Respiratory-related evoked potentials in chronic obstructive pulmonary disease and healthy aging

Influence of Sensory Monitoring on Speech Breathing Planning Processes: An Exploratory Study in Aging Speakers Reporting Dyspnea

PURPOSE

Previous studies have suggested that inspirations during speech pauses are influenced by the length of adjacent utterances, owing to respiratory motor planning and physiological recovery processes. The goal of this study was to examine how attention to respiratory sensations may influence these processes in aging speakers with dyspnea, by measuring the effect of sensory monitoring on the relationship between utterance length and the occurrence of inspirations, as well as on functional voice and respiratory measures.

METHOD

Seventeen adults aged 50 years and older with complaints of voicing-related dyspnea completed a repeated-measures protocol consisting of a 2-week baseline phase and a 4-week sensory monitoring phase. Audiovisual recordings of semistructured speech and self-report questionnaires were collected at study onset, after the baseline phase, and after the sensory monitoring phase. Repeated-measures logistic regressions were conducted to examine changes in the relationship between utterance length and the occurrence of inspirations in adjacent pauses, and repeated-measures analyses of variance were used to investigate any changes in functional voice and respiratory measures.

RESULTS

Planning and recovery processes appeared to remain constant across the baseline phase. From postbaseline to postsensory monitoring timepoints, a strengthening of the relationship between the presence of an inspiration during a speech pause and the length of the subsequent-but not preceding-utterance was noted. Significant improvements were noted in voice-related handicap from study onset to postsensory monitoring, but no changes were reported in respiratory comfort during speech.

CONCLUSIONS

Results suggest that respiratory planning processes, that is, the ability to plan breath intakes based on the length of upcoming utterances, may be modifiable behaviorally through targeted sensory monitoring. Further studies are warranted to validate the proposed role of respiratory sensation awareness in achieving skilled temporal coordination between voicing and breathing.

Neural oscillations underlying the neural gating of respiratory sensations in generalized anxiety disorder

Individuals with generalized anxiety disorder (GAD) have been shown to have altered neural gating of respiratory sensations (NGRS) using respiratory-related evoked potentials (RREP); however, corresponding neural oscillatory activities remain unexplored. The present study aimed to investigate altered NGRS in individuals with GAD using both time and time-frequency analysis. Nineteen individuals with GAD and 28 healthy controls were recruited. Paired inspiratory occlusions were delivered to elicit cortical neural activations measured from electroencephalography. The GAD group showed smaller N1 amplitudes to the first stimulus (S1), lower evoked gamma and larger evoked beta oscillations compared to controls. Both groups showed larger N1, P3, beta power and theta power in response to S1 compared to S2, suggesting a neural gating phenomenon. These findings suggest that N1, gamma and beta frequency oscillations may be indicators for altered respiratory sensation in GAD populations and that the N1, P3, beta and theta oscillations can reflect the neural gating of respiratory sensations.

Age-related changes in the neural gating of respiratory sensations in humans

Background

Neural gating of respiratory sensations (NGRS) characterises the brain's ability to filter out repetitive respiratory sensory stimuli. This mechanism plays a crucial role in the neural processing of respiratory stimuli. However, whether ageing affects NGRS in healthy adults is still unclear. Therefore, we aimed to measure the effect of age on NGRS as well as the corresponding S1 and S2 components of the respiratory-related evoked potentials (RREPs).

Methods

Three age groups of healthy adults participated in this study: a young group (YG; age 20-39 years), a middle-aged group (MG; age 40-59 years) and an old group (OG; age ≥60 years). NGRS was measured by the RREPs in the electroencephalogram in response to short-paired respiratory occlusion stimuli (S1 and S2). The S2/S1 ratio of the RREP N1 amplitude (the negative deflection of the RREP at ∼85-135 ms) was used to characterise NGRS.

Results

The results showed a significantly smaller N1 S2/S1 ratio in the YG than in the MG (p=0.01) and OG (p=0.03). Further analysis showed that the S1 N1 amplitude was larger for the YG compared with the MG (p=0.03) and OG (p=0.007). Moreover, age was significantly correlated with the N1 S2/S1 ratio (r=0.43), with higher age relating to higher N1 S2/S1 ratios.

Conclusions

The greater N1 S2/S1 ratios observed in older adults suggest that ageing has a negative impact on the NGRS. This might contribute to increased experiences of respiratory sensations such as dyspnoea in ageing adults.

Breathlessness in older adults: What we know and what we still need to know

Breathlessness is common among older adults, but it is often hidden as "normal aging "or considered narrowly as a symptom of cardio-respiratory diseases. Studies on breathlessness in older adults are mostly focused on specific diseases, whereas older adults are characterized by multimorbidity and multi-system age-related impairments. This article aims to provide an overview of what is known so far on breathlessness in the general population of older adults and identify areas for further research. Research shows that breathlessness in older adults is a multifactorial geriatric condition, crossing the borders of system-based impairments and diseases, and a valuable independent prognostic indicator for adverse outcomes. Further research needs to investigate (1) the multi-factorial mechanisms of breathlessness in community-dwelling older adults including the role of respiratory sarcopenia; (2) the influence of affective and cognitive changes of older age on the perception and report of breathlessness; (3) the best way to assess and use breathlessness for risk prediction of adverse outcomes in general geriatric assessments; and (4) the most appropriate multi-modal rehabilitation interventions and their outcomes. Clinicians need to shift their approach to dyspnea from a disease symptom to a multifactorial geriatric condition that should be proactively searched for, as it identifies higher risk for adverse outcomes, and can be addressed with evidence-based interventions that can improve the quality of life and may reduce the risk of adverse outcomes in older adults.