Patients that have spinal cord injuries at or above the twelfth thoracic level have paralysis in at least one respiratory muscle, due to some of them will eventually have respiratory failure of a restrictive pattern. Pulmonary function needs to be tested continually to evaluate respiratory function and measure the effectiveness of the respiratory rehabilitation program. However, pulmonary function tests that are currently available have some limitations, such as technical problems or problems in the patients position. As a result a more convenient method of measuring pulmonary function is necessary.

In this study we used fifteen subjects with spinal cord injuries at or above the twelfth thoracic level. We measured phonation time and pulmonary function, as well as examined if there are any correlations between the phonation time and the subscales of the pulmonary function test.

The results showed that phonation time has a high correlation with vital capacity (VC), inspiratory capacity (IC) and expiratory reserve volume (ERV) (p<0.01). Our findings also very highly correlate phonation time with forced expiratory volume over one second (FEV1), forced vital capacity (FVC), maximum voluntary ventilation (MVV) and peak expiratory flow (PEF) (p<0.005).

We have concluded from these results that phonation time is a useful method for the evaluation and following up to pulmonary function in the patients with spinal cord injuries.