Preservation of Neurovascular Coupling to Cognitive Activity in Anterior Cerebrovasculature During Incremental Ascent to High Altitude

Lefferts, Wesley K.; DeBlois, Jacob P.; Soriano, Jan Elaine; Mann, Leah M.; Rampuri, Zahrah H.; Herrington, Brittney; Thrall, Scott; Bird, Jordan; Harman, Taylor; Day, Trevor A.; Heffernan, Kevin S.; Brutsaert, Tom D.

doi:10.1089/ham.2019.0050

Cited by 7 publications

(7 citation statements)

References 35 publications

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“…Although this study took place as a part of a large expedition to HA in May 2018, the experimental question and design were planned a priori in advance. Some overlap in the participant pool and ancillary cardiorespiratory measures exists with Childebayeva et al (2019), Leacy et al (2021) and Lefferts et al (2019a;2019b).…”

Section: New Findingsmentioning

confidence: 99%

The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnoea

Holmström

Bird

Thrall

et al. 2020

Experimental Physiology

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Voluntary apnoea causes splenic contraction and reductions in heart rate (HR; bradycardia), and subsequent transient increases in haemoglobin concentration ([Hb]). Ascent to high altitude (HA) induces systemic hypoxia and reductions in oxygen saturation (S pO 2), which may cause tonic splenic contraction, which may contribute to haematological acclimatization associated with HA ascent. We measured resting cardiorespiratory variables (HR, S pO 2 , [Hb]) and resting splenic volume (via ultrasound) during incremental ascent from 1400 m (day 0) to 3440 m (day 3), 4240 m (day 7) and 5160 m (day 10) in non-acclimatized native lowlanders during assent to HA in the Nepal Himalaya. In addition, apnoea-induced responses in HR, S pO 2 and splenic volume were measured before and after two separate voluntary maximal apnoeas (A1

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Section: New Findingsmentioning

confidence: 99%

The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnoea

Holmström

Bird

Thrall

et al. 2020

Experimental Physiology

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“…For the N-Back Number Task , impaired performance was found at the highest altitude tested, 5160 m (16,929 ft) [ 51 ], and in the only laboratory test at 4500 m (14,764 ft), by Williams et al (2019) [ 75 ]. The Stroop Test was used ten times [ 23 , 27 , 46 , 50 , 52 , 59 , 62 , 64 , 66 , 74 ]. In the field examinations, the results were very heterogeneous; twice there was no disturbance [ 23 , 46 ], twice there was a worsening [ 50 , 59 ], but on the follow-up examination there was no further deviation, and once there was an improvement [ 52 ].…”

Section: Resultsmentioning

confidence: 99%

“…The Stroop Test was used ten times [ 23 , 27 , 46 , 50 , 52 , 59 , 62 , 64 , 66 , 74 ]. In the field examinations, the results were very heterogeneous; twice there was no disturbance [ 23 , 46 ], twice there was a worsening [ 50 , 59 ], but on the follow-up examination there was no further deviation, and once there was an improvement [ 52 ]. In the laboratory studies, four out of five tests showed impaired functions in the subjects [ 27 , 62 , 66 , 74 ]; the altitudes investigated ranged from 3500 m (11,483 ft) [ 62 ] to 7620 m (25,000 ft) [ 27 ].…”

Section: Resultsmentioning

confidence: 99%

Cognition and Neuropsychological Changes at Altitude—A Systematic Review of Literature

Bliemsrieder

Weiss²,

Fischer³

et al. 2022

Brain Sciences

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High-altitude (HA) exposure affects cognitive functions, but studies have found inconsistent results. The aim of this systematic review was to evaluate the effects of HA exposure on cognitive functions in healthy subjects. A structural overview of the applied neuropsychological tests was provided with a classification of superordinate cognitive domains. A literature search was performed using PubMed up to October 2021 according to PRISMA guidelines. Eligibility criteria included a healthy human cohort exposed to altitude in the field (at minimum 2440 m [8000 ft]) or in a hypoxic environment in a laboratory, and an assessment of cognitive domains. The literature search identified 52 studies (29 of these were field studies; altitude range: 2440 m–8848 m [8000–29,029 ft]). Researchers applied 112 different neuropsychological tests. Attentional capacity, concentration, and executive functions were the most frequently studied. In the laboratory, the ratio of altitude-induced impairments (64.7%) was twice as high compared to results showing no change or improved results (35.3%), but altitudes studied were similar in the chamber compared to field studies. In the field, the opposite results were found (66.4 % no change or improvements, 33.6% impairments). Since better acclimatization can be assumed in the field studies, the findings support the hypothesis that sufficient acclimatization has beneficial effects on cognitive functions at HA. However, it also becomes apparent that research in this area would benefit most if a consensus could be reached on a standardized framework of freely available neurocognitive tests.

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“… 11 The plateau has thin air (approximately 60–70% of the air density at sea level), low-oxygen levels (35–40% lower than the oxygen content at sea level) and low-pressure levels (only half of the pressure at sea level). 12 13 Due to the differences in regional climates and local traditional lifestyles, the prevalence of stroke and stroke risk factors varies. 14 15 At least 5.7% of the population worldwide lives at altitudes above 1500 m. Some studies have found 16 17 that the morbidity and mortality of stroke among residents in plateau areas are lower than those among residents in plain areas.…”

Section: Introductionmentioning

confidence: 99%

“…Some environmental factors, such as high-altitude residence, are also associated with stroke 11. The plateau has thin air (approximately 60–70% of the air density at sea level), low-oxygen levels (35–40% lower than the oxygen content at sea level) and low-pressure levels (only half of the pressure at sea level) 12 13. Due to the differences in regional climates and local traditional lifestyles, the prevalence of stroke and stroke risk factors varies 14 15.…”

Section: Introductionmentioning

confidence: 99%

Prevalence of stroke and associated risk factors: a population-based cross-sectional study from the Qinghai-Tibet Plateau of China

et al. 2022

BMJ Open

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Background and objectivesThe epidemiology of stroke at high altitudes has not been extensively studied, especially at heights of 4000 m and above. Thus, stroke prevention and treatment at high altitudes are challenging. We conducted a cross-sectional study to estimate the prevalence of stroke, the detection rate of individuals at high risk of stroke and the risk factors for stroke in the Qinghai-Tibet Plateau in China, a high altitude plateau that inhabits approximately 15 million people.DesignA population-based cross-sectional study in the Qinghai-Tibet Plateau.SettingData were collected from participants through face-to-face screening using a primary screening table. The table relied on the China National Stroke Screening and Prevention Project.ParticipantsA total of 10 700 residents aged ≥40 years and living on the Qinghai-Tibet Plateau for more than 6 months participated from January 2019 to December 2021.Main outcome measuresThe primary screening table included basic demographic information, medical history information, personal lifestyle habits and physical examination information.ResultsA total of 10 056 people were included in the analysis. The prevalence of stroke was 2.3% (95% CI 2.0% to 2.6%), and the detection rate of individuals at high risk of stroke was 26.2% (95% CI 25.3% to 27.0%). The prevalence of stroke and the detection rate of individuals at high risk of stroke increased with altitude (p<0.01), and the prevalence of stroke at high altitudes was almost 2.2 times that at mid-altitudes (p<0.01). After full adjustments, age, residence, hypertension, family history of stroke and smoking were significantly associated with stroke (p<0.05).ConclusionsThe prevalence of stroke, the related risk factors and the detection rate of high-risk individuals were clarified. The prevalence rates of hypertension, overweight or obesity and diabetes in the Qinghai-Tibet Plateau were all higher than the Chinese average. Higher-altitude exposure may be an independent risk factor for stroke.

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Preservation of Neurovascular Coupling to Cognitive Activity in Anterior Cerebrovasculature During Incremental Ascent to High Altitude

Cited by 7 publications

References 35 publications

The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnoea

The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnoea

Cognition and Neuropsychological Changes at Altitude—A Systematic Review of Literature

Prevalence of stroke and associated risk factors: a population-based cross-sectional study from the Qinghai-Tibet Plateau of China

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