The categories and items of the EK scale were relevant and valid as means of discriminating between levels of functional performance in the population studied which was evidence of content and construct validity.

No abstract

Bronchial pressure measured by means of a Pitot static probe, esophageal pressure, and airflow were monitored during forced lung deflations in six anesthetized dogs. Dynamic transmural pressure-cross-sectional area area curves (Ptm-A curves) were constructed for three intrathoracic tracheal positions and one right lower lobal bronchial position. From the Ptm-A curves the maximal possible flow (Vmax) through the airways at each of the four positions was calculated and compared with the overall maximal flow obtained during the same deflation. The peak of the maximal expiratory flow-volume curve (MEFV curve) equaled the calculated Vmax at more than one position in the trachea but did not reach the Vmax calculated for the more peripheral position. During the transition between the peak and the plateau of the MEFV curve, the Ptm-A curve often changed shape, indicating an abrupt change in the "tube law," probably due to changes in axial tension of the airway. During the flow-volume curve plateau, measured flow was near an estimated Vmax at a single point in the trachea. At lower lung volumes where the MEFV curve descends from the plateau, measured flow equaled Vmax calculated for the right lower lobe position. This indicates that after an initial period with no localized choking a "choke point" develops and eventually moves toward the periphery. We conclude that measurement of dynamic Ptm-A curves allows a precise prediction of maximal expiratory flows from the properties of the airways.

The purpose of this study was to describe functional ability, muscle strength, forced vital capacity, and clinical events in participants with Duchenne muscular dystrophy (DMD) or spinal muscular atrophy (SMA) in the non‐ambulatory stages of the diseases. Nineteen non‐ambulatory participants with DMD (all males; 13 to 24 years) and 13 with SMA (six males, seven females; 11 to 57 years) were assessed once a year over 5 years. The assessments comprised functional ability measured with the EK scale and upper extremity grade, muscle strength measured with the manual muscle test, and forced vital capacity defined as a percentage of normal values (FVC%). In the DMD group all variables measured deteriorated and there was a direct correlation between them. In the SMA group only muscle strength and FVC% deteriorated and there was no close relation between the variables measured. In the DMD group, 16 participants had cardiorespiratory clinical events leading to death in five cases. In the SMA group only four participants had respiratory clinical events, none leading to death. Although the participants with SMA had been extremely weak and non‐ambulatory since early childhood they were older and less exposed to life‐threatening events than the participants with DMD.