The Assessment of the Disablement
Process in Parkinson’s Disease
The Assessment of the Disablement Process in Parkinson’s Disease
Thesis Leiden University, November 16, 2005
ISBN:90 6464 4616
© 2005, M.Visser, except (parts of) the following chapters:
Chapter 2: Elsevier Science
Chapter 3: BMJ Journals
Chapter 5, 6 and 8: John Wiley & Sons, Ltd.
Chapter 7: Associated Professional Sleep Societies, LLC
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The Assessment of the Disablement
Process in Parkinson’s Disease
ter verkrijging van
de graad van Doctor aan de Universiteit Leiden,
op gezag van de Rector Magnificus Dr.D.D.Breimer,
hoogleraar in de faculteit der Wiskunde en
Natuurwetenschappen en die der Geneeskunde,
volgens besluit van het College voor Promoties
te verdedigen op woensdag 16 november 2005
klokke 14.15 uur
geboren te Amsterdam
Promotor: Prof. Dr. R.A.C. Roos
Co-promotores: Dr. J.J. van Hilten
Dr. Ir. A.M. Stiggelbout
Referent: Dr. P. Martinéz-Martin (Neuroepidemiology Unit, National Centre for
Epidemiology, Carlos III Institute of Health, Madrid, Spain)
Lid: Prof. Dr. F.G. Zitman
The studies described in this thesis were performed at the Department of Neurology of the
Leiden University Medical Center, Leiden, The Netherlands, and were financially supported
by the Netherlands Organization for Scientific Research (NWO, project no 0940-33-021) and
the Leiden University Medical Center.
Financial support for this thesis has been provided by NWO, Stichting het Remmert Adriaan
Laan fonds, the Dutch Parkinson’s Disease Society (Parkinson Patiënten Vereniging),
Boehringer Ingelheim, Novartis Pharma B.V., GlaxoSmithKline, Medtronic B.V. and
Voor mijn ouders
1. Introduction: The disablement process in Parkinson’s disease 9
2. Clinical tests for the evaluation of postural instability in patients 15
with Parkinson’s disease
M. Visser, J. Marinus, B.R. Bloem, H. Kisjes, B.M. van den Berg,
J.J. van Hilten.
Arch Phys Med Rehabil 2003;84:1669-74
3. A short scale for the assessment of motor impairments and disabilities 33
in Parkinson’s disease: the SPES/SCOPA.
J. Marinus, M. Visser, A.M. Stiggelbout, J.M. Rabey,
P. Martinez-Martin, U. Bonuccelli, P.H. Kraus, J.J. van Hilten
J Neurol Neurosurg Psychiatry 2004;75:388-95
4. Responsiveness of impairments and disabilities in Parkinson’s disease 55
M.Visser, J. Marinus, A.M. Stiggelbout, J.J. van Hilten.
submitted for publication
5. Assessment of autonomic dysfunction in Parkinson’s disease: 67
M. Visser, J. Marinus, A.M. Stiggelbout, J.J. van Hilten.
Mov Disord 2004;19:1306-12.
6. The reliability and validity of the Beck Depresion Inventory in 83
M. Visser, A. Leentjens, J. Marinus, A.M. Stiggelbout, J.J. van Hilten.
Mov Disord in press
7. Assessment of Sleep and Sleepiness in Parkinson’s disease 95
J. Marinus, M. Visser, J.J. van Hilten, G.J. Lammers,
8. Assessing comorbidity in patients with Parkinson’s disease 115
M. Visser, J. Marinus, J.J. van Hilten, R.G.B. Schipper,
Mov Disord 2004;19:824-8
9. Summary and conclusions 127
10. Samenvatting en conclusies 137
List of Abbreviations 147
List of Publications 149
Curriculum Vitae 151
The Disablement Process in
Parkinson’s disease (PD) is a common neurodegenerative disease, affecting
approximately 1.8% of the population over the age of 65.1 The prevalence of PD increases
with age; it rises to 2.6% of the population between 85-89 years of age. James Parkinson
described the disease called “shaking palsy (paralysis agitans)” for the first time in 1817.2 The
main clinical features of PD are motor symptoms such as, bradykinesia, rigidity, resting tremor
and postural instability, which are related to the degeneration of nigrostriatal dopaminergic
neurons. The neuropathological hallmark of PD is the presence of lewy bodies: distinctive
neuronal inclusions that are mainly composed of structurally altered neurofilaments.3 The
diagnoses of possible and probable PD are based on the presence of clinical motor features,
however neuropathological confirmation is required for the diagnosis of definite PD.4 The
pathogenesis of PD is currently unknown, but both genetic susceptibility and environmental
factors (e.g., smoking, pesticide exposure) appear to play a role in the disease process.5-8 For
a long time the main clinical focus in PD has been on the motor features, however, there is
increasing recognition that the clinical spectrum of PD is more extensive, also including non-
motor features such as cognitive dysfunction,9 depression,10 sleep disturbances,11 autonomic
disturbances,12 pain,13 and motor14 and psychiatric complications of therapy.15 Furthermore,
within the PD population, there is marked clinical heterogeneity,16 which may suggest that
subgroups of PD exist that not only differ in the presence and severity of different impairments,
but may also vary with respect to the rate of disease progression. Awareness of the whole
spectrum of PD may improve if a conceptual model that describes the different levels of PD
The Disablement process
The disablement process is a sociomedical model that describes the pathway from
pathology to disability via impairments and functional limitations, and incorporates intra and
extra-individual factors that speed up or slow down the rate of disablement.17 Impairments
are defined as dysfunctions and significant structural abnormalities in specific body systems,
functional limitations are restrictions in performing basic physical and mental actions, and
disability is the experienced difficulty doing activities of daily life. This conceptual framework
is based on: (1) the scheme on disability by Nagi18 and (2) the International Classification of
Impairments, Disabilities and Handicap (ICIDH) by the World Health Organization.19 The
disablement process focuses on the consequences of disease rather than on disease etiology
and forms a framework for research design or patient management.
The disablement process may be used to describe the various domains at the
impairment and disability level, and global outcomes of health that may be affected by PD.
Figure 1 describes the disablement process in PD. At the impairment level the model includes
cognitive dysfunction, mood disturbances, motor dysfunction, autonomic dysfunction, pain,
sleep disruption/excessive daytime sleepiness (EDS), and motor and psychiatric complications
of therapy. At the level of disability, difficulties with ADL and psychosocial functioning are
incorporated into the model. The global outcomes of health include global health, utility and
costs. This model summarizes the complete spectrum of the disease at a glance and can improve
our understanding of the disease and the influence of personal and environmental factors.
Figure 1: The disablement process in PD
physical / ADL
sleep / EDS
extra individual factors
mastery / self-efficacy
INTRODUCTION: THE DISABLEMENT PROCESS IN PARKINSON’S DISEASE
Assessments in PD
The evaluation of the functioning of patients with PD on the different domains
of the disablement process requires a broad range of assessment scales. Although several
assessment scales have been developed specifically for PD, the main focus has always been
on motor impairments and activities of daily living (ADL), leaving out aspects such as,
cognition, depression, sleep, or autonomic dysfunction. Furthermore, the majority of available
rating scales has clinimetric shortcomings, or has not been subjected to clinimetric testing.20
A clinimetric sound assessment scale should fulfill the following criteria: a high standard
of reliability (test-retest reliability inter-rater reliability and internal consistency), a high
standard of validity (content validity, factorial validity, criterion validity, and discriminant
validity) and responsiveness (sensitivity to change).
Aims of this thesis
In preparation for a longitudinal study on the disablement process in PD, the aim
was to construct a disease-specific model of the disablement process, encompassing all
relevant domains in PD on the levels of impairments, disabilities, global outcomes and intra
and extra-individual factors that act on this pathway. This model was constructed on the basis
of literature review and of consulting experts in the field of PD.
Specific attention has been given to comorbidity as an intra-individual factor. The
prevalence of both PD and comorbidity increase with advancing age and therefore many
patients with PD will also suffer from other diseases related to old age (e.g. diabetes,
osteoporosis).21;22 The presence of comorbid diseases will have consequences for disability,
substantially adding to the disease burden, and this information should therefore be included
in the disablement process.22
Following the construction of the model, for each PD domain an assessment scale
was selected or developed. This project was called the SCales for Outcomes in PArkinson’s
disease (SCOPA). Prerequisites for the assessment scales were good reliability, validity,
and (potential) responsiveness. Furthermore, the design of the longitudinal project was that
PD patients would be evaluated for all these domains simultaneously. Therefore, additional
requirements for the assessment scales were that they were: (1) short, (2) practical, not
requiring sophisticated measurement instruments, and (3) either self-assessed or could be
used by research personnel without demanding extensive training. A standard procedure was
followed for assigning the assessment scales. If a clinimetrically sound scale was available
for a PD domain, this scale was incorporated into the model. If a scale was available but the
clinimetric properties of the scale in a PD population were unknown, this scale was evaluated
in PD. If no scale was available for a domain, then this scale was developed and evaluated. In
this thesis, the clinimetric evaluation and development of PD specific assessment scales on
the levels of impairments, disability and intra-individual factors is described.
INTRODUCTION: THE DISABLEMENT PROCESS IN PARKINSON’S DISEASE
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Lobo A, Martinez-Lage J, Trenkwalder C, Hofman A. Prevalence of Parkinson’s disease in
Europe: A collaborative study of population-based cohorts. Neurologic Diseases in the Elderly
Research Group. Neurology 2000;54:S21-S23.
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3. Gibb WR, Lees AJ. The relevance of the Lewy body to the pathogenesis of idiopathic Parkinson’s
disease. J Neurol Neurosurg Psychiatry 1988;51:745-52.
4. Gelb DJ, Oliver E, Gilman S. Diagnostic criteria for Parkinson disease. Arch Neurol 1999;56:33-
5. Mouradian MM. Recent advances in the genetics and pathogenesis of Parkinson disease.
6. Dekker MC, Bonifati V, van Duijn CM. Parkinson’s disease: piecing together a genetic jigsaw.
7. Di Monte DA. The environment and Parkinson’s disease: is the nigrostriatal system preferentially
targeted by neurotoxins? Lancet Neurol. 2003;2:531-8.
8. Warner TT, Schapira AH. Genetic and environmental factors in the cause of Parkinson’s disease.
Ann.Neurol. 2003;53 Suppl 3:S16-S23.
9. Bosboom JL, Stoffers D, Wolters EC. Cognitive dysfunction and dementia in Parkinson’s
disease. J Neural Transm 2004;111:1303-15.
10. Brooks DJ, Doder M. Depression in Parkinson’s disease. Curr Opin Neurol 2001;14:465-70.
11. Tandberg E, Larsen JP, Karlsen K. A community-based study of sleep disorders in patients with
Parkinson’s disease. Mov Disord 1998;13:895-9.
12. Martignoni E, Pacchetti C, Godi L, Micieli G, Nappi G. Autonomic disorders in Parkinson’s
disease. J Neural Transm Suppl 1995;45:11-9.
13. Ford B. Pain in Parkinson’s disease. Clin Neurosci 1998;5:63-72.
14. Schrag A, Quinn N. Dyskinesias and motor fluctuations in Parkinson’s disease: A community-
based study. Brain 2000;123:2297-305.
15. Aarsland D, Larsen JP, Cummins JL, Laake K. Prevalence and clinical correlates of psychotic
symptoms in Parkinson disease: a community-based study. Arch Neurol 1999;56:595-601.
16. Foltynie T, Brayne C, Barker RA. The heterogeneity of idiopathic Parkinson’s disease. J Neurol
17. Verbrugge LM, Jette AM. The Disablement Process. Soc Sci Med 1994;38:1-14.
18. Nagi SZ. Some conceptual issues in disability and rehabilitation. In: Sussman MB, ed. Sociology
and rehabilitation. Washington D.C.: American Sociological Association 1965: 100-13.
19. World Health Organization. International Classification of impairments, disabilities, and
handicaps: a manual of classifications relating to the consequences of diseases. Geneva: World
Health Organization, 1980.
20. Ramaker C, Marinus J, Stiggelbout AM, van Hilten BJ. Systematic evaluation of rating scales
for impairment and disability in Parkinson’s disease. Mov Disord 2002;17:867-76.
21. Guralnik JM. Assessing the impact of comorbidity in the older population. Ann Epidemiol
22. Verbrugge LM, Lepkowski JM, Imanaka Y. Comorbidity and its impact on disability. Milbank
15 Download full-text
Bastiaan R. Bloem²
Barbara M. van den Berg¹
Jacobus J. van Hilten¹
Departments of Neurology, ¹Leiden University Medical Center, Leiden and
²University Medical Center St Radboud, Nijmegen, The Netherlands
Published in Archives of Physical Medicine and Rehabilitation 2003;84:1669-1674
Clinical Tests for the Evaluation of Postural
Instability in Patients with Parkinson’s