Overall vigilance and sustained attention decrements in healthy aging

Age differences in sustained attention were investigated using a high-event rate digit-discrimination task at 6 levels of stimulus degradation (lasting 8.1 min each). Twenty-one young, 21 middle-aged, and 20 old healthy subjects were studied. Overall sensitivity (d') was equivalent in all groups. Although all subjects showed a sensitivity decrement over blocks, there were no age-related differences in sustained attention capacity. All subjects had larger decrements in d' over blocks at higher degradation levels. However, the performance decrement at higher degradation levels was equivalent in all groups, indicating similar decrement rates in sensitivity with increasing demands on effortful processing. These results indicate that overall levels of vigilance and the ability to sustain attention over time are equivalent in all groups under conditions requiring both automatic (low-degradation) and effortful (high-degradation) stimulus processing.     

The abbreviated vigilance task and cerebral hemodynamics

Transcranial Doppler sonography (TCD) and transcranial cerebral oximetry (TCCO) measures of cerebral blood flow velocity and oxygenation levels were collected during an abbreviated 12-min vigilance task. Both the TCD and TCCO measures showed higher levels of cerebral vascular activity in the right than in the left cerebral hemisphere; the cerebral laterality of vigilance occurs in an abbreviated task. Although there was a significant decline in performance over time, there was no significant change in the physiological measures over time during the abbreviated vigil. This latter finding does not match the physiological changes detected in long-duration vigils.     

Electronic Versus Paper Questionnaires: A Further Comparison in Persons with Asthma

The use of electronic data capture (EDC) to assess health-related quality of life (HRQOL) using validated questionnaires is increasing; however, it must be determined how data collected electronically correlate with the original mode of administration used in validation. Our objective was to compare paper and electronic administration of the standardized Asthma Quality of Life Questionnaire (AQLQ(S)), Pediatric Asthma Quality of Life Questionnaire (PAQLQ(S)), and Pediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ). Using a crossover design, adults and children with asthma and caregivers of children with asthma were recruited from clinics. Subjects were asked to complete both forms of the appropriate HRQOL measures at enrollment and 24-48 hours later. In addition, 30 subjects from each group were asked to participate in a 1-week reproducibility assessment of the electronic versions of the three questionnaires. Psychometric properties were assessed for each of the EDC versions. Intraclass correlation coefficients (ICC) and Pearson correlations were calculated to compare EDC and paper versions. A total of 51 adults (mean age 37, 73% females), 52 children (mean age 13, 38% females), and 51 caregivers (mean age 43, 92% females) were evaluated. Internal consistency (Cronbach's alpha) for the overall score of each questionnaire was: 0.96 for the AQLQ(S) and the PAQLQ(S), and 0.92 for the PACQLQ. Overall ICCs comparing paper with EDC were: 0.96 for the AQLQ(S), 0.91 for the PAQLQ(S), and 0.82 for the PACQLQ. Pearson's correlations were identical. One-week reproducibility (ICC) of the EDC versions was: 0.88 for the AQLQ(S), 0.78 for the PAQLQ(S), and 0.85 for the PACQLQ. When asked which method subjects preferred, the electronic version was chosen by 69% of adults, 77% of children, and 73% of caregivers. Additionally, 14% of adults, 14% of children, and 18% of caregivers reported no difference in preference. As in previous studies comparing electronic with paper questionnaires, this study revealed statistical evidence to support the use of EDC of the AQLQ(S), PAQLQ(S), and PACQLQ for populations with asthma.     

Renal disease burden following liver transplantation

Significant chronic kidney disease (CKD) occurs following orthotopic liver transplant (OLT). Since CKD is associated with increased cardiovascular events, mortality, and hepatic allograft dysfunction, early recognition of CKD and implementation of changes may improve the long-term outcome. The purpose of this study was to determine the burden of renal disease following OLT. PATIENTS AND METHODS: We retrospectively reviewed our OLT recipients from 1997 until 2004. We calculated glomerular filtration rates (GFR) using the Modification of Diet in Renal Disease study (MDRD) method. The GFRs were further subdivided into pre-MELD and post-MELD eras. RESULTS: During the study period, we performed 407 OLTs. We censored data from living donor liver transplants (n = 14), combined liver-kidney transplants (n = 12), and from patients whom we did not have complete data for 6 months after transplant (n = 40). Mean MELD score at the time of transplant was 18 +/- 7 (mean +/- standard deviation). The mean GFR at 6 months following OLT was 63.7 +/- 30.2 mL/min per 1.73 m(2). Only 14% (n = 47) of our patients had normal renal function at 6 months, while 78% (n = 266) of our patients had mild to moderate risk for renal failure. Eight percent (n = 28) had stage 4 or 5 CKD. There were no differences between the pre-MELD and post-MELD GFRs. CONCLUSIONS: The burden of renal disease is significant in our patient population at 6 months posttransplantation. It may be important to introduce CKD management as early as 6 months after transplant to impact the outcomes of OLT recipients.     

Alcohol intoxication reduces visual sustained attention

Effects of alcohol intoxication on visual sustained attention were studied using a vigilance task entailing detection of degraded target stimuli. Data were obtained in separate sessions under four ethanol doses, ranging from 0 (placebo) to 1.05 g/kg lean body weight, with periodic maintenance dosing of 0.12 g/kg. Intoxication lowered the overall level of detection performance, and in addition produced dose-related increases in the rate of performance decrement over time. Analysis of performance data using techniques derived from Signal Detection Theory indicated that the decrements were due specifically to alterations in perceptual sensitivity. Examination of eye movements and blinks indicated that the effects of ethanol were not mediated peripherally. Rather, alcohol appears to have deleterious effects on central processing capacity and the availability of capacity over time. The alcohol-related failure of sustained attention may contribute to increased accident risk in tasks requiring continuous performance.     

Auditory Evoked Potentials and Divided Attention

In a multi-channel divided attention task, 8 subjects listened to a sequence of tones delivered at one of two stimulation rates and at one of three spatial locations (channels): left ear, right ear, and an apparent position midway between left and right ears. Subjects were instructed to monitor one, two, or all three channels and detect slightly louder target tones in the monitored channel(s). Seven listening conditions were used, three in which subjects monitored one channel and ignored the others, another three in which two channels were simultaneously monitored and the third ignored, and a further condition in which all three channels were monitored. With a high stimulation rate, the N1 component of the vertex evoked potential (latency 70–130 msec) in both attended and unattended channels significantly decreased in amplitude with an increase in the number of monitored channels. At the same time, N1 was significantly larger when a channel was attended than when it was ignored. There were no significant effects under slow stimulation rate conditions. Like N1, target detectability (d') declined with increasing monitoring load only with a fast stimulation rate, but the correspondence between these two measures was not upheld in every condition. The results indicate that with a high “information load” in a multi-channel task, selective attention increases the vertex response in all attended channels, while divided attention decreases the response in both attended and unattended channels, thus suggesting that the N1 component of the auditory evoked potential reflects the apparent division of attentional capacity among competing auditory inputs.     

Onset of effect of budesonide and formoterol administered via one pressurized metered-dose inhaler in patients with asthma previously treated with inhaled corticosteroids

BACKGROUND: Onset of bronchodilation of budesonide/formoterol in one pressurized metered-dose inhaler (pMDI) has not been evaluated in asthma. OBJECTIVE: To evaluate time to onset of clinically significant bronchodilation (> or = 15% improvement in forced expiratory volume in 1 second) and patient-perceived onset of effect (OE) in patients previously receiving inhaled corticosteroids. METHODS: In two 12-week studies, patients 12 years and older with moderate to severe (study 1; n = 596) and mild to moderate (study 2; n = 480) persistent asthma received budesonide/formoterol pMDI, budesonide pMDI plus formoterol dry powder inhaler (study 1 only), budesonide pMDI, formoterol dry powder inhaler, or placebo. Postdose time to 15% or greater improvement in forced expiratory volume in 1 second and patient-perceived OE (assessed in a subset of patients 18 years and older [study 1, n=553; study 2, n=405]) were evaluated [corrected] RESULTS: More budesonide/formoterol-treated patients achieved onset of clinically significant bronchodilation within 15 minutes (median, 13 minutes) of administration at randomization vs those taking budesonide or placebo (P < .001). More patients receiving budesonide/formoterol vs budesonide and placebo reported feeling their study medication begin to work right away (P < or = .004; end of week 1). Similar results (P < .001) were observed for patient satisfaction with how quickly they felt their medication begin to work (except budesonide/formoterol vs budesonide, study 1 [P = .073]). Time to onset of clinically significant bronchodilation and patient-perceived OE of budesonide/formoterol and formoterol were similar. CONCLUSION: Budesonide/formoterol demonstrated a more rapid onset of clinically significant bronchodilation and a greater percentage of patients who perceived their medication working right away vs budesonide or placebo.