An investigation of health behavior change in Vietnamese-born individuals living in Sydney, Australia.

OBJECTIVE: The purpose of this study was to look at rates of acculturation among Vietnamese immigrants, with particular emphasis on health behaviors. DESIGN: A volunteer sample was surveyed. SETTING/PARTICIPANTS: The participants were drawn from inner and western Sydney, Australia. Participants were asked for their perception of their English fluency as a measure of likely exposure to health promotion advertising and their food, social, exercise, drinking, and smoking habits. RESULTS: It was found that the longer the Vietnamese immigrants participants had lived in Australia, the less likely they were to smoke; in fact, the smoking rate of this population is as low as that of the Australian population as a whole. However the immigrants did not change their low rate of alcohol consumption. In addition, the Vietnamese who had lived longer in Australia significantly increased their daily exercise and started to eat more take-away foods. CONCLUSIONS: With respect to health promotion, these changes are mixed: smoking has decreased, but half the group had begun eating take-away foods; this factor, if combined with a lack of exercise, is likely to lead to obesity.

A comparison between electroencephalography and somatosensory evoked potentials for outcome prediction following severe head injury.

The value of somatosensory evoked potentials (SEPs) for the prediction of outcome following severe head injury (HI) is established. The role of the electroencephalogram (EEG) in this setting is uncertain. In this comparative study, SEPs and EEGs were recorded within 3 days of severe HI in 90 patients, and the results related to outcome at 6 months. Patients with an isoelectric EEG or an EEG with repeated isoelectric intervals died. Reactivity of the EEG to external stimulation tended to be associated with favorable outcome. Grading of the EEGs on the basis of frequency composition otherwise provided no prognostic information. The presence of SEP scalp potentials bilaterally predicted favorable outcome, particularly if the central conduction times were normal. Conversely, the absence of one of both scalp potentials was associated with unfavorable outcome. EEGs thus provided useful prognostic information in only a minority of patients. By comparison, SEPs allowed prediction of both favorable and unfavorable outcomes in a much larger number of patients, and were therefore prognostically superior.

Early prediction of outcome from cerebral trauma by somatosensory evoked potentials.

The prognostic value of short-latency somatosensory evoked potentials (SEP) during the first 4 days after severe head injury was studied in a group of 100 ICU patients. There was a strong association between the presence of bilateral cortical potentials and a good recovery or moderate disability 6 months after injury. In contrast, the bilateral or unilateral absence of cortical potential was associated with severe disability, persistent vegetative state, or death in a high percentage of patients. A reliable prediction of outcomes was obtained from SEP recorded within 24 h of head injury. Predictive accuracy was not influenced by the time of recording or cumulative analysis of consecutive daily SEP over the first 4 days after injury. Short-latency SEP can provide a reliable and accurate prognosis for sedated and curarized patients, and can have an important role in the management and triage of patients with severe head injury who are undergoing intensive therapy.

Uvulopalatopharyngoplasty in severe idiopathic obstructive sleep apnoea syndrome.

Eleven patients with severe obstructive sleep apnoea syndrome, which was fully reversed by treatment with nasal continuous positive airways pressure, underwent uvulopalatopharyngoplasty. All patients were followed for at least 12 months after surgery. One patient with large tonsils was cured. Of the remaining 10 patients, two showed minimal objective improvement at 12 months and the rest were unchanged. Four patients subsequently developed cardiac failure due to obstructive sleep apnoea. Thus uvulopalatopharyngoplasty was not effective in these patients with severe idiopathic obstructive sleep apnoea syndrome.

The assessment of severe head injury by short-latency somatosensory and brain-stem auditory evoked potentials.

The relative prognostic value of short-latency somatosensory evoked potentials (SEPs) and brain-stem auditory evoked potentials (BAEPs) was assessed in 35 patients with post-traumatic coma. Analysis of the evoked potentials was restricted to those recorded within the first 4 days following head injury. Abnormal SEPs were defined as an increase in central somatosensory conduction time or an absence of the initial cortical potential following stimulation of either median nerve. Abnormal BAEPs were classified as an increase in the wave I-V interval or the loss of any or all of its 3 most stable components (waves I, III and V) following stimulation of either ear. SEPs reliably predicted both good and bad outcomes. All 17 patients in whom SEPs were graded as normal had a favourable outcome and 15 of 18 patients in whom SEPs were abnormal had an unfavourable outcome. Although abnormal BAEPs were associated with an unfavourable outcome in almost all patients (6 of 7), only 19 of 28 patients with normal BAEPs had a favourable outcome. The finding of normal BAEPs was therefore of little prognostic significance. These results confirm the superiority and greater sensitivity of the SEP in detecting abnormalities of brain function shortly after severe head trauma.

Obstructive sleep apnoea in Auckland: diagnosis and treatment.

In 1982 facilities for investigation of patients with sleep disorders were established at Auckland Hospital on a trial basis. Twenty patients with the obstructive sleep apnoea syndrome had been investigated and treated by the end of 1983. All were advised to avoid alcohol and sedatives and the obese patients were encouraged to lose weight. In the more severely affected patients either nasal continuous positive airway pressure or tracheostomy was used. The method of diagnosis and treatment are discussed.

Severe obstructive sleep apnoea treated with long term nasal continuous positive airway pressure.

Seven patients with the severe obstructive sleep apnoea syndrome were treated with nasal continuous positive airway pressure for from three to 22 months. This treatment reversed all symptoms due to the syndrome in every patient and continued to be used in five patients. One patient stopped treatment after eight months and subsequently remained incapacitated and another underwent tracheostomy at the time of transphenoidal hypophysectomy. Nasal continuous positive airway pressure is a safe, non-invasive treatment, which may be used in the presence of cardiac and respiratory failure. It is able fully to reverse upper airway obstruction and can be used at home on a long term basis.

The effect of experimental concussion on somatosensory evoked potentials.

Cortical somatosensory evoked potentials (SEPs) were recorded following experimental acceleration concussion in the rat. Immediately after head injury there was a general reduction in the amplitude of the SEP, and all its components were either temporarily abolished or increased in latency. The early components of the SEP recovered much more rapidly than did the amplitude and latencies of the later potentials. The purpose of the study was to investigate the relative effects of concussion on the lemniscal system (whose activity is reflected by the discrete early components of the SEP) and the reticular activating system (whose activity is reflected by the diffuse high amplitude late component of the SEP). Contrary to a widely accepted theory, there was a delay in transmission of somatosensory information through the lemniscal pathways as well as through the reticular system following head injury. Such an observation is consistent with recent studies of SEPs recorded from humans comatose after head trauma. As the changes in the morphology of the waveform of the SEP following concussion can be simulated by simply recording evoked potentials at high rates of stimulation, this suggests that the delays are caused by a failure or malfunction of synaptic transmission, but the level at which this is occurring remains to be determined.

Monitoring by compressed spectral array in prolonged coma.

Compressed spectral array (CSA) transforms the electroencephalogram into a succinct graphic display of changes in frequency and amplitude. We used CSA to monitor 51 comatose patients for at least 15 hours daily for up to 49 days. The crucial CSA feature was the presence or absence of a peak of activity within the theta or alpha frequency range (4.0 to 13 Hz). Persistence or return of this peak in the first 10 days of coma was seen in all patients who made a good recovery; continued absence of the peak for 10 days, or its return and loss, was associated with death or a residual disability.

Central somatosensory conduction time from 10 to 79 years.

Somatosensory evoked potentials were recorded simultaneously from the neck and scalp following stimulation of the median nerve at the wrist in 83 normal subjects aged 10-79 years. The central somatosensory conduction time was measured by subtracting the peak latency of the major response from the upper cervical area (N14) from that of the primary cortical response (N20). The central conduction time remained constant between 10 and 49 years but increased abruptly by approximately 0.3 msec between the fifth and sixth decades. Following this increase there was no further change in the central conduction time. Changes with age in the amplitude of N14 and N20 differed both from the changes in latency and from each other. The amplitude of N14 was stable between 10 and 39 years but then declined progressively. The amplitude of N20 deceased between 10 and 39 years and then increased until the end of the seventh decade.

Central somatosensory conduction after head injury.

In 94 patients with head injuries, conduction between the lower brainstem and the cerebral cortex was studied by recording evoked potentials from the scalp and neck following stimulation of the median nerves. A conduction time 3 SD or more above the normal mean (5.74 +/- 0.46 msec) or the absence of an evoked potential over one or both hemispheres was considered abnormal. During successive periods in the first 35 days after injury, the evoked potentials correlated with the outcome (classified as good or not good) in 75 to 84% of patients. Within 3 1/2 days the outcome was correctly predicted in 38 of 49 patients (78%). Six of the 7 surviving patients with persistent asymmetries of the cerebral evoked potentials remained hemiplegic. Serial studies over one year showed that both conduction time and amplitude recovered exponentially over many months, but differences persisted between the patients who made a good recovery and those who remained disabled.

The effect of pentobarbital on central somatosensory conduction time in the rat.

Somatosensory evoked potentials (SEPs) were recorded from skull electrodes in the rat. Central somatosensory conduction time was estimated by subtracting the peak latency of component II which is generated from the dorsal column nuclei and medial lemniscus from that of the primary cortical response. The mean was 2.67 +/- 0.10 msec during light pentobarbital anaesthesia. SEPs recorded during moderate anaesthesia showed delays of nearly 1 msec in anterior component III from the thalamus and sensory radiation, and the subsequent cortical potentials.

Age-dependent changes in the latency of the pattern visual evoked potential.

Pattern visual evoked potentials were recorded from 71 normal subjects aged 16-72 years, using a range of 5 luminance levels. At lower levels the latency increased after the fourth decade, while there was little age-dependent increase in latency at higher levels.

Central somatosensory conduction time in comatose patients.

Somatosensory conduction time between the dorsal column nuclei and the cerebral cortex may be measured following median nerve stimulation by recording evoked potentials from both scalp and neck. Central conduction times were significantly increased relative to normal (5.6 +/ 0.5 msec) in 11 of 24 comatose patients. Results within 10 and 35 days of onset of coma were correlated with the final clinical outcome. Conduction times were independent of serum phenobarbital (0 to 630 mumol per liter) and of central body temperature (35.0 to 38.5 degrees C). Serial studies in coma demonstrated (1) short-term increases during temporary metabolic disorders, and (2) sustained increases with gradual recovery over many months, particularly after head injury.