Cognitive performance is preserved following rapid heat stress exposure in firefighters.

Subcortical ischemic damage occurs in 62% to 82% of patients who undergo transcatheter aortic valve implantation (TAVI), leaving clinicians and researchers with the difficult task of understanding the functional consequences of these often silent strokes.1 Furthermore, the patients for whom TAVI is the best option typically have additional age-associated systemic health complications, making it more difficult to determine the impact of such an injury on short- and long-term recovery. Repeat neurological examination, diffusion-weighted magnetic resonance imaging (DW-MRI), and neuropsychological assessment, as performed by Ghanem et al,2 in this issue of Circulation: Cardiovascular Interventions are certainly helpful. In 111 patients with TAVI, they report cerebral embolization in 64% of the imaged subjects but early cognitive decline was diagnosed in only 5.4%, and late cognitive decline occurred at an even lower rate. However, in considering these silent infarcts, we start by asking whether it is appropriate to prioritize overall cognition (the forest) over individual cognitive domains (the trees) when assessing the effects of DW-MRI–detected embolization, a phenomenon that is usually random throughout the subcortex, neurologically subclinical, and often complicated by many perisurgical and postsurgical factors. Article see p 615 In most studies on the perioperative neurological impact of TAVI, the strokes are small, randomly scattered, and generally supratentorial, lesion characteristics that are less likely to produce observable change on standard neurological examination.1 Neuropsychological assessment improves detection of subtle postoperative cognitive decline (POCD) but is constrained by the relative sensitivity of available behavioral and self-report measures to capture clinically meaningful pos tinterventional differences associated with TAVI embolization. Nevertheless, this intersection between measurement selection and sensitivity and the relatively random neuroanatomical pattern of TAVI embolization may help to clarify whether we should target the forest or the trees of post-TAVI cognitive and functional outcomes. Ghanem et al2 treated cognition as …

PurposeIncreases in metabolic heat production during exercise stimulate perceptions of thermal discomfort as core and skin temperatures, and skin wettedness increase. Thermal discomfort is the precursor to thermal behavior. Employing thermal behavior during exercise may reduce thermal discomfort by attenuating the rise in core temperature. However, this remains unknown. We tested the hypothesis that thermal behavior attenuates the rise in core temperature and alleviates thermal discomfort during exercise.MethodsTwelve healthy subjects (24 ± 3 y, 6 females) performed two trials in which they completed 60 min of recumbent cycling exercise at a fixed rate of metabolic heat production (217 ± 28 W/m2) in a 27 ± 0°C, 48 ± 6% relative humidity environment. In both trials subjects wore a water perfused suit top. In the control trial, 34 ± 0°C water circulated through the top during the trial (CON). The experimental trial allowed for thermal behavior (BEH) where subjects were instructed to maintain their upper body thermally comfortable throughout. In BEH, subjects thermally behaved by pressing a button to receive cool water (2 ± 1°C) through the water perfused suit top for 2 min, which was followed by a 1 min wash out period. Mean skin (10 site) and core (telemetry pill) temperatures, mean skin wettedness (8 site), skin blood flow (forearm, laser Doppler), and local sweat rate (ventilated capsule) were measured continually. Local sweat rate was measured under (on mid‐axillary line) and outside (on anterior thigh, n=7) of the water perfused suit top. Whole body thermal comfort was recorded every 10 min. Water perfused suit top temperature provided an index of thermal behavior. Data are presented as mean ± SD as the absolute change from the values acquired pre‐exercise.ResultsMetabolic heat production was not different between trials (P=0.44). The increase in core temperature was greater in BEH vs. CON at 50 and 60 min (both by +0.1 ± 0.3°C, P<0.01). Mean skin temperature was reduced in BEH vs. CON from 20 min (by −0.5 ± 0.7°C, P<0.01) onwards (P<0.01). Mean skin wettedness was greater in BEH vs. CON from 30 min (by +0.01 ± 0.03 a.u., P<0.01) onwards (P<0.01). Water perfused suit top temperature was reduced in BEH vs. CON from 10 min (by −5.6 ± 7.0°C, P<0.01) onwards (P<0.01). Mid‐axillary sweat rate was attenuated in BEH vs. CON from 10 min (by −0.1 ± 0.12 g/cm2/min) onwards (P<0.01), and thigh sweat rate was attenuated at min 20 (by: −0.1 ± 0.2 g/cm2/min) and 60 (by −0.2 ± 0.2 g/cm2/min). Forearm skin blood flow was not different between BEH and CON at any time (P=0.20). Increases in whole body thermal discomfort were attenuated in BEH vs. CON within the first 10 min (by −0.4 ± 0.4 a.u., P=0.04) onwards (P<0.01).ConclusionsEmploying thermal behavior that reduces mean skin temperature during exercise alleviates thermal discomfort despite exacerbating the rise in core temperature and skin wettedness. Reductions in sweat rate may contribute to the greater rise in core temperature when employing thermal behavior. These findings may question the role of skin wettedness in stimulating thermal behavior during exercise.Support or Funding InformationSupported by lululemon athletica inc.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

This study aimed to establish the applicability of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) in the Old Order Amish (OOA) and to assess the genetic contribution toward the RBANS total score and its cognitive domains using a large family-based sample of OOA. RBANS data were collected in 103 OOA individuals from Lancaster County, Pennsylvania, including 85 individuals without psychiatric illness and 18 individuals with current psychiatric diagnoses. The RBANS total score and all five cognitive domains of in nonpsychiatric OOA were within half a SD of the normative data of the general population. The RBANS total score was highly heritable (h=0.51, P=0.019). OOA with psychiatric diagnoses had a numerically lower RBANS total score and domain scores compared with the nonpsychiatric participants. The RBANS appears to be a suitable cognitive battery for the OOA population as measurements obtained from the OOA are comparable with normative data in the US population. The heritability estimated from the OOA is in line with heritabilities of other cognitive batteries estimated in other populations. These results support the use of RBANS in cognitive assessment, clinical care, and behavioral genetic studies of neuropsychological functioning in this population.

Research on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has suggested that it has somewhat limited sensitivity in the differentiation of patients with mild cognitive impairment (MCI) from patients with dementia and elderly patients with no neurologic or psychiatric diagnoses. This study sought to increase the diagnostic utility of the RBANS in differentiating between patients with Alzheimer's disease (AD), MCI, and no diagnosis (ND) with the addition of construct comparable neuropsychological test measures. Diagnostic utility was assessed by comparing patients diagnosed with MCI to patients diagnosed with AD as well as to the ND group. The following cognitive domains were investigated: short-term memory, retention and long-term memory, language, attention, visuoconstruction, and overall cognitive functioning. Stepwise logistic regressions found that in the comparisons between MCI and ND, the Step 2 addition of construct comparable neuropsychological measures provided a significant diagnostic increase in the short-term memory and overall cognitive functioning models. In the comparisons between MCI and AD, the Step 2 additions provided a significant diagnostic increase in the short-term memory, visuoconstruction, and overall cognitive functioning models. Results suggested that the inclusion of construct similar neuropsychological tests significantly increases the diagnostic accuracy of the RBANS when attempting to identify more subtle cognitive deficits inherent in MCI.

Using RBANS to characterize cognitive treatment response in autoimmune encephalopathy

This study assesses the effects of transfusion of autologous or allogeneic blood on cerebral and tissue oxygenation during spinal surgery. Packed red blood cell transfusions are indicated to improve oxygen delivery to tissues. There are limited data demonstrating changes in tissue oxygenation with blood administration. Tissue (deltoid) and cerebral oxygenation were monitored using near-infrared spectroscopy during spinal surgery in patients. As indicated, cell saver or allogeneic blood was administered. Tissue and cerebral oxygenation were recorded before and after transfusion. The study enrolled 50 patients, 33 of whom (17 males and 16 females) received allogeneic blood (n= 8) or autologous blood (n= 25). Patients ranged in age from 9 to 19 years (14.0 ± 2.3 years) and in weight from 16.8 to 122.7 kg (54.6 ± 25.7 kg). Tissue oxygenation increased from 83 ± 9 (pretransfusion) to 86 ± 7 at the end of transfusion (p= .002) and remained at the same level (86 ± 7) in the post-transfusion period. Cerebral oxygenation increased from 76 ± 8 (pretransfusion) to 84 ± 8 at the end of transfusion (p< .001) and remained at 84 ± 8 in the post-transfusion period. Changes in tissue and cerebral oxygenation were similar between cell saver and allogeneic blood and between starting hemoglobin value <8 gm/dL and starting hemoglobin ≥8 gm/dL. In conclusion, although both cerebral and tissue oxygenation increased during the administration of either allogeneic or autologous blood, the clinical impact was likely limited given the high initial tissue and cerebral oxygenation values. No differences were noted between autologous (cell saver) and allogeneic blood or based on the starting hemoglobin value.

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a brief, standardized neuropsychological test that assesses several areas of cognitive function. Recent studies, although sparse, have examined the use of the RBANS to detect cognitive deficits in individuals with manifest Huntington disease (HD); however, no studies have investigated its utility to detect cognitive deficits in individuals with premanifest HD (PreHD), where cognitive symptoms are thought to be more subtle. To assess cognitive deficits in individuals with HD, particularly in individuals with PreHD, using an easily administered, brief but comprehensive, neuropsychological test. We administered the RBANS to 31 individuals with HD, 29 individuals with PreHD, and 22 healthy controls (HC) at an academic HD clinical research center and collected RBANS Total, Index, and subtest scores for group comparisons. The HD group had significantly lower RBANS Total, Index, and subtest scores than the HC. The PreHD group had significantly lower RBANS Total scores and Coding subtest scores than the HC, but no other significant group differences were identified. Our results substantiate previous findings of significant impairment on the RBANS in individuals with HD. In addition, we are the first to demonstrate that, although the RBANS can identify deficits in psychomotor speed and information processing in individuals with PreHD, it does not appear to have the ability to detect impairment in any additional cognitive domains in individuals with PreHD.

Changes in cerebral oxygenation and hemodynamics during cranial ultrasound in preterm infants

ABSTRACTThe objective of this study was to determine whether administration of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) prior to other neuropsychological testing improves performance on subsequent measures due to practice effects. Participants completed the RBANS and related neuropsychological measures of the same cognitive domain in one of two counterbalanced orders. A MANOVA and follow-up independent t-tests were used to examine whether or not completing one set of measures prior to the other was associated with score differences. Prior administration of the RBANS did not impact performance on subsequent testing. However, a significant effect of test order administration was found such that the group administered the RBANS second performed worse on RBANS delayed memory measures. This finding was likely due to proactive interference, given that items from initially administered memory measures presented as intrusions on subsequently administered memory measures. Current results indicate that the practice of administering the RBANS as a screener prior to administration of additional tests will not impact performance on the subsequent tests. Although practice effects were not found, clinicians and researchers administering memory measures with similar designs (e.g., verbal list-learning tasks) within a single testing session should be aware of the potential of interference effects.

Aging negatively impacts cognitive function and physical function in older adults. Physical activity may protect or improve the brain and physical functions that are crucial for multiple health outcomes in older adults, whereas obesity may negatively impact these outcomes. PURPOSE: To examine the association between cognitive function with BMI and physical function in underactive older adults. METHODS: Baseline data were examined from sedentary older adults (N=31; age=70.3±3.7 years; BMI=28.8±4.6 kg/m2) prior to engaging in a 12-month physical activity intervention. Assessments included height, weight, physical function, and cognitive function. Cognitive function was assessed using the Modified Mini-Mental State (3MS) examination and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Physical function performance was assessed using the time to complete the 400-Meter Walk Test (minutes). RESULTS: Average time to complete the 400-meter walk was 6.3±1.0 minutes, which was modestly associated with BMI (r=0.312, p=0.088). The 3MS Total Score (94.7±3.7) was not significantly correlated with BMI (r=-.158; p=.397) or 400-Meter Walk Test performance (r=-.152; p=.415). Similarly, the RBANS Sum of Index Score (209.0±21.1) was not significantly correlated with BMI (r=-.297; p=.105) or 400-Meter Walk Test performance (r=-.164; p=.378). When examining this relationship by cognitive domain, a higher BMI was associated with a poorer RBANS Immediate Memory Index Score (r=-.412; p=.021). We also observed that worse performance on the 400-Meter Walk Test was associated with poorer RBANS Immediate Memory Index Score (r=-.314; p=.08). Neither BMI nor 400-Meter Walk performance were significantly associated with RBANS Visuospatial/Constructional Index, Language Index, Attention Index, or Delayed Memory Index scores. CONCLUSION: Findings reveal that RBANS Immediate Memory Index score was inversely associated with both BMI and physical function in sedentary older adults. This may suggest that both obesity and poor physical function negatively impact immediate memory performance in older adults. Future studies to investigate whether and how physical therapeutics may enhance short-term memory function in older adults are warranted. Supported by UPMC Enterprises

Neuropsychological assessment of older individuals with dementing illnesses has suffered from a lack of appropriately designed test instruments. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was developed for the dual purposes of identifying and characterizing abnormal cognitive decline in the older adult and as a neuropsychological screening battery for younger patients. The entire battery takes less than 30 minutes to administer, and yields scaled scores for five cognitive domains. The current study reports preliminary clinical validity results with the RBANS, comparing very mildly demented patients with a diagnosis of probable Alzheimer's disease (n = 20) to patients with Huntington's disease (n = 20) and normal controls (n = 40). Although the patient groups had essentially identical total scores on the RBANS, they exhibited opposite profiles, differing significantly on four of the five subsections. The AD patients performed most poorly on Language, and Delayed Memory subsections, while the HD patients obtained their lowest scaled scores on the Attention and the Visuospatial/Constructional subsections. These results are consistent with the neuropsychological profiles of these dementing disorders derived from lengthier standardized tests and experimental investigations. In addition, even those patients who performed above the suggested cut-off points on the MMSE and the Dementia Rating Scale scored significantly below their controls on the RBANS. These data suggest that the RBANS is effective at both detecting and characterizing dementia of different etiologies.

Effect of desflurane on changes in regional cerebral oxygenation in patients undergoing one-lung ventilation is equivalent to the effect of propofol

Alterations in brain activity and cerebral blood flow occur with increased hypothalamic temperatures. Recently, it has been demonstrated that motor unit activation and force output decrease as a result of having an elevated core temperature per se, independent of exercise and maximal cardiovascular strain. The mechanisms behind this hyperthermic fatigue are not well understood, although some researchers postulate that changes in cerebral function play a role. PURPOSE To investigate whether changes in cerebral oxygenation influence the brain's ability to effectively recruit motor units and thus, sustain maximal isometric force output during passive hyperthermia. METHODS Five healthy males (age 22 ± 3 yrs: mean ± SD) were seated on a kneeextensor myograph in an environmental chamber (∼35°C) and their core temperature (Tre) was monitored via a rectal thermistor. A Near-Infrared Spectroscopy (NIRS) probe was placed over the left frontal lobe of the forehead and a liquid conditioning garment was worn in which 50°C water was circulated over the skin to passively increase core temperature. With every 0.5°C increase in Tre from baseline (∼37°C) to 39.0°C, muscle function was assessed via an isometric 10 s maximum voluntary contraction (MVC) of the knee extensors, and the interpolated-twitch technique was used to estimate motor unit activation (MUA). Subjects were then cooled (8°C water) and repeated the contraction protocol for every Tre decrease of 0.5°C until the ∼37°C baseline was reached. RESULTS Cardiovascular strain was moderate, with heart rate increasing (P<0.05) from 80 ± 13 to 139 ± 32 bpm at 39.0°C, before decreasing with cooling (75 ± 15 bpm). Mean arterial pressure decreased during heating from 94 ± 3 to 79 ± 5 mmHg before returning to 96 ± 9 mmHg. Force output decreased from 553 ± 133 at Tre 37°C to 430 ± 176 N at Tre of 39.0°C and remained depressed (474 ± 111 N) with cooling. MUA was attenuated in heat (from 90 ± 5 to 84 ± 6%) before returning to 91 ± 5 %. Cerebral oxygenation (cOX) levels during MVC did not differ significantly throughout passive heating. Cooling increased MVC cOX from −16.3 ± 5.2 μM to −6.7 ± 9.4 μM although cooling baseline measures remained depressed compared to the start of the protocol (4.0 ± 3.8 μM). CONCLUSIONS Although the magnitude of cerebral oxygenation changes throughout the cooling protocol, these changes do not coincide with decreases observed in MAP, force output or MUA with increased core temperature. Supported by an NSERC Discovery Grant.

Near infrared spectroscopy (NIRS) is emerging as a promising method of assessing individualised cerebral oxygenation responses to red blood cell (RBC) transfusion. However, the impact of liberal (high) versus restrictive (low) haemoglobin thresholds on transfusion-related changes in cerebral tissue oxygenation (crSO2) remains unclear. This meta-analysis compares cerebral oxygenation changes in preterm neonates following transfusion with liberal compared to restrictive haemoglobin thresholds. Data was extracted (PubMed/Medline, Embase, Web of Science, and Cochrane Database of Systematic Reviews) and risk of bias and certainty of evidence reviewed. Included studies reported changes in cerebral oxygenation in preterm infants receiving RBCs in response to reaching either a liberal or restrictive transfusion threshold. A random-effects model was used to determine effect size and 95% confidence for the primary outcome of change in crSO2. Forty-three full text articles were assessed for eligibility with seven studies included for meta-analysis (restrictive threshold: n=357, liberal threshold: n=220). crSO2 increased following transfusion in both the restrictive (6.40% 95% CI [3.85, 8.95], p<0.001) and liberal (2.75% 95% CI [0.35, 5.14], p=0.03) groups. However, the magnitude of change was greater for those transfused at a restrictive threshold (Q=4.19, df=1, p=0.04). The restrictive group also demonstrated a greater transfusion-related decrease in cerebral fractional oxygen extraction than the liberal group (Q=8.30, df=1, p<0.001). Greater improvements to cerebral oxygenation occurred in preterm neonates with a restrictive threshold, suggesting enhanced physiological benefit in response to transfusion. However, meaningful clinical conclusions are limited due to low certainty of evidence and considerable inconsistencies across reporting.

PURPOSE: To determine if fatigue at maximal aerobic power output was associated with a critical level of cerebral oxygenation, thirteen male cyclists performed incremental exercise tests (25 W·min−1 ramp) under normoxic (NORM: 21% FIO2) and acute hypoxic (HYPOX: 12% FIO2) conditions. METHODS: Near infrared spectroscopy (NIRS) was used to assess changes in cerebral and muscle oxygenation during incremental exercise. Concentration (μM) changes in oxy- and deoxy-hemoglobin (ΔO2Hb, Δ HHb) in the left vastus lateralis and frontal cortex (Oxymon, Artinis, The Netherlands) were measured and used to calculate an index of change in tissue oxygenation (ΔHbdiff = ΔO2Hb - ΔHHb). Repeated measures ANOVA analyses were performed across treatments and relative workrates (α = 0.05). RESULTS: During NORM, cerebral oxygenation (ΔHbdiff) was maintained up to 75% peak power output (Powerpeak), but decreased thereafter. Muscle oxygenation (ΔHbdiff) progressively decreased up to 75% Powerpeak, but was unchanged thereafter. During HYPOX cerebral oxygenation progressively decreased across all workrates, while muscle oxygenation again decreased up to 75% Powerpeak and remained unchanged thereafter. The magnitudes of changes were greater in HYPOX than NORM for cerebral but not muscle ΔHbdiff at 100% Powerpeak. CONCLUSION: These results demonstrate a large tolerance for changes in cerebral oxygenation at maximal aerobic power output and do not support the notion that a critical level of frontal cortex oxygenation limits exercise in NORM.Figure