Figure 1
![Figure 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1752-1947-6-42/MediaObjects/13256_2011_Article_2016_Fig1_HTML.jpg)
Ratios regarding pulmonary function tests, hours using non-invasive ventilation (NIV) and months of evolution. Panel A - Vital capacity (VC) in a percentage of the normal values, PaCO2 in mmHg and hours of NIV use. Panel B - Maximal static respiratory pressures at the mouth: maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) are expressed as a percentage of the normal values. Tests show a worsening of the pulmonary function, maintaining normocapnia. The NIV duration was increased to full-time NIV for 16 months before death. During the last few months, VC was non-measurable, and MIP and MEP were zero or non-measurable.