In which condition is the vital capacity reduced while the timed vital capacity (FEV 1.0 %) remains within normal limits?

Explanation

Scoliosis, a restrictive lung disease, leads to a decrease in vital capacity due to reduced chest wall expansion, but the FEV 1.0 % remains normal because airway obstruction is not present. In contrast, obstructive diseases like asthma and chronic bronchitis typically show a decreased FEV 1.0 %.