2) the first six diagnosis codes; and (3) the principal diagnosis code alone. Other measures of injury severity evaluated were the number of body regions with at least one injury; the number of regions with Abbreviated Injury Severity score of three or more; and total number of days spent in hospital. Discriminant analysis suggested that the AIS could be separated into minor and major injuries at a score of three and the Injury Severity Score at a score of nine. The measures derived from the AIS were all strongly correlated with each other and with the length of hospital stay and the dichotomized values gave similar results to the other scores when used in regression analyses of the injury experience of different types of road users. It was concluded that measures incorporating elements of both severity and number of injuries were preferable but length of hospital stay would be a suitable proxy if no other injury information was available.

Accidents, Traffic↗
PubMed1996

Comparison of accident and emergency with police road injury data.

This paper examines the consistency of police and hospital reporting of outcomes of road traffic crashes using a database of linked police crash reports and accident and emergency department data. The database used consisted of linked records of road traffic crashes in Western Australia for the period of October 1, 1987 to December 31, 1988 from police reported casualty crashes, the discharge records from all hospital admissions in Western Australia, the Registrar-General's death records, and records for each ambulance trip as a result of a road crash in the metropolitan area of Perth. The results suggest that police records of hospital admissions from the group of accident and emergency attendances underestimated the total by approximately 15%.

Accidents, Traffic↗
PubMed1995

Field and analytic observations of impact brain injury in fatally injured pedestrians.

To develop more effective head protection against impact injury, maximum levels of mechanical impact or injury tolerance criteria, or both, should be specified for particular levels of injury and for particular structures of the brain. By using a development of an existing very simplified model of the head-vehicle impact for pedestrians we were able to make estimates of the peak angular acceleration and change in angular velocity of head impacts for fatally injured pedestrians. This model also enabled us to examine the relationship between the parameters of the impact, and the critical strain curves for brain injury proposed by Margulies and Thibault (1992). It was found that the offset of the impact from the center of mass of the head was a major influence, and, in addition, in impacts with a combined head/vehicle stiffness above 130 kN/m, the head impact velocity and change in head angular velocity were important, whereas for impacts with lower stiffness, the stiffness of the impact structure and hence, peak angular acceleration, were the major influences. Transformed into the frequency domain, the 130 kN/m region corresponds roughly to a harmonic of the natural frequency of the brain and skull, and the change in behavior may be related to decoupling of the skull and brain at impact. In 12 cases of lateral head impact, all but one case with visible injury in the corpus callosum were found to lie close to or above the 10% critical strain curve. Despite the very wide error limits around each data point, there is sufficient consistency between the field observations of brain injury and the analytic findings to suggest that the 10% critical strain curve represents a threshold for brain injury, expressed in terms of peak angular acceleration and change in angular velocity.

Brain Injuries↗
PubMed1994

A method of estimating linear and angular accelerations in head impacts to pedestrians.

In order to investigate the relationship between impact to the head and brain injury, we have developed a method, using information obtained from reconstruction of the collisions, of estimating the peak linear and angular accelerations of the head for pedestrian impacts on a vehicle. This information includes the location of the impact on the head, the impact velocity of the head, and the stiffness of the struck surface. In developing the method we assumed that the velocity of the head on striking the vehicle was the same as the velocity of the vehicle itself, that the force vector was normal to the surface of the skull, that the force-deflection curve characterising the combined response of the impacted surfaces was linear, and that the kinetic energy of the head immediately prior to impact was converted into strain energy in deforming the head and the vehicle structure. Only the loading phase of the impact was considered, there was no assumption of an elastic unloading phase. Using cadavers, the validity of these assumptions and hence the usefulness of the method were tested by comparing the estimates of peak linear acceleration with the results of 18 pedestrian-vehicle impact reconstructions. On average, the method underestimated the experimental values by about 15%, with a range of +/- 35%. The results from the application of this method are currently being used to study the relationship between the magnitude and direction of the impact to the head and the distribution and severity of the brain injury resulting from actual collisions.

Acceleration↗
PubMed1994

Mechanisms of brain injury related to mathematical modelling and epidemiological data.

Measurements of the frequency response of head impact points on the exterior and the interior of a car were used to characterize the dynamic behavior of the object that was struck. These points were then arranged in a hierarchy of increasing stiffness. Thirty-two cases in which the distribution of injury to the brain had been recorded were grouped according to the stiffness of the object struck and by the location of the impact on the head. The distribution of the brain lesions were determined for each class of stiffness and location of impact. Three probable mechanisms of brain injury were distinguished: relative motion between the brain and the skull, local bone deformation, and intracerebral stresses. Each mechanism was related to a range of stiffness and natural frequency of the structure impacted. These theories of brain injury mechanisms are consistent with observed epidemiological data and with conclusions drawn from mathematical modelling.

Accidents, Traffic↗
PubMed1994

Neck strain in car occupants: injury status after 6 months and crash-related factors.

In this study, 29 individuals who sustained a neck strain as a result of a car crash were drawn from a group of physiotherapy and general practices and were followed up after 6 months. The aim was to examine relationships between the state of the neck injury at the time of follow up and crash-related factors, notably crash severity and occupant awareness. Crash severity was assessed by measurement of damage to the involved vehicles, while 6-month injury status was established through physical examinations and interviews. No statistically significant associations between crash severity and 6-month injury status were found, but subjects who were unaware of the impending collision had a greatly increased likelihood of experiencing persisting symptoms of and/or signs of neck strain, compared with those who were aware (odds ratio = 15.0; 95 per cent confidence limits: 1.8, 178). While the role of crash severity in the production and duration of neck strains remains unclear, awareness appears to have a strong protective influence and may prove to be a useful prognostic indicator in clinical settings.

Accidents, Traffic↗
PubMed1994

Brain injury patterns in fatally injured pedestrians.

To study the relationship between the severity of impact to the head and the severity and distribution of injury to the brain in fatally injured pedestrians, events in vehicle-pedestrian collisions were reconstructed to determine the peak linear and angular acceleration sustained by the pedestrians' heads. The nature and distribution of injuries to the brain were determined by neuropathologic examination of coronal sections of the brain. Study of 13 cases with occipital impacts and 18 with lateral impacts showed that the brain appeared to be more susceptible to injury from lateral impacts. The frontal and temporal regions appeared to be more susceptible to injury at low accelerations in occipital impacts, providing an explanation for "coup" and "contrecoup" injuries. For occipital impacts, a positive relationship was found between linear acceleration and the extent of injury to the brain, suggesting that there was a threshold for observable and concussive brain injury at about 1500 m/s2 peak linear acceleration. These findings are important for the development of measures for preventing brain injuries.

Accidents, Traffic↗
PubMed1993

Neck strain in car occupants. The influence of crash-related factors on initial severity.

OBJECTIVE: To examine the relationship between the initial severity of neck strain in car occupants and crash-related factors, in particular, crash severity. DESIGN/PARTICIPANTS: Thirty-two individuals with neck strain after a car crash, drawn from physiotherapy and general practices in metropolitan Adelaide, were interviewed about their experience and examined by a manipulative physiotherapist. Crash severity was assessed by measurement of damage to the involved vehicles. MAIN OUTCOME MEASURES: Five measures of neck strain severity were obtained: number of body regions with symptoms, number of positive responses to palpation, cervical range of motion, subject's own rating on an analogue pain scale, and examiner's severity rating. Two measures of crash severity were used: maximum residual deformation, and velocity change of the subject's vehicle. RESULTS: Neck strain was observed in individuals who were involved in crashes of low severity. Maximum residual deformation of the vehicle was negatively associated with the subject's cervical range of motion and positively associated with the other measures of neck strain severity. For rear impacts, both measures of crash severity were associated with measures of neck strain severity. The group of subjects who were aware of the impending collision had a greater range of cervical spine movement and fewer positive responses to palpation than those who were unaware. CONCLUSIONS: Initial severity of neck strain is positively correlated with crash severity. Awareness of the impending collision may have a mitigating effect on injury severity.

Accidents, Traffic↗
PubMed1993

The effect of random breath testing on perception of likelihood of apprehension and on illegal drink-driving.

This study examines the links between random breath testing (RBT), driver perception of the likelihood of apprehension if illegally drink-driving, and drink-driving behaviour in Adelaide, South Australia. It is based on information gained from surveys of night-time drivers in metropolitan Adelaide, during 1987, 1989 and 1991. Overall, about 25% of the sample in each year thought that illegal drink-driving was likely to result in apprehension. This perception was consistently lower for males and for those aged less than 30 years than for their counterparts, however, there was evidence that it increased with exposure to RBT, notably when that exposure was recent. Also, compared with other drivers, fewer drivers who thought that apprehension was likely had an illegal blood alcohol concentration (BAC) when surveyed, or reported that they would be likely to drive if they thought that they had an illegal BAC. However, the majority of drivers who thought that detection was unlikely also reported that they would be unlikely to drink-drive. These results suggest the need for some re-direction of current RBT activities.

Journal Article↗
PubMed1992

Human factors in rural road crashes.

An in-depth study of 79 vehicle crashes on rural roads in an area of about 100 km radius around Adelaide examined sociodemographic and psychophysiological characteristics of the drivers and riders involved. In many respects this sample of crashes was similar to a much larger number of police-reported crashes in the same area but included: relatively more crashes with severe or fatal injuries; more crashes on divided roads, on sealed roads and on curves; and more crashes involving trucks. Alcohol and lack of seat belt use were shown to be major problems in these rural crashes. The drivers and riders most strongly associated with these particular problems were males, in blue collar occupations and with limited education; they tended to be aged 30 years or more in the case of alcohol abuse, and were likely to be under 30 years in the case of restraint misuse. The attitudes of these drivers and riders, and other characteristics likely to have contributed to their involvement in a crash, are discussed. There is a need to develop specific and effective countermeasures to reduce drink-driving and increase seat belt wearing in rural areas.

Accidents, Traffic↗
PubMed1989

The prevalence of musculo-skeletal symptoms in supermarket workers.

The Victorian Branch of the Shop Distributive and Allied Employees Association became concerned in 1985 by the large number of cases of musculo-skeletal symptoms being reported by members working in food and grocery supermarkets. With the support of the Victorian Occupational Health and Safety Commission a survey was carried out which was aimed at determining the prevalence of such symptoms, and identifying associated factors. A questionnaire designed to establish the presence of musculo-skeletal symptoms was administered to all employees of seven supermarkets ranging in size from 15 to 171 employees, with a response rate of 73%. The staff of supermarkets were predominantly young, female and transient. One-third reported regular symptoms in some part of their body. Prevalence rates were calculated for body area and department. The checkout department had the highest rates for almost all body areas. The lower back, lower limbs and feet were the body areas with the highest rates. Postures and activities of a sample of job categories in each department were sampled at 10 s intervals for periods of 30 min for a total of 1000 observations for each department. A positive and significant correlation was found between proportion of time spent standing and symptoms in the lower limb and foot, especially in the checkout department where 90% of the time was spent standing in one place. It was concluded that there was an excess of symptoms appearing in checkout operators, and therefore, the operating methods of the checkout department warrant revision.

Adult↗
PubMed1989

Road crash cervical injuries. A radiological study of fatalities.

A lateral radiograph of the cervical spine was obtained for 174 of the 207 persons killed in road crashes in Adelaide, South Australia, during the 12-month period of June 1, 1987 to May 31, 1988. Of the total of 57 cases of cervical injury, routine postmortem examination identified 30 cases (52.6%), and the radiographic examinations identified 51 cases (89.5%). In the cases where it was performed, radiography identified 96.2% of injuries. One-half of injuries of level C3 and above were not reported at postmortem examination, compared with 22% of those occurring below this level. This finding correlates with the physical difficulties of examining the upper part of the cervical spine. This study has shown that lateral cervical radiography is a simple and effective method of more accurately identifying significant cervical spinal injuries, thus improving greatly the value of postmortem examinations in determining the patterns and mechanisms of these injuries.

Accidents, Traffic↗
PubMed1989

Cervical spine injuries in road traffic crashes in South Australia, 1981-86.

The records of all cases of injury to the cervical spine sustained in road crashes for the 6 year period (1 January 1981 to 31 December 1986) which were admitted to the Spinal Injuries Unit of the Royal Adelaide Hospital, to the Adelaide Children's Hospital, or were identified at post-mortem examination were examined, and the relevant data extracted. There were 291 cases in the non-fatal group, and 161 in the fatal group. These represent a complete enumeration of all such patients in the state of South Australia over the 6 year period, given that up to 50% of cervical injuries in fatal cases can be missed. Comparison of the two groups showed that the fatal group had a much higher proportion of pedestrians, and persons over 50 years of age. About one-half of the fatal group had injuries at the level of C1 or the atlanto-occipital articulation. The most frequent level of injury in the non-fatal group was C2 (29.2%). About 30% of the non-fatal cases had some spinal cord damage. Case fatality rates were calculated, and ranged from 100% for injury at the atlanto-occipital articulation to 8% at C2. The fatality rate of pedestrians was about 4 times higher than that of vehicle occupants. About three-quarters of all cervical spine injuries occurred in vehicle occupants. There was an increase in the number of cases occurring in each year of the period studied. This rise was noted in non-fatal cases, in males, in vehicle occupants, and in crashes in the country.

Accidents, Traffic↗
PubMed1976

Blood alcohol and road trauma survey.

Since April 8, 1974, Victorian legislation has required that blood samples be taken from all persons aged 15 years or over after a road traffic crash. A survey was carried out of 474 such persons from June 10 until September 12, 1974. Of these, blood was taken from 350, and estimates of blood alcohol concentration were obtained from 271 samples. Sixty-five samples of the 271 (24%) gave positive results for alcohol and in about two-thirds of these the levels were higher than the legal limit of 0-05 g/100 ml. Over half of the subjects with positive results for blood alcohol concentration were under 30 years of age, 80% were males, and half were car drivers. This contrasted with the "alcohol-negative" subjects, who were older, and about half of whom were males. About 60% of both groups received minor injuries, and about 20% were admitted to hsopital. Research is continuing to define drinking habits and other social characteristics of these groups.

Accidents, Traffic↗