The main findings of this longitudinal community-based study were that untreated patients with parkinsonism who subsequently received the diagnosis of PD, experienced at their first visit to a neurological centre decrease in ADL abilities and in their life quality, compared to age-matched healthy subjects. Additionally, within the various subgroups of PD, patients with the PIGD subtype were early on far worse both clinically and in their ADL and QoL, than patients with TD subtype. Finally, another incidental finding was that, in this community-based study, PD was almost equally distributed between men and women.
Patients with TD type of disease had been aware of symptoms and signs of the disease for a longer duration before seeking medical attention, compared to patients in the PIGD and IND groups. The reason could be that tremor is a more distinct symptom and therefore the time of onset is easier to remember.
Activities of daily living
This study showed significant differences foremost between the PIGD and the TD groups of patients, as well as between the PIGD and the HC groups, with respect to both P- and I-ADL, showing more difficulties for patients with a PIGD type of disease, (Fig. 1A, B and Table 2).
In 50% of the P-ADL actions, patients with PIGD type of disease showed significantly poorer results compared to HC, whereas the TD group only differed in four actions i.e., ‘eating’, ‘cutting food’, ‘writing’ and ‘walk in neighbourhood’ compared to the HC (Fig. 1A and Table 2). In I-ADL there were significant differences in 75% of actions, indicating that in more complex ADL-activities such as home maintenance, shopping and transportation, the differences between patients and HC were more prominent (Fig. 1B and Table 2). These activities are known to involve interaction with others and with the environment (20).
Writing difficulty has been described as a sign of the disease that could be detected before the diagnosis (21). According to an experimental study by Ponsen et al. (22) patients with newly diagnosed and untreated PD, demonstrated impairment in performing tasks such as writing and concluded that this kind of tasks ‘is a very early characteristic of PD’. These results are confirmed in our study by the patients’ own rating of their ability to write.
Mobility in general and particularly gait is affected in PD (23), through the decline of gross motor skills (24) (akinesia) and also the eventual effect of cognitive changes (executive function) (25). Our study shows that in addition to ‘walking in neighbourhood’ also ‘transfer in bed’, and ‘walking stairs’ were the first aspects of mobility (transfer) to be affected at this early stage of disease. The reason that walking outside is affected, but not the ability to move around inside, could be explained by the home environment being more familiar and predictable than walking outside (26).
In a recent clinical experimental study by Doan et al. (27) early PD patients compared to age matched controls showed, despite a unilateral disease, difficulties in performing bilateral reach-to-eat tasks. This was confirmed in our PIGD and TD patients by showing significant differences compared to HC in the actions ‘eating’ and ‘cutting food’.
Among patients with PIGD type of disease the ability to dress and undress is reduced compared to both the TD group and the HC. Dressing is a daily goal-directed activity requiring good balance, bimanual coordination, and both gross and fine motor skills. Difficulties in dressing have been shown to be one important factors impacting on patients’ quality of life (28).
I-ADL consists of more complex and more demanding activities, and a prerequisite for individuals to be able to participate in society. Here too, PIGD patients had more difficulties than the TD group of patients in most I-ADL activities. This is in accordance with the study of Muslimovic et al. (29) who found that axial impairment contributed most to disability in a sample with mild to moderate PD. Furthermore, I-ADL puts further constraints on attentional load, which is considered to be a key constraint to motor performance in PD (30).
Despite the fact that the patients and specifically patients with PIGD type of disease displayed significantly worse scores than healthy subjects on both P- and I-ADL, the impact of PD on daily activities at this early stage of the disease was rather mild, and no action in P or I-ADL reached the level of being effort demanding except ‘pedicuring’ for patients with PIGD and IND type of disease. This action requires balance, coordination and also manual dexterity.
According to Fried et al. (31) this stage of limitation in daily activities may be defined as pre or subclinical state of disability, and according to Lilienfeld & Lilienfeld (32) this preclinical disability is characterized as ‘early functional limitations’ before it is clinically obvious or efficiently hinders daily activities. It may be that some of the early limitations in ADL are surmounted by the use of compensatory strategies implying e.g. adjusted expectations and acceptance of slower or less frequent performance, or redefining roles so that the action is no longer necessary (31). By assessing patients at this early stage of disease it is possible to understand the process leading to activity limitations and disability. This knowledge may guide rehabilitation teams in finding ‘critical’ points, where rehabilitative steps can be used to prevent and delay activity limitations and disability by implementing training programs early on, before the patients reach more advanced disease stages affecting not only movements but also cognition, and thus lose abilities to benefit fully from rehabilitation (33, 34).
Quality of life
In advanced cases of PD many factors may obviously affect QoL, not least treatment related factors such as motor fluctuations (35, 36). Here we show factors of importance of QoL prior to any treatment. On the PDQ 39 summary index, the PIGD group showed worse results than the other groups. ‘Mobility’, ‘ADL’, ‘communication’ and ‘bodily discomfort’ were the aspects where PIGD patients scored worse, which is in agreement with findings by Muslimovic et al. (29) and Schrag et al. (37) in that axial impairment is strongly associated with decrease in QoL. This similarity between our findings and those of the two quoted studies above is the more interesting, since our patients were rated at first visit, after a mean symptom duration of 1.6 year, while the patients of the two referred studies had a mean disease duration of 3.3 and 5.3 years, respectively.
On the SF 36 scale the PIGD group showed worse values compared to the two other subgroups, and compared to HC. The merit of using this non-disease specific QoL scale is that patients can be compared to healthy controls. The largest discrepancy between PIGD patients and HC was in the domain of ‘role physical’ which corroborates the findings of the ADL taxonomy, and reflects the early disability and functional limitations of patients with dominant axial symptoms. The fact that PIGD patients, at this early stage, exhibited also higher values on the MADRS than healthy subjects –although they still did not fulfil criteria for diagnosis of depression– may also have impacted on their quality of life, as described by Schrag et al. (37).
In conclusion, this is the first study to our knowledge, which in an untreated community-based population with Parkinson’s disease, shows that already at first visit to a neurological centre; patients exhibit restrictions in ADL and QoL. Among these patients, those affected most both at the level of activity and of participation, as well as in quality of life, are patients with axial symptoms. These points to the need for an early, individualized, and differentiated rehabilitation program for patients with newly diagnosed PD.