points because respiratory muscle training can cause an effect on these
outcomes as well as respiratory function. We found that respiratory
strength improvement may last up to 24 months and that FVC remained
stable during the study. No difference of dyspnea symptoms was observed
during the study. We showed that the increase of MIP and MEP
is very pronounced in the first year with a slow decrease in the second
year of treatment, especially with MEP. The initial benefit of increased
MEP can be attributed to different training effects. It is likely that during
exercise, expiratory muscles are also stimulated. In LOPD, the thorax exercise
allows for better expansion and mobility of the sternocostal joints
preventing their calcification and muscle hypoextensibility/contracture.
Some patients presents different MIP and MEP trends at the beginning
of this study, one possible explication is that MIP and MEP maneuvers
are technique dependent and this can in part explicate this numbers.
The early decrease in MEP is presumably because the training with
Threshold operates only on inspiratory muscles. In addition, the patients
remained at the same grade of autonomy measured by the modified
Gardner-Medwin-Walton scale. During the study no correlation
between the MIP values and the modified Gardner-Medwin-Walton
scale were observed. One of the major challenges encountered in this
study was the ability to assess the compliance of patients. Since it is a
rare disorder, patients usually have to travel to a specialized center in
order to be treated. In fact, only 1/8 patients were living in Trieste;
therefore, conducting interviews by telephone was the most appropriate
method to promote and evaluate training compliance. Adherence
to treatment may be negatively affected by the higher level of resistance
applied to the device, thus markedly increasing the intensity of work; it
may sometimes lead an effect that is difficult to maintain. The training
was explicated into the hospital and the patients were formed to repeat
the same exercise at home. We have no certitude of the compliance of
exercise at home. Therefore, patients have to be systematically encouraged
to continue the training protocol. Our data provide further insights
into the beneficial, cost effective, and safe results of inspiratory muscle
training in Pompe disease. Since this is a rare disease, it would be diffi-
cult to conduct controlled studies. We believe that respiratory muscle
training should be established early in the treatment of this infrequent
but disabling condition. Traditionally, excessively strenuous resistance
exercises have been discouraged in muscle disorders because of the potential
for exacerbating muscle lesion and degeneration. Studies evaluating
the effect of ERT in LOPD disease showed a favorable pattern of
response in muscle strength, including respiratory parameters, but further
studies are needed to confirm these and our data.