Jo Spong

Neuropsychological sequelae of digital mobile phone exposure in humans.

The effect of electromagnetic fields from digital mobile phones (DMP) on cognitive functioning is an area receiving increased attention. This study compares the performance of 120 volunteers on 8 neuropsychological tests during real or sham exposure to a DMP set to maximum permissible radiofrequency power output. When results were adjusted for known covariates (gender, age, or education), several alterations at significance levels of p<0.05 were obtained. Of these, simple and choice reaction times (CRT) showed strong evidence of impairment. Further, performance on the Trail Making Task (TMT) improved, supporting the hypothesis that DMP radiofrequency emissions improve the speed of processing of information held in working memory.

The effect of 90 day administration of a high dose vitamin B‐complex on work stress

Occupational stress is increasing in Western societies and the impact is significant at a personal, organisational and community level. The present study examined for the first time the efficacy of 3 months administration of two forms of high dose vitamin B complex on mood and psychological strain associated with chronic work stress.

Relationships Between Objective Sleep Indices and Symptoms in a Community Sample of People With Tetraplegia

OBJECTIVE To examine the relationships between injury severity, quality of life, sleep symptoms, objectively measured sleep, and sleep disorders in chronic tetraplegia. DESIGN Cross-sectional survey. SETTING Community. PARTICIPANTS People with tetraplegia (N=78; 59 men, 35 with motor and sensory complete tetraplegia; mean age ± SD, 43±12.1; age range 18-70y), living in the state of Victoria, Australia, who were not currently being treated for sleep disorders and who completed both questionnaires and sleep studies comprised the study cohort. INTERVENTION Questionnaire battery mailed to potential participants. Returned questionnaires were followed with full, home-based polysomnography. MAIN OUTCOME MEASURES Demographics and questionnaire responses. RESULTS Quality of life (Assessment of Quality of Life instrument) was worse in the group with complete lesions compared with incomplete lesions (P=.001; median=16; interquartile range, 9 vs 12 [12]), and the Apnea-Hypopnea Index was higher (P=.002; interquartile range, 32.0 [25.2] vs 13.2 [24.8]). Ninety-one percent of those with complete lesions had obstructive sleep apnea (Apnea-Hypopnea Index >10) versus 55.8% of those with incomplete tetraplegia. No effect of lesion level on the Apnea-Hypopnea Index was observed (r=-.04, P=.73). In the complete group, the time taken from sleep onset until the first rapid eye movement sleep period was significantly delayed at over 2 hours. Multiple regression analyses showed substantially stronger relationships between daytime sleep complaints and abnormalities observed in the sleep study in those with complete lesions. CONCLUSIONS Obstructive sleep apnea is a major problem, particularly in those with complete tetraplegia, and this single comorbidity is associated with reduced quality of life. In those with incomplete cervical lesions, the relationships between sleepiness, other sleep symptoms, and polysomnography indices are less precise.

Transcutaneous Measurement of Carbon Dioxide Tension During Extended Monitoring: Evaluation of Accuracy and Stability, and an Algorithm for Correcting Calibration Drift

BACKGROUND: When polysomnography is indicated in a patient with a presumed sleep disorder, continuous monitoring of arterial carbon dioxide tension (PaCO2) is desirable, especially if nocturnal hypoventilation is suspected. Transcutaneous CO2 monitors (PtcCO2) provide a noninvasive correlate of PaCO2, but their accuracy and stability over extended monitoring have been considered inadequate for the diagnosis of hypoventilation. We examined the stability and accuracy of PtcCO2 measurements and the performance of a previously described linear interpolation technique designed to correct for calibration drift. METHODS: We compared the PtcCO2 values from 2 TINA TCM-3 monitors to PaCO2 values from arterial blood samples obtained at the beginning, every 15 min of the first hour, and then hourly over 8 hours of monitoring in 6 hemodynamically stable, male, intensive care patients (mean age 46 ± 17 y). RESULTS: Time had a significant (P = .002) linear effect on the PtcCO2-PaCO2 difference, suggesting calibration drift over the monitoring period. We found no differences between monitor type or interaction between time and monitor type. For the 2 monitors the uncorrected bias was 3.6 mm Hg and the limits of agreement were −5.1 to 12.3 mm Hg. Our linear interpolation algorithm improved the bias and limits of agreement to 0.4 and −5.5 to 6.4 mm Hg, respectively. CONCLUSIONS: Following stabilization and correction for both offset and drift, PtcCO2 tracks PaCO2 with minimal residual bias over 8 hours of monitoring. Should future research confirm these findings, then interpolated PtcCO2 may have an increased role in detecting sleep hypoventilation and assessing the efficacy of treatment.

The feasibility of using auto-titrating continuous positive airway pressure to treat obstructive sleep apnoea after acute tetraplegia

Study design:A prospective cohort with acute tetraplegia.Objectives:Obstructive sleep apnoea (OSA) is common within weeks of tetraplegia. This study aimed at determining the feasibility of auto-titrating continuous positive airway pressure (CPAP) to treat OSA after acute tetraplegia.Setting:The Victorian Spinal Cord Service, Melbourne, AustraliaMethods:Participants underwent full, portable polysomnography. Those with an apnoea hypopnoea index of more than 10 events per hour were defined as having OSA and were offered treatment with CPAP. Treatment adherence was objectively monitored, and measures of quality of life, sleepiness and functional outcomes were determined at enrolment and 3 months later at study conclusion.Results:A total of 44 patients were admitted to our Spinal Cord Service over 9 months, and 19 participated. Fourteen of them had OSA and seven were adherent with therapy for 3 months. Compared with those who did not have OSA, and with those with OSA who were not adherent with CPAP, those who adhered to CPAP were older (mean (s.d.) age 54 years (13) versus non-adherent 28 years (15) and no OSA 29 years (10)) and heavier (body mass index (BMI) 32.5 (11.7), 24.1 (3.7) and 20.6 (3.1), respectively). CPAP-adherant patients and those without OSA showed a 50% or greater improvement in their state sleepiness over the 3 months. Patients with OSA who did not tolerate CPAP had no improvement in sleepiness.Conclusion:Auto-titrating CPAP is a feasible treatment for OSA in acute tetraplegia. Intensive clinical support was required initially, and a tolerance of therapy for at least 4 h for one of the first 3 days was predictive of good CPAP usage.Sponsorship:Transport Accident Commission.

Neuropsychological function in patients with acute tetraplegia and sleep disordered breathing

&NA; Sleep disordered breathing is highly prevalent following spinal cord injury and likely caused by the injury. Beyond the devastating physical consequences of spinal cord injury, neuropsychological dysfunction is also common. In both the able‐bodied and chronic spinal cord injury patients, sleep disordered breathing impairs many areas of neuropsychological function. However, this has not been investigated in patients with acute injury. Study objectives: To investigate the relationship between apnea severity and neuropsychological function in patients with acute‐onset tetraplegia and sleep disordered breathing. Methods: Polysomnography and neuropsychological testing were performed on 104 participants (age M = 45.60, SD = 16.38; 10 female) across 11 international sites, 2 months postinjury (M = 60.70 days, SD = 39.48). Neuropsychological tests assessed attention, information processing, executive function, memory, learning, mood, and quality of life. Results: More severe sleep apnea was associated with poorer attention, information processing, and immediate recall. Deficits did not extend to memory. Higher preinjury intelligence and being younger reduced the associations with sleep disordered breathing; however, these protective factors were insufficient to counter the damage to attention, immediate recall, and information processing associated with sleep disordered breathing. Conclusions: These data suggest that new spinal cord injury may function as a model of “acute sleep apnea” and that more widespread sleep apnea‐related deficits, including memory, may only be seen with longer exposure to apnea. These findings have important implications for functioning and skill acquisition during rehabilitation and, as such, highlight the importance of sleep health following tetraplegia.

Auto-titrating continuous positive airway pressure treatment for obstructive sleep apnoea after acute quadriplegia (COSAQ): study protocol for a randomized controlled trial

BackgroundQuadriplegia is a severe, catastrophic injury that predominantly affects people early in life, resulting in lifelong physical disability. Obstructive sleep apnoea is a direct consequence of quadriplegia and is associated with neurocognitive deficits, sleepiness and reduced quality of life. The usual treatment for sleep apnoea is nasal continuous positive airway pressure (CPAP); however, this is poorly tolerated in quadriplegia. To encourage patients to use this therapy, we have to demonstrate that the benefits outweigh the inconvenience. We therefore propose a prospective, multinational randomized controlled trial of three months of CPAP for obstructive sleep apnoea after acute quadriplegia.Methods/designSpecialist spinal cord injury centres across Australia, New Zealand, the UK and Canada will recruit medically stable individuals who have sustained a (new) traumatic quadriplegia (complete or incomplete second cervical to first thoracic level lesions). Participants will be screened for obstructive sleep apnoea using full, portable sleep studies. Those with an apnoea hypopnoea index greater than 10 per hour will proceed to an initial three-night trial of CPAP. Those who can tolerate CPAP for at least 4 hours on at least one night of the initial trial will be randomized to either usual care or a 3-month period of auto-titrating CPAP. The primary hypothesis is that nocturnal CPAP will improve neuropsychological functioning more than usual care alone. The secondary hypothesis is that the magnitude of improvement of neuropsychological function will be predicted by the severity of baseline sleepiness measures, sleep fragmentation and sleep apnoea. Neuropsychological tests and full polysomnography will be performed at baseline and 3 months with interim measures of sleepiness and symptoms of autonomic dysfunction measured weekly. Spirometry will be performed monthly. Neuropsychological tests will be administered by blinded assessors. Recruitment commenced in July 2009.DiscussionThe results of this trial will demonstrate the effect of nocturnal CPAP treatment of obstructive sleep apnoea in acute quadriplegia. If CPAP can improve neurocognitive function after injury, it is likely that rehabilitation and subsequent community participation will be substantially improved for this group of predominantly young and severely physically disabled people.Trial registrationAustralian New Zealand Clinical Trial RegistryACTRN12605000799651

Subjective sleep disturbances and quality of life in chronic tetraplegia

Study design:This is a cross-sectional survey.Objectives:The objective of this study was to evaluate the subjective sleep disturbances and quality of life in chronic tetraplegia.Setting:This study was conducted in a community sample from Victoria, Australia.Methods:People with tetraplegia were mailed a survey battery including the following: demographic questions; Karolinska Sleepiness Scale (KSS); Basic Nordic Sleepiness Questionnaire; Functional Outcomes of Sleep Questionnaire (FOSQ); Multivariate Apnoea Prediction Index and Assessment of Quality of Life (AQoL) Questionnaire. Scores were compared with the best available normative data.Results:A total of 163 of 424 (38%) surveys were returned (77% male; 39% sensory and motor complete; mean age±s.d.=46±14 years; mean years since injury=11±8 years). The AQoL health utility score (0.31±0.29) was significantly lower than published population norms. FOSQ total (17.55±2.57) and KSS (3.93±2.27) scores were no different from the best available population data. People with tetraplegia reported worse sleep habits, symptoms and quality than a normal population, as indicated on 17 of 21 questions on the Basic Nordic Sleep Questionnaire. Multivariate analysis found that greater injury severity (coefficient (95% CI)=0.14 (0.10, 0.18)), increasing age (−0.004 (−0.008, −0.001)) and worse sleep symptoms (−0.005 (−0.009, −0.0003)) were all significantly associated with reduced quality of life.Conclusion:People with chronic tetraplegia experience more subjective sleep problems and worse quality of life than their able-bodied counterparts. Quality of life is related to injury severity, age and sleep symptoms. Treating the sleep disorders experienced by people living with tetraplegia has the potential to improve their health and well-being.

Sleep disruption in tetraplegia: a randomised, double-blind, placebo-controlled crossover trial of 3 mg melatonin

Study design:Randomised, double-blind, placebo-controlled crossover trial of melatonin supplementation to people with complete tetraplegia.Objectives:To investigate the effect that 3 mg melatonin supplementation has on objective and subjective sleep, quality of life and mood of people living with complete tetraplegia.Setting:Austin Hospital Sleep Laboratory and participants’ homes, Melbourne, Victoria, Australia.Methods:Two week run-in followed by 3 week nightly administration of 3 mg melatonin or placebo, 2-week washout and further 3 week administration of the opposite treatment. Four testing sessions were conducted; the last nights of the run-in, treatment and washout periods. Testing sessions involved recording full polysomnography, completing a questionnaire battery and collecting urine and blood samples. The questionnaires assessed mood, sleep symptoms and health-related quality of life, and the urine and plasma samples assayed 6-sulphatoxymelatonin (aMT6s) and melatonin levels, respectively. A sleep diary was completed throughout the study.Results:Eight participants (mean (s.d.): age 49.5 years (16), postinjury 16.9 years (7.1)) were recruited in which seven concluded the protocol. Endogenous-circulating melatonin was significantly higher (P⩽0.01) following melatonin (urine: 152.94 μg h−1 (74.51), plasma: 43 554.57 pM (33 527.11)) than placebo (urine: 0.86 μg h−1 (0.40), plasma: 152.06 pM (190.55)). Subjective sleep improved significantly following melatonin specifically for duration of sleep per night and psychological wellbeing. Objective sleep showed a significant increase in light sleep with melatonin, with all other sleep parameters being unchanged.Conclusion:These results suggest that increasing melatonin in people with complete tetraplegia is beneficial, especially for subjective sleep. Investigation of the pharmacokinetics of melatonin metabolism in this population is warranted.Sponsorship:This project is proudly supported by the Transport Accident Commission.

Light sensors for objective light measurement in ambulatory polysomnography

Ambulatory polysomnography (PSG) does not commonly include an objective measure of light to determine the time of lights off (Loff), and thus cannot be used to calculate important indices such as sleep onset latency and sleep efficiency. This study examined the technical specifications and appropriateness of a prototype light sensor (LS) for use in ambulatory Compumedics Somte PSG.Two studies were conducted. The first examined the light measurement characteristics of the LS when used with a portable PSG device, specifically recording trace range, linearity, sensitivity, and stability. This involved the LS being exposed to varying incandescent and fluorescent light levels in a light controlled room. Secondly, the LS was trialled in 24 home and 12 hospital ambulatory PSGs to investigate whether light levels in home and hospital settings were within the recording range of the LS, and to quantify the typical light intensity reduction at the time of Loff. A preliminary exploration of clinical utility was also conducted. Linearity between LS voltage and lux was demonstrated, and the LS trace was stable over 14 hours of recording. The observed maximum voltage output of the LS/PSG device was 250 mV, corresponding to a maximum recording range of 350 lux and 523 lux for incandescent and fluorescent light respectively. At the time of Loff, light levels were within the recording range of the LS, and on average dropped by 72 lux (9–245) in the home and 76 lux (4–348) in the hospital setting. Results suggest that clinical utility was greatest in hospital settings where patients are less mobile. The LS was a simple and effective objective marker of light level in portable PSG, which can be used to identify Loff in ambulatory PSG. This allows measurement of additional sleep indices and support with clinical decisions.