[Maximum phonation time as a tool of screening respiratory muscle weakness in myopathic patients].
We examined the relation of maximum phonation time (MPT) and vital capacity (VC) and reviewed the usefulness of MPT as a respiratory function screening.


METHODS
18 healthy adult subjects (8 men and 10 women), and 32 myopathic patients (24 men and 8 women).


METHODS
MPT and VC were measured in sitting position. Six patients were tested with and without air stacking by glossopharyngeal respiration.


RESULTS
In healthy subjects, MPT was 29.9 +/- 11.8 seconds in men and 21.7 +/- 7.8 seconds in women. Second trials showed good reproducibility. The healthy group had no correlation between MPT and VC. The patient group showed a significant positive correlation between MPT and VC (r2= 0.25, p=0.003). All patients with MPT less than 15 seconds showed VC less than 1.5 l and %VC less than 50%. Air-stacking by glossopharyngeal respiration significantly increased the MPT.


CONCLUSIONS
MPT is a useful screening test for respiratory muscle weakness. The patients are easily aware of the effect of air-stacking by glossopharyngeal respiration.
Toyoda
Chizuko
C
Department of Neurology, Musashi Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-machi, Kodaira-shi, Tokyo 187-8551, Japan.
Ogawa
Masafumi
M
Oya
Yasushi
Y
Kawai
Mitsuru
M
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D018908:Muscle Weakness / Q000503:physiopathology*; D009135:Muscular Diseases / Q000175:diagnosis*; D010609:Pharyngeal Muscles / Q000503:physiopathology; D010699:Phonation; D012119:Respiration; D012132:Respiratory Muscles / Q000503:physiopathology*; D013147:Spirometry; D013995:Time; D014797:Vital Capacity