Laura Peeters

General discussion |121 6 Measurement scales Also standardized clinical measures would be useful to gain insight in trunk capacity or performance and are generally more easily applicable in clinical practice. However, validated measures for trunk function are scarce. The motor function measure (MFM) and the Hammersmith functional motor scale include trunk function and are often used in DMD and SMA patients [20, 21]. However, both scores are influenced by upper or lower extremity function, which makes it difficult to examine trunk function by itself. For example, MFM item 9 is defined as follows: “the patient sits on a chair and stretches his/her arms forward and maintains this position for 5 seconds”. When he/she cannot stretch the arms forward for 5 seconds, the score is decreased by 1 point, however, this could be solely due to a limitation in UE function. So, scoring trunk function with these measures will only be appropriate if trunk function is worse than UE function. Based on the results of this thesis, this assumption is, at least for DMD patients, highly questionable. Additionally, scoring is often decreased when a patient uses compensatory trunk movements when moving the UE, where this could also be seen as good trunk function. A proper measurement scale should therefore have a domain focusing on trunk function alone, but also one domain combining trunk and UE movement, because this reflects daily life situations. The Trunk Control Measurement Scale (TCMS) can be a good starting point as a measure for DMD and SMA, but its validation is needed. The TCMS has been developed and validated for children with cerebral palsy (CP) with the purpose to score both roles of the trunk during seated activities as discussed in this thesis, namely to form a stable base of support (i.e. static sitting balance) and to constitute an actively moving body segment (i.e. dynamic sitting balance) [22]. The latter aspect is further divided in the TCMS into selective movement control (i.e. trunk movement only) and dynamic reaching (i.e. involvement of the UE). Being able to use the same measurement scale for different patient groups with impaired trunk function gives the opportunity to compare diseases and generalize treatment strategies where possible. Detail of measuring As pointed out in the general introduction, the trunk is a complex segment and therefore people should carefully decide on which level of detail they want to evaluate the trunk. The aim and patient population should be kept in mind when making such a decision. For clinical assessment of overall trunk function, considering the trunk as one segment could be sufficient for DMD and SMA patients, because our results showed that the contribution of individual trunk segments to overall trunk movement was comparable to HC. However, differences between trunk levels can be expected in patients with a scoliosis, CP or spinal cord injury [23]. Therefore, considering the trunk as a rigid segment might not be appropriate for these patient groups, as it