Canadian researchers used two tools designed to assess bulbar function in adults with SMN1-related proximal spinal muscular atrophy (SMA):
- 15 adults with SMA took part in this 12-month validation study,
- which measured maximal phonation time (MPT) and the S/Z ratio, assessing the specific phonation time for the phonemes ‘s’ and ‘z’,
- whilst correlating these data with other outcome measures such as vital capacity,
- both tests are very simple to administer and correlate well with bulbar function, as has already been demonstrated in comparable degenerative conditions,
- the limitation of the MPT lies in its low sensitivity to change.
This approach is particularly well-suited to centres that do not have sophisticated equipment for assessing bulbar function, particularly in patients with SMA
