A wider pathological network underlying breathlessness and respiratory failure in amyotrophic lateral sclerosis

Fatigue and anxiety mediate the effect of dyspnea on quality of life in amyotrophic lateral sclerosis

Introduction: Dyspnea (or breathlessness) due to progressive neuromuscular respiratory failure is common in amyotrophic lateral sclerosis (ALS). It is associated with anxiety, depression and reduced quality of life (QoL). For effective treatment, it is essential to understand the relationships between dyspnea, anxiety, depression and QoL.Methods: The UK Trajectories of Outcomes in Neurological Conditions-ALS study (TONiC-ALS) collected self-report measures from patients with ALS. Ordinal scales were transformed to interval-scaled estimates by the Rasch Measurement model. They were subsequently included in a series of path models where the focal relationships were dyspnea to QoL and dyspnea to depression.Results: Path analyses using 1022 participants showed that 60.5% of the variance of QoL was explained by fatigue, anxiety, dyspnea and disability. For depression, 54.1% of the variance was explained by a model of these factors. Dyspnea played an important but mostly indirect role in influencing QoL and depressive symptoms. Disability was dominated by all other factors in the model.Discussion: Dyspnea in ALS influences quality of life and depression largely through indirect effects, principally acting via anxiety and fatigue. Recognition of this is essential for clinicians to understand where to intervene for greatest benefit. Researchers must be aware that studies of the effect of dyspnea on QoL and depression require path models, measuring both direct and indirect effects, as the impact of dyspnea is likely to be significantly miscalculated if only direct effects are assessed.

Delayed Clinical Manifestation of Parkinson's Disease Among Physically Active: Do Participants in a Long-Distance Ski Race Have a Motor Reserve?

Background:

Physical activity is associated with reduced risk of Parkinson’s disease (PD). The explanations for this association are not completely elucidated. We use long-term PD-incidence data from long-distance skiers to study the relationship between exercise and PD.

Objective:

We aimed to investigate if physical activity is associated with long-term lower risk of PD and if this association could be explained by physically active people being able to sustain more PD neuropathology before clinical symptoms, a motor reserve.

Methods:

Using a prospective observational design, we studied whether long-distance skiers of the Swedish Vasaloppet (n = 197,685), exhibited reduced incidence of PD compared to matched individuals from the general population (n = 197,684) during 21 years of follow-up (median 10, interquartile range (IQR) 5–15 years).

Results:

Vasaloppet skiers (median age 36.0 years [IQR 29.0–46.0], 38% women) had lower incidence of PD (HR: 0.71; 95 % CI 0.56–0.90) compared to non-skiers. When reducing risk for reverse causation by excluding PD cases within the first five years from race participation, there was still a trend for lower risk of PD (HR: 0.80; 95 % CI 0.62–1.03). Further, the PD prevalence converged between skiers and non-skiers after 15 years of follow-up, which is more consistent with a motor reserve in the physically active rather than neuroprotection.

Conclusions:

A physical active lifestyle is associated with reduced risk for PD. This association weakens with time and might be explained by a motor reserve among the physically active.

Tracheostomy in motor neurone disease

Tracheostomy-associated ventilation for the respiratory insufficiency caused by amyotrophic lateral sclerosis (motor neurone disease (MND)) is a complex issue with practical, ethical and economic dimensions. This article considers the current prevalence of tracheostomy in MND, the evidence for its benefit both for survival and quality of life, and the practicalities of its implementation. The decision to request invasive ventilatory support is among the most challenging for those living with MND. Neurologists should be prepared to discuss this option openly and objectively: we suggest a framework for discussion, including withdrawal of therapy.

Psychophysical Differences in Ventilatory Awareness and Breathlessness between Athletes and Sedentary Individuals

Purpose: Breathlessness is a complex set of symptoms that are comprised of both sensory and affective (emotional) dimensions. While ventilation is now understood to be a potential limiter to performance in highly-trained individuals, the contribution of breathlessness-anxiety in those nearing maximal ventilation during intense exercise has not yet been considered as a limiter to performance.

Methods: In this study, we compared the physiology and psychology of breathlessness in 20 endurance athletes with 20 untrained age- and sex-matched sedentary controls. Subjects completed baseline spirometry and anxiety questionnaires, an incremental exercise test to exhaustion and a steady-state hypercapnic ventilatory response test, with concurrent measures of breathlessness intensity and breathlessness-anxiety.

Results: Compared with sedentary subjects, athletes reported equivalent breathlessness intensity but greater breathlessness-anxiety at maximal exercise (athletes vs. sedentary (mean ± SD): breathlessness intensity (0–100%) 80.7 (22.7) vs. 72.5 (17.2), p = 0.21; breathlessness-anxiety (0–100%), 45.3 (36.3) vs. 22.3 (20.0), p = 0.02). Athletes operated at higher proportions of their maximal ventilatory capacity (MVV) (athletes vs. sedentary (mean ventilation ± SD; % MVV): 101.6 (27.2) vs. 73.7 (30.1), p = 0.003). In the athletes there was a positive linear correlation between ventilation and breathlessness score during the hypercapnic challenge that was not observed in the sedentary controls.

Conclusion: The results of this study indicate that whilst operating at high proportions of maximal ventilation, breathlessness-anxiety becomes increasingly prominent in athletes. Our results suggest that ventilatory perception pathways may be a target for improved athletic performance in some individuals.