Structural Brain Changes Related to Disease Duration in Patients with Asthma

Dyspnea is the impairing, cardinal symptom patients with asthma repeatedly experience over the course of the disease. However, its accurate perception is also crucial for timely initiation of treatment. Reduced perception of dyspnea is associated with negative treatment outcome, but the underlying brain mechanisms of perceived dyspnea in patients with asthma remain poorly understood. We examined whether increasing disease duration in fourteen patients with mild-to-moderate asthma is related to structural brain changes in the insular cortex and brainstem periaqueductal grey (PAG). In addition, the association between structural brain changes and perceived dyspnea were studied. By using magnetic resonance imaging in combination with voxel-based morphometry, gray matter volumes of the insular cortex and the PAG were analysed and correlated with asthma duration and perceived affective unpleasantness of resistive load induced dyspnea. Whereas no associations were observed for the insular cortex, longer duration of asthma was associated with increased gray matter volume in the PAG. Moreover, increased PAG gray matter volume was related to reduced ratings of dyspnea unpleasantness. Our results demonstrate that increasing disease duration is associated with increased gray matter volume in the brainstem PAG in patients with mild-to-moderate asthma. This structural brain change might contribute to the reduced perception of dyspnea in some patients with asthma and negatively impact the treatment outcome

The perception of dyspnea after bronchoconstriction and bronchodilation in patients with asthma

AbstractBackground: It is well documented that the perception of dyspnea (POD), subjectively reported by patients, is an important index used to guide treatment. The severity of dyspnea following methacholine-induced bronchoconstriction and added mechanical loads is increasing in popular. No formal attention has been addressed to the reduction in dyspnea following bronchodilators. Study objective: To investigate if the magnitude of dyspnea perceived by a subject is independent on the direction (e.g., bronchoconstriction or bronchodilation) of the change in airway resistance. Methods: The POD was measured in 26 mild–moderate asthmatic patients following bronchodilation, using β2-agonists, and following bronchoconstriction, induced by methacholine challenge, to almost the same magnitude. Results: The increase in forced expiratory volume in 1s (FEV1), 30min after the inhalation of β2-agonist (mean±SEM 22.3±0.8%), was associated with a statistically significant decrease (P<0.005) in the POD. The mean decrease in FEV1 following methacoline challenge, was 23±0.7% and was followed by a statistically significant increase (P<0.005) in the POD. The magnitude of the decrease in the POD following albuterol was almost identical to the magnitude of the increase in the POD following methacholine. Conclusions: In stable mild–moderate asthmatic patients, the changes in the magnitude of dyspnea, perceived by a subject, is independent on the direction of the change in the FEV1

The Relationship among the Inspiratory Muscle Strength, the Perception of Dyspnea and Inhaled Beta2-Agonists in Patients with Asthma

BACKGROUND: It is well documented that the perception of dyspnea (POD), subjectively reported by patients, is related to the activity and strength of the inspiratory muscles, and influences the use of 'as needed' beta2-agonists

Inspiratory muscle training in pulmonary rehabilitation program in COPD patients

SummaryMost pulmonary rehabilitation (PR) programs do not currently incorporate IMT in their PR programs for COPD patients.The aim of the present study was to assess the influence of adding IMT to the patients already involved in a rehabilitation program.Thirty-four patients with significant COPD were recruited for the study. All patients participated in a general exercise reconditioning (GER) program for 12 weeks. The patients were then randomized to receive IMT or sham IMT, in addition to GER for the next 6 months.Following three months of GER training there was a significant increase in the 6-min walk test (6MWT) (from mean±SEM 254±38 to 322±42m, p<0.01), and small but non-significant decreases in the perception of dyspnea (POD), and in the St. George Respiratory Questionnaire score (SGRQ). Following the addition of IMT to the GER program there was a significant increase in the PImax in the GER+IMT group (from 66±4.7 to 78±4.5cm H2O, p<0.01). This was accompanied by a significant improvement in the POD and a further significant improvement in the SGRQ score.IMT provides additional benefits to patients undergoing PR program and is worthwhile even in patients who have already undergone a GER program