1
|
Beer J, Mojica AJ, Blacker KJ, Dart TS, Morse BG, Sherman PM. Relative Severity of Human Performance Decrements Recorded in Rapid vs. Gradual Decompression. Aerosp Med Hum Perform 2024; 95:353-366. [PMID: 38915160 DOI: 10.3357/amhp.6402.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
INTRODUCTION: Cabin decompression presents a threat in high-altitude-capable aircraft. A chamber study was performed to compare effects of rapid (RD) vs. gradual decompression and gauge impairment at altitude with and without hypoxia, as well as to assess recovery.METHODS: There were 12 participants who completed RD (1 s) and Gradual (3 min 12 s) ascents from 2743-7620 m (9000-25000 ft) altitude pressures while breathing air or 100% O₂. Physiological indices included oxygen saturation (SPo₂), heart rate (HR), respiration, end tidal O₂ and CO₂ partial pressures, and electroencephalography (EEG). Cognition was evaluated using SYNWIN, which combines memory, arithmetic, visual, and auditory tasks. The study incorporated ascent rate (RD, gradual), breathing gas (air, 100% O₂) and epoch (ground-level, pre-breathe, ascent-altitude, recovery) as factors.RESULTS: Physiological effects in hypoxic "air" ascents included decreased SPo₂ and end tidal O₂ and CO₂ partial pressures (hypocapnia), with elevated HR and minute ventilation (V˙E); SPo₂ and HR effects were greater after RD (-7.3% lower and +10.0 bpm higher, respectively). HR and V˙E decreased during recovery. SYNWIN performance declined during ascent in air, with key metrics, including composite score, falling further (-75% vs. -50%) after RD. Broad cognitive impairment was not recorded on 100% O₂, nor in recovery. EEG signals showed increased slow-wave activity during hypoxia.DISCUSSION: In hypoxic exposures, RD impaired performance more than gradual ascent. Hypobaria did not comprehensively impair performance without hypoxia. Lingering impairment was not observed during recovery, but HR and V˙E metrics suggested compensatory slowing following altitude stress. Participants' cognitive strategy shifted as hypoxia progressed, with efficiency giving way to "satisficing," redistributing effort to easier tasks.Beer J, Mojica AJ, Blacker KJ, Dart TS, Morse BG, Sherman PM. Relative severity of human performance decrements recorded in rapid vs. gradual decompression. Aerosp Med Hum Perform. 2024; 95(7):353-366.
Collapse
|
2
|
Post TE, Heijn LG, Jordan J, van Gerven JMA. Sensitivity of cognitive function tests to acute hypoxia in healthy subjects: a systematic literature review. Front Physiol 2023; 14:1244279. [PMID: 37885803 PMCID: PMC10598721 DOI: 10.3389/fphys.2023.1244279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Abstract
Acute exposure to hypoxia can lead to cognitive impairment. Therefore, hypoxia may become a safety concern for occupational or recreational settings at altitude. Cognitive tests are used as a tool to assess the degree to which hypoxia affects cognitive performance. However, so many different cognitive tests are used that comparing studies is challenging. This structured literature evaluation provides an overview of the different cognitive tests used to assess the effects of acute hypoxia on cognitive performance in healthy volunteers. Less frequently used similar cognitive tests were clustered and classified into domains. Subsequently, the different cognitive test clusters were compared for sensitivity to different levels of oxygen saturation. A total of 38 articles complied with the selection criteria, covering 86 different cognitive tests. The tests and clusters showed that the most consistent effects of acute hypoxia were found with the Stroop test (where 42% of studies demonstrated significant abnormalities). The most sensitive clusters were auditory/verbal memory: delayed recognition (83%); evoked potentials (60%); visual/spatial delayed recognition (50%); and sustained attention (47%). Attention tasks were not particularly sensitive to acute hypoxia (impairments in 0%-47% of studies). A significant hypoxia level-response relationship was found for the Stroop test (p = 0.001), as well as three clusters in the executive domain: inhibition (p = 0.034), reasoning/association (p = 0.019), and working memory (p = 0.024). This relationship shows a higher test sensitivity at more severe levels of hypoxia, predominantly below 80% saturation. No significant influence of barometric pressure could be identified in the limited number of studies where this was varied. This review suggests that complex and executive functions are particularly sensitive to hypoxia. Moreover, this literature evaluation provides the first step towards standardization of cognitive testing, which is crucial for a better understanding of the effects of acute hypoxia on cognition.
Collapse
Affiliation(s)
- Titiaan E. Post
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
| | - Laurens G. Heijn
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
- Leiden Academic Centre for Drug Research, Leiden, Netherlands
| | - Jens Jordan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
- Medical Faculty, University of Cologne, Cologne, Germany
| | - Joop M. A. van Gerven
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
- Leiden University Medical Center, Leiden, Netherlands
- Central Committee on Research Involving Human Subjects (CCMO), The Hague, Netherlands
| |
Collapse
|
3
|
Wong NY, van Waart H, Sleigh JW, Mitchell SJ, Vrijdag XC. A systematic review of electroencephalography in acute cerebral hypoxia: clinical and diving implications. Diving Hyperb Med 2023; 53:268-280. [PMID: 37718302 PMCID: PMC10597603 DOI: 10.28920/dhm53.3.268-280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 07/27/2023] [Indexed: 09/19/2023]
Abstract
Introduction Hypoxia can cause central nervous system dysfunction and injury. Hypoxia is a particular risk during rebreather diving. Given its subtle symptom profile and its catastrophic consequences there is a need for reliable hypoxia monitoring. Electroencephalography (EEG) is being investigated as a real time monitor for multiple diving problems related to inspired gas, including hypoxia. Methods A systematic literature search identified articles investigating the relationship between EEG changes and acute cerebral hypoxia in healthy adults. Quality of clinical evidence was assessed using the Newcastle-Ottawa scale. Results Eighty-one studies were included for analysis. Only one study investigated divers. Twelve studies described quantitative EEG spectral power differences. Moderate hypoxia tended to result in increased alpha activity. With severe hypoxia, alpha activity decreased whilst delta and theta activities increased. However, since studies that utilised cognitive testing during the hypoxic exposure more frequently reported opposite results it appears cognitive processing might mask hypoxic EEG changes. Other analysis techniques (evoked potentials and electrical equivalents of dipole signals), demonstrated sustained regulation of autonomic responses despite worsening hypoxia. Other studies utilised quantitative EEG analysis techniques, (Bispectral index [BISTM], approximate entropy and Lempel-Ziv complexity). No change was reported in BISTM value, whilst an increase in approximate entropy and Lempel-Ziv complexity occurred with worsening hypoxia. Conclusions Electroencephalographic frequency patterns change in response to acute cerebral hypoxia. There is paucity of literature on the relationship between quantitative EEG analysis techniques and cerebral hypoxia. Because of the conflicting results in EEG power frequency analysis, future research needs to quantitatively define a hypoxia-EEG response curve, and how it is altered by concurrent cognitive task loading.
Collapse
Affiliation(s)
- Nicole Ye Wong
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
| | - Hanna van Waart
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Jamie W Sleigh
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
| | - Simon J Mitchell
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
- Slark Hyperbaric Unit, North Shore Hospital, Auckland, New Zealand
| | - Xavier Ce Vrijdag
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Corresponding author: Dr Xavier CE Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland 1142, New Zealand, ORiD: 0000-0001-5907-6083,
| |
Collapse
|
4
|
Masè M, Viziano A, Strapazzon G, Alessandrini M, Micarelli A. Auditory function in humans at high altitude. A scoping review. PLoS One 2023; 18:e0291919. [PMID: 37733697 PMCID: PMC10513325 DOI: 10.1371/journal.pone.0291919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/09/2023] [Indexed: 09/23/2023] Open
Abstract
PURPOSE High-altitude (HA) affects sensory organ response, but its effects on the inner ear are not fully understood. The present scoping review aimed to collect the available evidence about HA effects on the inner ear with focus on auditory function. METHODS The scoping review was conducted following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews. PubMed, Scopus, and Web of Science electronic databases were systematically searched to identify studies conducted in the last 20 years, which quantified in healthy subjects the effects of HA on auditory function. RESULTS The systematic search identified 17 studies on a total population of 888 subjects (88.7% male, age: 27.8 ± 4.1 years; median sample size of 15 subjects). Nine studies were conducted in a simulated environment and eight during real expeditions at HA. To quantify auditory function, six studies performed pure tone audiometry, four studies measured otoacoustic emissions (OAE) and eight studies measured auditory evoked responses (AER). Study protocols presented heterogeneity in the spatio-temporal patterns of HA exposure, with highly varying maximal altitudes and exposure durations. CONCLUSION Most studies reported a reduction of auditory function with HA in terms of either elevation of auditory thresholds, lengthening of AER latencies, reduction of distortion-product and transient-evoked OAEs. Future studies in larger populations, using standardized protocols and multi-technique auditory function evaluation, are needed to further characterize the spatio-temporal pattern of HA effects along the auditory pathways and clarify the pathophysiological implications and reversibility of the observed changes.
Collapse
Affiliation(s)
- Michela Masè
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology–CIBIO, University of Trento, Trento, Italy
| | - Andrea Viziano
- Department of Clinical Sciences and Translational Medicine, ENT Unit, University of Rome Tor Vergata, Rome, Italy
| | - Giacomo Strapazzon
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Marco Alessandrini
- Department of Clinical Sciences and Translational Medicine, ENT Unit, University of Rome Tor Vergata, Rome, Italy
| | - Alessandro Micarelli
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Unit of Neuroscience, Rehabilitation and Sensory Organs, UNITER ONLUS, Rome, Italy
| |
Collapse
|
5
|
Vento KA, Borden CK, Blacker KJ. Sex comparisons in physiological and cognitive performance during hypoxic challenge. Front Physiol 2022; 13:1062397. [PMID: 36505049 PMCID: PMC9727089 DOI: 10.3389/fphys.2022.1062397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/11/2022] [Indexed: 11/24/2022] Open
Abstract
Within the tactical aviation community, human performance research lags in considering potential psychophysiological differences between male and female aviators due to little inclusion of females during the design and development of aircraft systems. A poor understanding of how male and female aviators differ with respect to human performance results in unknown potential sex differences on aeromedically relevant environmental stressors, perchance leading to suboptimal performance, safety, and health guidelines. For example, previous hypoxia studies have excluded female participants or lacked a sizeable sample to examine sex comparisons. As such, progress toward sensor development and improving hypoxia familiarization training are stunted due to limited knowledge of how individual differences, including sex, may or may not underlie hypoxia symptoms and performance impairment. Investigating sex differences bridges the gap between aerospace medicine and operational health, and addressing hypoxia is one of many facets yet to be studied. In the current study, we retrospectively examined N = 6 hypoxia studies with male-female participant samples (total, N = 189; male, n = 118; female, n = 71). We explored sex as a predictor of physiological response, sensory deficits, the severity of cognitive performance declines, and symptom manifestation via linear and binary logistic regression models. We found that the female sex predicted lower peripheral oxygen saturation and the likelihood of headache reporting in response to hypoxic challenge, yet explained little variance when combined with age and body mass index. The sensory and cognitive performance models did not converge, suggesting high intra-individual variability. Together, sex, age, and body mass index were not the most robust predictors in responses to hypoxic challenge; we cannot infer this for sensory deficits and cognitive performance within an experimentally induced hypoxic environment. The findings have implications for improving hypoxia familiarization training, monitoring sensor development, and emergency response and recovery protocols in case of a hypoxia occurrence suitable for all aircrew. We recommend continuing to elucidate the impact of sex and intrapersonal differences in hypoxia and other aeromedically relevant stressors in tactical aviation.
Collapse
Affiliation(s)
- Kaila A. Vento
- Naval Medical Research Unit-Dayton Wright-Patterson Air Force Base, Dayton, OH, United States,Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Cammi K. Borden
- Naval Medical Research Unit-Dayton Wright-Patterson Air Force Base, Dayton, OH, United States,Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Kara J. Blacker
- Naval Medical Research Unit-Dayton Wright-Patterson Air Force Base, Dayton, OH, United States,*Correspondence: Kara J. Blacker,
| |
Collapse
|
6
|
Hohenauer E, Taube W, Freitag L, Clijsen R. Sex differences during a cold-stress test in normobaric and hypobaric hypoxia: A randomized controlled crossover study. Front Physiol 2022; 13:998665. [PMID: 36225301 PMCID: PMC9549379 DOI: 10.3389/fphys.2022.998665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/05/2022] [Indexed: 11/13/2022] Open
Abstract
Cold and hypoxia are two stressors that are frequently combined and investigated in the scientific literature. Despite the growing literature regarding normobaric hypoxia (NH) and hypobaric hypoxia (HH), responses between females and males are less often evaluated. Therefore, this study aims to investigate the physiological sex differences following a cold-stress test under normoxia, normobaric- and hypobaric hypoxia. A total of n = 10 females (24.8 ± 5.1 years) and n = 10 males (30.3 ± 6.3 years) from a university population volunteered for this study. The cold-stress test (CST) of the right hand (15°C for 2 min) was performed using a randomised crossover design in normobaric normoxia, NH and HH. The change (∆) from baseline to post-CST up to 15 min was analysed for cutaneous vascular conductance (CVC) and the hands’ skin temperature, whilst the mean values across time (post-CST up to 15 min) were assessed for peripheral oxygen saturation (SpO2), thermal sensation- and comfort. Pressure pain threshold (PPT) was assessed after the post-CST 15 min period. The hands’ skin temperature drop was higher (p = 0.01) in the female group (∆3.3 ± 1.5°C) compared to the male group (∆1.9 ± 0.9°C) only in NH. Females (−0.9 ± 0.5) rated this temperature drop in NH to feel significantly colder (p = 0.02) compared to the males (−0.2 ± 0.7). No differences were observed between sexes in NN, NH, and HH for ∆CVC, SpO2, thermal comfort and PPT. In conclusion, females and males show similar reactions after a CST under normoxia and hypoxia. Sex differences were observed in the local skin temperature response and thermal sensation only in NH.
Collapse
Affiliation(s)
- Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- Department of Physiotherapy, International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
- Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- *Correspondence: Erich Hohenauer,
| | - Wolfgang Taube
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Livia Freitag
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
| | - Ron Clijsen
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- Department of Physiotherapy, International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Health, Bern University of Applied Sciences, Berne, Switzerland
| |
Collapse
|
7
|
Blacker KJ, McHail DG. Effects of Acute Hypoxia on Early Visual and Auditory Evoked Potentials. Front Neurosci 2022; 16:846001. [PMID: 35546885 PMCID: PMC9082933 DOI: 10.3389/fnins.2022.846001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/31/2022] [Indexed: 11/28/2022] Open
Abstract
Reduced levels of environmental oxygen lead to hypoxic hypoxia and are a primary threat in tactical aviation. The visual system is particularly vulnerable to hypoxia, and its impairment can severely impact performance. The auditory system is relatively spared by hypoxia, although which stages of auditory processing are most impacted by hypoxia remains unclear. Previous work has used electroencephalography (EEG) to assess neural markers of cognitive processing for visual and auditory stimuli and found that these markers were sensitive to a normobaric hypoxic exposure. In the current study, we assessed whether early sensory evoked potentials, that precede cognitive activity, are also impaired by normobaric hypoxia. In a within-subjects design, we compared visual (P100) and auditory evoked potentials (sensory gating for the P50, N100, and P200) in 34 healthy adults during normoxic (21% O2) and two separate hypoxic (9.7% O2) exposures. Self-reported symptoms of hypoxia were also assessed using the Hypoxia Symptom Questionnaire (HSQ). We found that P100 mean amplitude was not reduced under hypoxic compared to normoxic conditions, suggesting no statistically significant impairment of early visual processing. The sensory gating ratio for auditory stimuli was intact for paired responses of the P50 and N100. However, the P200 sensory gating ratio was attenuated under hypoxic compared to normoxic conditions, suggesting disruption of the auditory system specific to the level of allocating attention that follows basic auditory processing. Exploratory analyses of HSQ scores identified a robust effect of hypoxia. However, consistency of symptoms reported between the two hypoxia exposures exhibited high intra-individual variability, which may have implications for the theory that individuals have a consistent hypoxia signature or reliable constellation of responses to hypoxia. These findings suggest that early sensory processing is not impaired during hypoxia, but for the auditory system there is impairment at the level of attentional processing. Given the previous findings of impaired visual performance under hypoxia, these results suggest that this impairment does not stem from early visual processing deficits in visual cortex. Together these findings help focus the search on when and where hypoxia-induced deficits occur and may guide the development of countermeasures for hypoxia in tactical aviation.
Collapse
Affiliation(s)
- Kara J Blacker
- Naval Medical Research Unit-Dayton, Wright-Patterson Air Force Base (AFB), Dayton, OH, United States
| | - Daniel G McHail
- Naval Medical Research Unit-Dayton, Wright-Patterson Air Force Base (AFB), Dayton, OH, United States
| |
Collapse
|
8
|
Blacker KJ, McHail DG. Time course of recovery from acute hypoxia exposure as measured by vigilance and event-related potentials. Physiol Behav 2021; 239:113508. [PMID: 34175363 DOI: 10.1016/j.physbeh.2021.113508] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/02/2021] [Accepted: 06/22/2021] [Indexed: 11/24/2022]
Abstract
Exposure to reduced levels of breathable oxygen is known to cause a number of deleterious effects on human performance. Previous work has demonstrated that in healthy adults, hypoxia results in decrements on a wide range of sensory, cognitive, and motor tasks. However, very little is known about the time course of recovery of cognitive functions following a hypoxic exposure. While previous studies have shown that physiological responses like heart rate and oxygen saturation rebound almost immediately, one previous study has shown a delayed recovery for response time (RT) measures following hypoxia. In the current study, we assessed the time course of neurocognitive recovery following a hypoxic exposure in healthy adults using the psychomotor vigilance task (PVT), passively elicited event-related potentials (ERPs) that assess auditory processing, and physiological measures. We also compared whether speed of recovery differed when participants were provided with 21% or 100% oxygen immediately following hypoxic exposure. Participants underwent a baseline testing session and two separate recovery sessions where they were assessed during a hypoxic exposure and at regular intervals for up to four hours post-exposure. Results demonstrated that RT, as measured by the PVT, significantly slowed during hypoxia compared to baseline and continued to be impaired until 60 min post-exposure. We assessed the mismatch negativity (MMN) and P3a ERP components in response to an auditory oddball paradigm and found a significant reduction in the amplitude of the MMN during hypoxia compared to baseline and that attenuation in amplitude persisted for up to 120 min post-exposure. Together, these results indicate that both RT and auditory processing showed a delayed recovery following hypoxia. We found no strong evidence for differential recovery speed based on recovery gas administered (21% versus 100% oxygen). These results have implications for guidance regarding return-to-duty status for military aviators following a hypoxic exposure.
Collapse
Affiliation(s)
- Kara J Blacker
- Naval Medical Research Unit-Dayton, Wright-Patterson AFB, OH, USA.
| | - Daniel G McHail
- Naval Medical Research Unit-Dayton, Wright-Patterson AFB, OH, USA.
| |
Collapse
|
9
|
Desai A, Benner L, Wu R, Gertsik L, Maruff P, Light GA, Uz T, Marek GJ, Zhu T. Phase 1 randomized study on the safety, tolerability, and pharmacodynamic cognitive and electrophysiological effects of a dopamine D 1 receptor positive allosteric modulator in patients with schizophrenia. Neuropsychopharmacology 2021; 46:1145-1151. [PMID: 33203954 PMCID: PMC8182805 DOI: 10.1038/s41386-020-00908-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 01/29/2023]
Abstract
ASP4345, a novel dopamine D1 receptor positive allosteric modulator, is being evaluated for the treatment of cognitive impairment associated with schizophrenia (CIAS). This phase 1 multiple ascending-dose study (NCT02720263) assessed the safety, tolerability, and pharmacodynamics of ASP4345 in patients with schizophrenia/schizoaffective disorder. Pharmacodynamic assessments were Cogstate cognitive tests and electrophysiological biomarkers, including gamma-band power and phase synchronization in response to 40-Hz auditory steady-state stimulation, as well as mismatch negativity (MMN) and P3a event-related potentials. The sample size determination was based on standard practice in assessing safety and tolerability of a new chemical entity. Data were summarized by conversion of this data into effect sizes using descriptive and inferential statistics. A total of 36 randomized patients received ASP4345 (3, 15, 50, and 150 mg; n = 9 each dose) and 12 patients received placebo. Patients in the ASP4345 group experienced 73 treatment-emergent adverse events (TEAEs) and 34 TEAEs were reported for the placebo group. The most common TEAEs were headache and somnolence and nearly all TEAEs were mild in severity. No changes in mood or self-reports of suicidal ideation/behavior were observed. Improvements in performance on cognitive tests were noted, which suggests a potential improvement in psychomotor function and visual attention. Furthermore, positive changes in neurophysiological biomarkers (auditory steady-state response [ASSR] and MMN) suggest improvement in information processing. The findings need to be confirmed in studies with a larger patient population. Nonetheless, the trends in safety and pharmacodynamic data support further clinical development of ASP4345 for the treatment of CIAS.
Collapse
Affiliation(s)
- Amit Desai
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA.
| | - Lauren Benner
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Ruishan Wu
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Lev Gertsik
- grid.490279.1California Clinical Trials Medical Group, Inc., Glendale, CA USA
| | | | - Gregory A. Light
- grid.266100.30000 0001 2107 4242University of California, San Diego, San Diego, CA USA
| | - Tolga Uz
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Gerard J. Marek
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Tong Zhu
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| |
Collapse
|
10
|
Blacker KJ, Seech TR, Funke ME, Kinney MJ. Deficits in Visual Processing During Hypoxia as Evidenced by Visual Mismatch Negativity. Aerosp Med Hum Perform 2021; 92:326-332. [PMID: 33875065 DOI: 10.3357/amhp.5735.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: Hypoxia is an ever-present threat in tactical aviation and gained recent attention due to its putative role in physiological episodes. Previous work has demonstrated that hypoxia negatively impacts a variety of sensory, cognitive, and motor systems. In particular, the visual system is one of the earliest systems affected by hypoxia. While the majority of previous studies have relied on self-report and behavioral testing, the use of event-related potentials as a novel tool to monitor responses to low oxygen in humans has recently been investigated. Specifically, ERP components that are evoked passively in response to unattended changes in background sensory stimulation have been explored.METHOD: Subjects (N 28) completed a continuous visuomotor tracking task while EEG was recorded. During the tracking task, a series of standard color checkerboard patterns were presented in the periphery while occasionally a deviant color checkerboard was presented. The visual mismatch negativity (MMN) component was assessed in response to the deviant compared to the standard stimuli. Subjects completed two sessions in counterbalanced order that only differed by the oxygen concentration breathed (10.6% vs. 20.4%).RESULTS: Results demonstrated a significant reduction in the amplitude of the visual MMN under hypoxic compared to normoxic conditions, showing a 50% reduction in amplitude during hypoxia. Our results suggest that during low-oxygen exposure the ability to detect environmental changes and process sensory information is impaired.DISCUSSION: The visual MMN may represent an early and reliable predictor of sensory and cognitive deficits during hypoxia exposure, which may be of great use to the aviation community.Blacker KJ, Seech TR, Funke ME, Kinney MJ. Deficits in visual processing during hypoxia as evidenced by visual mismatch negativity. Aerosp Med Hum Perform. 2021; 92(5):326332.
Collapse
|