Functioning and related determinants in patients with inflammatory and idiopathic polyneuropathy

The aim of the studies described in the thesis was to study the functioning of patients with CIDP, MMN, or CIAP, and the determinants of their functioning. Specific research questions were: 1. What are the functional health profiles of patients with different inflammatory polyneuropathies (CIDP and MMN), and do these profiles reveal relevant determinants that can be studied further? 2. How can these determinants be assessed, i.e., what type of clinimetric instruments could be of value in these populations? 3. What are the functional health profiles of patients with CIAP and MMN established with these instruments? 4. What other determinant(s) might influence the functioning of patients with CIAP? The functional health profiles of patients with CIDP and MMN were investigated in a cross-sectional study on the basis of the International Classification of Functioning, Disability and Health (ICF) framework of the World Health Organization. The problems patients experienced in daily life were used to identify specific determinants of functioning and appropriate performance-based instruments. It was clear that dexterity and walking ability could be determinants of the functioning of patients with polyneuropathy. Because there are no specific instruments to assess dexterity and walking ability in these patients, the Sequential Occupational Dexterity Assessment (SODA) and the modified Shuttle Walk Test (SWT) were chosen as potentially relevant tests. The SODA has earlier been shown to be a valid tool to assess dexterity in patients with rheumatoid arthritis. Because the SWT was originally developed to assess functional capacity in patients with chronic airway obstruction and heart failure, the test was validated for the assessment of walking ability in patients with CIAP and MMN. Subsequently, the functional health profiles of patients with CIAP and MMN were assessed with the SODA and validated SWT, with help of the ICF. Functional health profiles differed between the patient groups. In addition to the functional health profiles derived from our studies, clinical experience has shown that pain might also be a determinant of the functioning of patients with CIAP. However, little is known about specific aspects of pain and its association with health-related quality of life. The pain patients experience was investigated in detail, using the generic McGill Pain Questionnaire. In summary, functional health profiles were established for patients with CIDP, MMN, and CIAP, and relevant determinants and performance-based instruments were selected. Functional health profiles differed between the patient groups. These findings indicated that it is essential to use performance-based tests in order to be able to assess problematic activities in detail. Effective methods to assess the pain experienced by patients with CIAP, and to assess balance in patients with CIDP and CIAP, are needed. The validated SWT proved to be of value in all patient groups, providing broad insight into patients’ walking ability, and is a welcome new test for clinical use. However, the clinimetric properties of the SODA and SWT still have to be determined. Future studies have to be developed to tailor medical and rehabilitation therapy aimed at improving the functional health of patients with polyneuropathy.