Psycho-demographic profile in severe asthma and effect of emotional mood disorders and hyperventilation syndrome on quality of life.

BACKGROUND: Severe asthma affects a small population but carries a high psychopathological risk. Therefore, the psychodemographic profile of these patients is of interest. A substantial prevalence of anxiety, depression, alexithymia and hyperventilation syndrome in severe asthma is known, but contradictory results have been observed. These factors can also affect patients' quality of life. For this reasons, our purpose is to evaluate the psychodemographic profile of patients with severe asthma and assess the prevalence of anxiety, depression, alexithymia and hyperventilation syndrome and their impact on the quality of life of patients with severe asthma. METHODS: A cross-sectional study of 63 patients with severe asthma. Their psychodemographic profile was evaluated using the Hospital Anxiety and Depression Scale (HADS), Toronto Alexithymia Scale (TAS-20), Nijmegen questionnaire and Asthma Control Test (ACT) to determine the state of anxiety and depression, alexithymia, hyperventilation syndrome and control of asthma, respectively. Quality of life was assessed with the Mini Asthma Quality of Life Questionnaire (Mini-AQLQ). RESULTS: The mean age was 60 ± 13.6 years. Personal psychopathological histories were found in 65.1% of participants, and 8% reported previous suicidal attempts. The rate of anxiety and/or depression (HADS ≥ 11) was 68.3%. These patients present higher scores on the TAS-20 (p < 0.001) for the level of dyspnea (p = 0.021), and for emotional function (p = 0.017) on the Mini-AQLQ, compared with patients without anxiety or depression. Alexithymia (TAS-20 ≥ 61) was observed in 42.9% of patients; these patients were older (p = 0.037) and had a higher HADS score (p = 0.019) than patients with asthma without alexithymia. On the other hand, patients with hyperventilation syndrome (Nijmegen ≥ 23) scored higher on the HADS (p < 0.05), on the Mini-AQLQ (p = 0.002) and on the TAS-20 (p = 0.044) than the group without hyperventilation syndrome. Quality of life was related to anxiety-depression symptomatology (r = - 0.302; p = 0.016) and alexithymia (r = - 0.264; p = 0.036). Finally, the Mini-AQLQ total score was associated with the Nijmegen questionnaire total score (r = - 0.317; p = 0.011), and the activity limitation domain of the Mini-AQLQ correlated with the ACT total score (r = 0.288; p = 0.022). CONCLUSIONS: The rate of anxiety, depression, alexithymia and hyperventilation syndrome is high in patients with severe asthma. Each of these factors is associated with a poor quality of life.

Panic disorder respiratory subtype: psychopathology and challenge tests - an update

Panic disorder (PD) pathophysiology is very heterogeneous, and the discrimination of distinct subtypes could be very useful. A subtype based on respiratory symptoms is known to constitute a specific subgroup. However, evidence to support the respiratory subtype (RS) as a distinct subgroup of PD with a well-defined phenotype remains controversial. Studies have focused on characterization of the RS based on symptoms and response to CO2. In this line, we described clinical and biological aspects focused on symptomatology and CO2 challenge tests in PD RS. The main symptoms that characterize RS are dyspnea (shortness of breath) and a choking sensation. Moreover, patients with the RS tended to be more responsive to CO2 challenge tests, which triggered more panic attacks in this subgroup. Future studies should focus on discriminating respiratory-related clusters and exploring psychophysiological and neuroimaging outcomes in order to provide robust evidence to confirm RS as a distinct subtype of PD.

Panic disorder respiratory subtype: psychopathology and challenge tests - an update.

Panic disorder (PD) pathophysiology is very heterogeneous, and the discrimination of distinct subtypes could be very useful. A subtype based on respiratory symptoms is known to constitute a specific subgroup. However, evidence to support the respiratory subtype (RS) as a distinct subgroup of PD with a well-defined phenotype remains controversial. Studies have focused on characterization of the RS based on symptoms and response to CO2. In this line, we described clinical and biological aspects focused on symptomatology and CO2 challenge tests in PD RS. The main symptoms that characterize RS are dyspnea (shortness of breath) and a choking sensation. Moreover, patients with the RS tended to be more responsive to CO2 challenge tests, which triggered more panic attacks in this subgroup. Future studies should focus on discriminating respiratory-related clusters and exploring psychophysiological and neuroimaging outcomes in order to provide robust evidence to confirm RS as a distinct subtype of PD.

Behavioural and psychological characteristics in Pitt-Hopkins syndrome: a comparison with Angelman and Cornelia de Lange syndromes.

BACKGROUND: Pitt-Hopkins syndrome (PTHS) is a genetic neurodevelopmental disorder associated with intellectual disability. Although the genetic mechanisms underlying the disorder have been identified, description of its behavioural phenotype is in its infancy. In this study, reported behavioural and psychological characteristics of individuals with PTHS were investigated in comparison with the reported behaviour of age-matched individuals with Angelman syndrome (AS) and Cornelia de Lange syndrome (CdLS). METHODS: Questionnaire data were collected from parents/caregivers of individuals with PTHS (n = 24), assessing behaviours associated with autism spectrum disorder (ASD), sociability, mood, repetitive behaviour, sensory processing, challenging behaviours and overactivity and impulsivity. For most measures, data were compared to data for people with AS (n = 24) and CdLS (n = 24) individually matched by adaptive ability, age and sex. RESULTS: Individuals with PTHS evidenced significantly higher levels of difficulties with social communication and reciprocal social interaction than individuals with AS, with 21 of 22 participants with PTHS meeting criteria indicative of ASD on a screening instrument. Individuals with PTHS were reported to be less sociable with familiar and unfamiliar people than individuals with AS, but more sociable with unfamiliar people than individuals with CdLS. Data also suggested areas of atypicality in sensory experiences. Challenging behaviours were reported frequently in PTHS, with self-injury (70.8%) occurring at significantly higher rates than in AS (41.7%) and aggression (54.2%) occurring at significantly higher rates than in CdLS (25%). Individuals with PTHS also evidenced lower reported mood than individuals with AS. CONCLUSIONS: Behaviours which may be characteristic of PTHS include those associated with ASD, including deficits in social communication and reciprocal social interaction. High rates of aggression and self-injurious behaviour compared to other genetic syndrome groups are of potential clinical significance and warrant further investigation. An atypical sensory profile may also be evident in PTHS. The specific aetiology of and relationships between different behavioural and psychological atypicalities in PTHS, and effective clinical management of these, present potential topics for future research.

Going to Altitude with a Preexisting Psychiatric Condition.

Psychiatric disorders have a high lifetime prevalence affecting about 30% of the global population. Not much is known about high altitude (HA) sojourns in individuals living with a psychiatric condition. This lack of scientific evidence contrasts with the anticipated increase in numbers of individuals with preexisting psychiatric conditions seeking medical advice on HA exposure. Not only are there risks associated with a HA climb, but physical activity in general is known to improve symptoms of many psychiatric disorder and enhance measures of mental well-being like quality of life and resilience. There are additional positive effects of alpine environments on mental health beyond those of physical activity. All individuals going to HA with a preexisting psychiatric condition should be in a state of stable disease with no recent change in medication. Specific considerations and recommendations apply to individual psychiatric disorders. During the HA sojourn the challenge is to separate altitude-related symptoms such as insomnia from prodromal symptoms of the underlying disorder (e.g., depressive episode) or altitude-related hyperventilation from panic attacks. In case an individual with preexisting anxiety disorder decides to go to HA there might be a predisposition toward acute mountain sickness (AMS), but it should always be considered that many symptoms of anxiety and AMS overlap. Any medication that is anticipated to be taken during ascent or at HA should be tested for compatibility with the psychiatric condition and medication before the trip.

Isolating the independent effects of hypoxia and hyperventilation-induced hypocapnia on cerebral haemodynamics and cognitive function.

NEW FINDINGS: What is the central question of this study? What are the independent effects of hypoxia and hypocapnia on cerebral haemodynamics and cognitive function? What is the main finding and its importance? Exposure to hyperventilation-induced hypocapnia causes cognitive impairment in both normoxia and hypoxia. In addition, supplementation of carbon dioxide during hypoxia alleviates the cognitive impairment and reverses hypocapnia-induced vasoconstriction of the cerebrovasculature. These data provide new evidence for the independent effect of hypocapnia on the cognitive impairment associated with hypoxia. ABSTRACT: Hypoxia, which is accompanied by hypocapnia at altitude, is associated with cognitive impairment. This study examined the independent effects of hypoxia and hypocapnia on cognitive function and assessed how changes in cerebral haemodynamics may underpin cognitive performance outcomes. Single reaction time (SRT), five-choice reaction time (CRT) and spatial working memory (SWM) tasks were completed in 20 participants at rest and after 1 h of isocapnic hypoxia (IH, end-tidal oxygen partial pressure ( PETO2 ) = 45 mmHg, end-tidal carbon dioxide partial pressure ( PETCO2 ) clamped at normal) and poikilocapnic hypoxia (PH, PETO2  = 45 mmHg, PETCO2 not clamped). A subgroup of 10 participants were also exposed to euoxic hypocapnia (EH, PETO2  = 100 mmHg, PETCO2 clamped 8 mmHg below normal). Middle cerebral artery velocity (MCAv) and prefrontal cerebral haemodynamics were measured with transcranial Doppler and near infrared spectroscopy, respectively. IH did not affect SRT and CRT performance from rest (566 ± 50 and 594 ± 70 ms), whereas PH (721 ± 51 and 765 ± 48 ms) and EH (718 ± 55 and 755 ± 34 ms) slowed response times (P < 0.001 vs. IH). Performance on the SWM task was not altered by condition. MCAv increased during IH compared to PH (P < 0.05), which was unchanged from rest. EH caused a significant fall in MCAv and prefrontal cerebral oxygenation (P < 0.05 vs. baseline). MCAv was moderately correlated to cognitive performance (R2  = 0.266-0.289), whereas prefrontal cerebral tissue perfusion and saturation were not (P > 0.05). These findings reveal a role of hyperventilation-induced hypocapnia per se on the development of cognitive impairment during normoxic and hypoxic exposures.

The Effect of a Brief Mindfulness Training on Distress Tolerance and Stress Reactivity.

Poor distress tolerance (DT) is considered an underlying facet of anxiety, depression, and a number of other psychological disorders. Mindfulness may help to increase DT by fostering an attitude of acceptance or nonjudgment toward distressing experiences. Accordingly, the present study examined the effects of a brief mindfulness training on tolerance of different types of distress, and tested whether trait mindfulness moderates the effect of such training. Undergraduates (n = 107) naïve to mindfulness completed a measure of trait mindfulness and underwent a series of stress tasks (cold pressor, hyperventilation challenge, neutralization task) before and after completing a 15-minute mindfulness training or a no-instruction control in which participants listened to relaxing music. Participants in the mindfulness condition demonstrated greater task persistence on the hyperventilation task compared to the control group, as well as a decreased urge to neutralize the effects of writing an upsetting sentence. No effect on distress ratings during the tasks were found. Overall trait mindfulness did not significantly moderate task persistence, but those with lower scores on the act with awareness facet of mindfulness demonstrated greater relative benefit of mindfulness training on the hyperventilation challenge. Mediation analyses revealed significant indirect effects of mindfulness training on cold pressor task persistence and urges to neutralize through the use of the nonjudge and nonreact facets of mindfulness. These results suggest that a brief mindfulness training can increase DT without affecting the subjective experience of distress.

Association of dysfunctional breathing with health-related quality of life: A cross-sectional study in a young population.

Symptomatic hyperventilation (SH) is a pathological condition that manifests with breathlessness, dyspnea, light-headedness, anxiety, and paresthesia. However, little is known about the prevalence of SH and its association with health-related quality of life (HRQoL) in a young population. The Nijmegen questionnaire (NQ), which measures severity of SH, had not previously been cross-culturally translated into Korean. In this study, the NQ was cross-culturally translated into Korean (KNQ), using translation and back-translation methods. To examine the reliability and validity levels of the KNQ, as well as its association with HRQoL, 237 college students (21.38 ± 2.45 years) were asked to complete the KNQ, the Korean version of the general health questionnaire (K-GHQ-30) and the short form-36 (K-SF-36). The KNQ showed satisfactory reliability (Cronbach's α = 0.878). In the construct validity test, four factors (neuropsychological, respiratory, neurogastrointestinal, and neuromuscular) were extracted (% of total variance = 59.8). Using a KNQ cut-off score of 23 points, the prevalence of SH was 22.8%. Physical and mental HRQoL levels estimated by the K-GHQ-30 score and the 8 subscale scores of the K-SF-36 were lower in the SH group than in those of the non-SH group. It is concluded that the cross-culturally translated KNQ is reliable and valid, and management of SH may prevent a reduction in physical and mental HRQoL in a young population.

Pitt-Hopkins Syndrome: A Unique Case Study.

OBJECTIVES: Pitt-Hopkins syndrome (PTHS) is a rare genetic disorder caused by insufficient expression of the TCF4 gene. Most cases are characterized by severe intellectual disability, absent speech, motor delays, and autism spectrum disorder. Many have abnormal brain imaging, dysmorphic facial features, and medical comorbidities: myopia, constipation, epilepsy, and apneic spells. The present case study expands existing understanding of this disorder by presenting a unique phenotype with higher cognitive abilities and fewer medical comorbidities. METHODS: The present case study reports on a 13-year-old, Caucasian male with a recent diagnosis of PTHS following genetic testing (i.e., whole exome sequencing). He was referred for a neuropsychological evaluation to document his neurocognitive functioning to assist with intervention planning. RESULTS: Evaluation of intellectual, attention/executive, memory, visual-motor/fine-motor, academic, adaptive, and emotional/behavioral functioning revealed global impairment across all areas of functioning. However, he demonstrated abilities beyond what has been detailed in the literature, including use of full sentences, capacity to learn and solve novel problems, basic academic functioning, and independent ambulation. CONCLUSIONS: Children with PTHS may demonstrate a spectrum of abilities beyond what has been documented in the literature thus far. Failure to recognize this spectrum can result in late identification of an accurate diagnosis. (JINS, 2018, 24, 995-1002).

Pitt-Hopkins Syndrome: A Review of Current Literature, Clinical Approach, and 23-Patient Case Series.

Pitt-Hopkins syndrome (PTHS) is a rare, genetic disorder caused by a molecular variant of TCF4 which is involved in embryologic neuronal differentiation. PTHS is characterized by syndromic facies, psychomotor delay, and intellectual disability. Other associated features include early-onset myopia, seizures, constipation, and hyperventilation-apneic spells. Many also meet criteria for autism spectrum disorder. Here the authors present a series of 23 PTHS patients with molecularly confirmed TCF4 variants and describe 3 unique individuals. The first carries a small deletion but does not exhibit the typical facial features nor the typical pattern of developmental delay. The second exhibits typical facial features, but has attained more advanced motor and verbal skills than other reported cases to date. The third displays typical features of PTHS, however inherited a large chromosomal duplication involving TCF4 from his unaffected father with somatic mosaicism. To the authors' knowledge, this is the first chromosomal duplication case reported to date.

Blood-Injection-Injury (B-I-I) Specific Phobia Affects the Outcome of Hypoxic Challenge Testing.

BACKGROUND: Blood-injection-injury (B-I-I) phobia is capable of producing inaccurate hypoxic challenge testing results due to anxiety-induced hyperventilation. CASE REPORT: A 69-yr-old woman with a history of hypersensitivity pneumonitis, restrictive spirometry, exercise desaturation requiring supplementary oxygen on mobilizing, reduced DLco, and B-I-I phobia was referred for hypoxic challenge testing (HCT) to assess in-flight oxygen requirements. HCT was performed by breathing a 15% FIo2 gas mixture, simulating the available oxygen in ambient air onboard aircraft pressurized to an equivalent altitude of 8000 ft. Spo2 fell to a nadir value of 81% during HCT, although it rapidly increased to 89% during the first of two attempts at blood gas sampling. A resultant blood gas sample showed an acceptable Po2 outside the criteria for recommending in-flight oxygen and a reduced Pco2. Entering the nadir Spo2 value into the Severinghaus equation gives an estimated arterial Po2 of 6 kPa (45 mmHg), which was felt to be more representative of resting values during HCT, and in-flight oxygen was recommended. DISCUSSION: While hyperventilation is an expected response to hypoxia, transient rises in Spo2 coinciding with threat of injury are likely to be attributable to emotional stress-induced hyperventilation, characteristic of B-I-I specific phobia and expected during the anticipation of exteroceptive threat, even in normal subjects. In summary, should excessive hyperventilation be detected during HCT and coincide with transient increases in Spo2, HCT should be repeated using Spo2 only as a guide to the level of hypoxemia, and Spo2 maintained using supplementary oxygen in accordance with alternative methods described in guidelines.Spurling KJ, McGoldrick VP. Blood-injection-injury (B-I-I) specific phobia affects the outcome of hypoxic challenge testing. Aerosp Med Hum Perform. 2017; 88(5):503-506.

Low pre-treatment end-tidal CO2 predicts dropout from cognitive-behavioral therapy for anxiety and related disorders.

Recent clinical trial research suggests that baseline low end-tidal CO2 (ETCO2, the biological marker of hyperventilation) may predict poorer response to cognitive-behavioral therapy (CBT) for anxiety-related disorders. The present study examined the predictive value of baseline ETCO2 among patients treated for such disorders in a naturalistic clinical setting. Sixty-nine adults with a primary diagnosis of a DSM-5 anxiety disorder, obsessive-compulsive disorder, or posttraumatic stress disorder completed a 4-min assessment of resting ETCO2, and respiration rate (the first minute was analyzed). Lower ETCO2 was not associated with a diagnosis of panic disorder, and was associated with lower subjective distress ratings on certain measures. Baseline ETCO2 significantly predicted treatment dropout: those meeting cutoff criteria for hypocapnia were more than twice as likely to drop out of treatment, and ETCO2 significantly predicted dropout beyond other pre-treatment variables. Weekly measurement suggested that the lower-ETCO2 patients who dropped out were not responding well to treatment prior to dropout. The present results, along with previous clinical trial data, suggest that lower pre-treatment ETCO2 is a negative prognostic indicator for CBT for anxiety-related disorders. It is suggested that patients with lower ETCO2 might benefit from additional intervention that targets respiratory abnormality.

A 56-Year-Old, Otherwise Healthy Woman Presenting With Light-headedness and Progressive Shortness of Breath.

A 56-year-old white woman was referred to the pulmonary clinic for evaluation of unexplained shortness of breath. She enjoyed good health until 3 months prior to this visit when she reported experiencing recurrent episodes of shortness of breath and oppressive retrosternal chest discomfort with radiation to the neck. Episodes lasting 5 to 10 min often occurred at rest and were inconsistently related to physical activity. These symptoms became progressively worse and were often associated with light-headedness and presyncope. Her past medical history was uneventful apart from a prior diagnosis of breast cysts and suspected prolactinoma. Her symptoms escalated to such a level that she was forced to seek urgent medical attention at our institutional ED on two separate occasions in the preceding weeks. These visits precipitated a number of investigations and, eventually, a referral to the pulmonary clinic.

Primary Hyperventilation in the Emergency Department: A First Overview.

BACKGROUND: Primary hyperventilation is defined as a state of alveolar ventilation in excess of metabolic requirements, leading to decreased arterial partial pressure of carbon dioxide. The primary aim of this study was to characterise patients diagnosed with primary hyperventilation in the ED. METHODS: Our retrospective cohort study comprised adult (≥16 years) patients admitted to our ED between 1 January 2006 and 31 December 2012 with the primary diagnosis of primary (=psychogenic) hyperventilation. RESULTS: A total of 616 patients were eligible for study. Participants were predominantely female (341 [55.4%] female versus 275 [44.6%] male respectively, p <0.01). The mean age was 36.5 years (SD 15.52, range 16-85). Patients in their twenties were the most common age group (181, 29.4%), followed by patients in their thirties (121, 19.6%). Most patients presented at out-of-office hours (331 [53.7%]. The most common symptom was fear (586, 95.1%), followed by paraesthesia (379, 61.5%) and dizziness (306, 49.7%). Almost a third (187, 30.4%) of our patients had previously experienced an episode of hyperventilation and half (311, 50.5%) of patients had a psychiatric co-morbidity. CONCLUSION: Hyperventilation is a diagnostic chimera with a wide spectrum of symptoms. Patients predominantly are of young age, female sex and often have psychiatric comorbidities. The severity of symptoms accompanied with primary hyperventilation most often needs further work-up to rule out other diagnosis in a mostly young population. In the future, further prospective multicentre studies are needed to evaluate and establish clear diagnostic criteria for primary hyperventilation and possible screening instruments.

Acid-base dysregulation and chemosensory mechanisms in panic disorder: a translational update.

Panic disorder (PD), a complex anxiety disorder characterized by recurrent panic attacks, represents a poorly understood psychiatric condition which is associated with significant morbidity and an increased risk of suicide attempts and completed suicide. Recently however, neuroimaging and panic provocation challenge studies have provided insights into the pathoetiology of panic phenomena and have begun to elucidate potential neural mechanisms that may underlie panic attacks. In this regard, accumulating evidence suggests that acidosis may be a contributing factor in induction of panic. Challenge studies in patients with PD reveal that panic attacks may be reliably provoked by agents that lead to acid-base dysbalance such as CO2 inhalation and sodium lactate infusion. Chemosensory mechanisms that translate pH into panic-relevant fear, autonomic, and respiratory responses are therefore of high relevance to the understanding of panic pathophysiology. Herein, we provide a current update on clinical and preclinical studies supporting how acid-base imbalance and diverse chemosensory mechanisms may be associated with PD and discuss future implications of these findings.

Fatal and nonfatal drowning outcomes related to dangerous underwater breath-holding behaviors - New York State, 1988-2011.

Drowning is an important cause of preventable injury and mortality, ranking fifth among leading causes of unintentional injury death in the United States. In 2011, two healthy young men died in a drowning incident at a New York City (NYC)-regulated swimming facility. The men became unconscious underwater after performing intentional hyperventilation before submersion. The phenomenon of healthy swimmers becoming unconscious underwater has been described elsewhere as hypoxic blackout. Prompted by this incident, the NYC Department of Health and Mental Hygiene (DOHMH) in collaboration with the New York State Department of Health (SDOH) conducted a case review of New York state fatal and nonfatal drownings reported during 1988-2011 to investigate similar behaviors in other incidents. DOHMH identified 16 cases, three in NYC, with a consistent set of voluntary behaviors associated with unintentional drowning and designated this class of behaviors as "dangerous underwater breath-holding behaviors" (DUBBs). For this small sample, the frequency of different DUBBs varied by age and swimming level, and practicing more than one DUBB increased the risk for fatality. This research contributes to the literature on drowning by focusing on contributing behaviors rather than drowning outcomes. NYC recently enacted public health education and regulations that discourage DUBBs; these interventions have the potential to effectively reduce unintentional drowning related to these behaviors and could be considered by other municipalities and jurisdictions.

Interoceptive exposure exercises for social anxiety.

Individuals with social anxiety disorder (SAD) commonly experience panic attacks and evidence increased anxiety sensitivity (AS) specific to noticeable anxiety sensations. Interoceptive exposure (IE) is an effective treatment for reducing AS, but few IE tasks target fears of blushing, sweating, or trembling, which are incorporated within AS social concerns and especially feared by individuals with SAD. The primary study aims were trifold: (1) identify novel IE tasks that produce blushing, sweating, and/or trembling; (2) assess the intensity of sensations and anxiety produced by a series of novel and validated IE tasks; and (3) evaluate the incremental validity of combining an IE task and a speech task. Individuals (N = 55) with heightened fear of noticeably blushing, sweating, and/or trembling completed a control task and 8 IE tasks (e.g., hot sauce, hyperventilation). All tasks produced greater intensity of anxiety and sensations compared to the control task (ps < .001; range of η(p)(2) = .20-.50). Responses to the combination of an IE task and social task compared to a social task alone did not differ significantly. Future directions for research and clinical implications of the findings are discussed.

Voluntary suppression of hyperthermia-induced hyperventilation mitigates the reduction in cerebral blood flow velocity during exercise in the heat.

Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (PaCO2 ) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on PaCO2 , CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (Tes) showed that minute ventilation increased linearly with rising Tes during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1°C Tes; P < 0.001). Normal breathing led to decreases in estimated PaCO2 and middle cerebral artery blood flow velocity (MCAV) with rising Tes, but controlled breathing attenuated those reductions (estimated PaCO2 -3.4 vs. -0.8 mmHg; MCAV -10.4 vs. -3.9 cm/s at +1.1°C Tes; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance (P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in PaCO2 and CBF.

Functional somatic syndromes: asking about exclusionary medical conditions results in decreased prevalence and overlap rates.

BACKGROUND: The diagnosis of functional somatic syndromes (FSS) requires 1) presence of somatic symptoms, and 2) absence of medical conditions potentially accounting for these symptoms. Due to the limited feasibility of medical examinations, epidemiological research on FSS has neglected to assess the second criterion. Our objective was therefore to evaluate the implications of considering information on exclusionary medical conditions in epidemiological research on FSS. METHODS: A survey among 3'054 students was conducted. We compared prevalence rates and overlap of 17 FSS obtained by: 1) a symptom-based strategy and 2) a symptom-and-exclusion-based strategy including information on exclusionary medical conditions. RESULTS: The symptom-and-exclusion-based strategy led to a marked decrease in prevalence rates compared to the symptom-based strategy. Furthermore, it resulted in fewer individuals who were affected by multiple FSS. CONCLUSIONS: Adding self-reported information on exclusionary medical conditions leads to a significant decrease in the prevalence and overlap of FSS. More rigorous approaches to studying FSS should be adopted.