Chest
Volume 115, Issue 6, June 1999, Pages 1546-1552
Journal home page for Chest

Clinical Investigations
Neuromuscular Disease
Reliability of Maximal Respiratory Pressures in Multiple Sclerosis

https://doi.org/10.1378/chest.115.6.1546Get rights and content

Objective

To assess the reliability of maximal inspiratory pressure (Pimax) and maximal expiratory pressure (Pemax) in subjects with multiple sclerosis (MS) and healthy control subjects by identifying the number of testing sessions and the number of measurements needed in a single testing session to obtain consistent, reproducible results.

Design

A descriptive, comparative design with repeated measures was used.

Setting

Four sets of 10 Pimax and 10 Pemax measurements were obtained over a 4-week period from MS subjects in their homes. The same measurements were obtained from healthy control subjects in a private setting.

Subjects

Seventy-two MS patients and 61 healthy control subjects participated in the study.

Measurement

Pimax and Pemax values were obtained by using previously published methods.

Results

Mean Pemax and Pimax values for MS patients differed over the first three of the four testing sessions. By contrast, mean Pemax and Pimax values for healthy control subjects differed only when the first session values were compared with values from the last three sessions. For MS patients, Pemax and Pimax increased between the first and 10th trial during the first testing session, but not during the subsequent three sessions.

Conclusions

The results of this study suggest that several practice sessions should be provided in order to obtain reliable Pemax and Pimax values in persons with MS. At least one practice session should be provided for healthy control subjects before identifying a baseline.

Section snippets

Materials and Methods

This descriptive, comparative study with repeated measures was designed to determine the number of testing sessions and number of measurements within a testing session needed by patients with MS and healthy control subjects to obtain reproducible results.

Number of Testing Sessions

The means of 10 Pemax and 10 Pimax values of the four separate testing sessions were calculated for the MS patient group and the healthy control group (Table 2). Mean Pemax values in MS patients differed by testing session [F (3, 71) = 15.513; p = 0.0001] with the following specific differences detected by post-hoc analyses: session 1 vs 3, 1 vs 4, 2 vs 3, and 2 vs 4. Mean Pimax values in MS patients also differed by testing session [F(3, 71) = 24.91; p = 0.0001]. Specific differences were

Number of Testing Sessions

The findings of this study indicate that two practice sessions are required by MS patients and one practice session by healthy control subjects to obtain consistent Pimax and Pemax values by the third and the second testing sessions, respectively. These findings suggest a learning effect and are consistent with those of other researchers who have studied healthy control subjects and patients with pulmonary disease. They also suggest that learning takes longer in persons with MS than in healthy

Conclusion

Accurate periodic Pimax and Pemax measurements are useful in identifying both the need for interventions directed toward respiratory muscle weakness in impaired MS subjects who are unable to participate in physical activity and strategies to preserve respiratory muscle strength in persons with MS. The results of this study suggest a learning effect as a factor that needs to be considered in Pimax and Pemax measurement. Failure to take this learning effect into account may result in inaccurate

References (22)

  • SH Wilson et al.

    Predicted normal values for maximal respiratory pressures in Caucasian adults and children

    Thorax

    (1984)
  • Cited by (0)

    Supported by National Institute of Nursing Research, National Institutes of Health grant R15NR02763–01.

    View full text