Functional Physical Rehabilitation and Self-Assessment of Physical Activity in Parkinson’s Disease

Introduction

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms such as tremor, rigidity, bradykinesia, and postural instability. The primary pathophysiology of PD involves the gradual loss of dopaminergic neurons in the pars compacta of the substantia nigra, leading to a significant decrease in striatal dopamine levels and disrupting basal ganglia circuits responsible for motor control [1,2]. These impairments often cause decreased functional independence and lower quality of life [3]. In addition to motor symptoms, PD is commonly associated with non-motor symptoms like cognitive decline, depression, fatigue, and autonomic dysfunction [4], which further increase the disease burden and complicate treatment [5].

In this context, physical activity (PA) has become a vital therapeutic component for managing both motor and non-motor symptoms of PD [6]. Regular PA can increase neuroplasticity, delay symptom progression, improve gait and balance, and support cognitive and emotional well-being [7]. Studies also suggest that sustained PA can have disease-modifying effects by increasing cerebral blood flow, reducing neuroinflammation, and enhancing dopaminergic function [7,8].

Given these benefits, various types of physical rehabilitation have been introduced to support patients with PD. Functional physical rehabilitation (FPR) is an approach that combines symptom-specific therapy with task-oriented training. It aligns with integrated clinical reasoning models that emphasize individualized, goal-directed, and functionally relevant interventions in neurologic physical therapy practice [9]. FPR addresses real-world functional deficits by blending motor reeducation with meaningful activities designed to enhance independence [10]. Its structured, flexible nature allows individuals to engage in rehabilitation that is both therapeutically effective and personally motivating [9].

Despite the central role of PA and rehabilitation in PD management, accurately measuring PA in this population remains a methodological challenge [11]. Self-report instruments, such as questionnaires or activity diaries, are commonly used [12]. However, these tools are vulnerable to several limitations, including recall bias, social desirability bias, and difficulties in understanding or interpreting the types and intensities of activity [13]. In patients with PD, these issues are further worsened by disease-specific cognitive deficits, such as impaired executive functioning, attention, and memory, which can decrease the reliability of retrospective self-assessment [13].

Objective measurement methods, most notably accelerometers, provide quantifiable and precisely timed data on movement intensity, frequency, and duration. Devices such as triaxial accelerometers have demonstrated validity in measuring PA levels [14]. However, their effectiveness in clinical settings can be limited by patient non-compliance, discomfort during long-term wear, or difficulties in managing the equipment [13].

Emerging evidence shows that individuals with PD often either overestimate or underestimate their PA levels compared to objective measurements [13]. These differences can result from an altered perception of physical effort, limited awareness of what counts as PA (such as walking or household chores), or difficulty accurately recalling routine behaviors [15]. Such measurement bias can obscure the true effectiveness of interventions and complicate treatment planning.

This gap between self-reported and objectively measured PA is clinically important. Accurate PA assessment is key for evaluating treatment results, tailoring interventions, and encouraging long-term behavioral adherence [16]. Although subjective and objective methods are frequently used, few studies have directly compared them in structured rehabilitation programs. There is limited evidence on whether participation in functional rehabilitation influences physical performance and awareness and accuracy of activity self-assessment.

The discrepancy between perceived and actual PA in people with PD is a complex issue with many contributing factors. Therefore, we compared self-reported and objective PA levels in people with PD within the context of participation in FPR.

Material and Methods

The study included 47 patients with idiopathic PD, according to MDS Clinical Diagnostic Criteria for Parkinson’s Disease [17], aged 64.37±7.12 years, with disease duration 6.29±4.02 year, in stages II and III of the disease according to the Hoehn and Yahr scale [18]. To determine the clinical status of patients, the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) was applied [19].

Inclusion criteria were: diagnosis of Parkinson’s disease based on the MDS Clinical Diagnostic Criteria for Parkinson’s Disease, stage 2 or 3 of the disease according to the Hoehn and Yahr scale, Mini-Mental State Examination score of ≥24 [20], Beck Depression Inventory score <10 indicating no depression [21], no coexisting neurodegenerative diseases, and no contraindications for physical exercise.

Exclusion criteria were: concomitant neurodegenerative diseases, concomitant diseases with reduced exercise tolerance, and earlier involvement in physical rehabilitation classes.

Participants were evaluated by a neurologist, who performed a clinical interview, neurological exam, and reviewed medical records to rule out other neurodegenerative disorders or comorbidities that could limit physical activity. Only those with no medical contraindications to exercise were included in the study.

The patients volunteered to participate in the study and were recruited from Parkinson’s disease associations in the Silesian region of Poland. The study was performed following the ethical principles outlined in the Declaration of Helsinki. Approval was obtained from the Bioethics Committee of the Academy of Physical Education in Katowice (approval no. 30/2017). All participants were thoroughly informed about the study’s goals and procedures and provided written informed consent before participating. The purposive sampling technique was used as an experimental method to observe causal relationships and dependencies. Participants were randomly assigned to 2 groups: those participating in the FPR program (Group A) and those not participating (Group B).

The simple randomization process was carried out by an independent assistant who was not involved in the study procedures and was blinded to the study objectives. To maintain allocation concealment, a standard procedure was followed, with random group assignment performed after participant enrollment. Clinical assessments were conducted by evaluators blinded to group allocation. Statistical analyses were carried out by an independent researcher who was not involved in participant recruitment or the intervention and remained unaware of group assignments. Figure 1 presents a flow chart of how participants were recruited.

The study implemented a rehabilitation program aimed at improving functional independence and quality of life in individuals with PD. The main principles of the program were based on combining therapy targeting motor symptoms with task-oriented therapy. Each exercise was functionally justified and specifically designed to assist patients in coping with everyday activities. Additionally, strategies for managing tremor were implemented [22]. The rehabilitation process was adapted to individual patient needs and capabilities, focusing on the most critical movement-related issues, such as muscle rigidity, bradykinesia, postural reflex disorders, and tremors.

Participants in the FPR program attended sessions twice a week for 60 minutes on non-consecutive days over 9 months following group allocation as part of the study intervention. The sessions were conducted by a physiotherapist who specializes in rehabilitation for people with PD. They were held in groups of 8 participants. Along with the lead physiotherapist, trained assistants also observed participants’ heart rates and effort levels during sessions. Each session included 3 parts: a warm-up, a main portion, and a cool-down.

Warm-up (15 minutes) involved exercises targeting the cervical spine, torso rotations, upper-limb exercises including alternating flexion-extension and simultaneous abduction-adduction movements, and lower-limb exercises performed while supported by the side of a chair, including flexion-extension, abduction-adduction, and ankle dorsiflexion-plantarflexion movements. All exercises were done within each participant’s maximum personal range of motion.

The main part (30 minutes) consisted of simple and complex movement patterns aimed at improving motor skill fluidity and functional capability in everyday tasks. The exercises included activities such as independent turning and getting out of bed or a chair, dressing, putting on and lacing shoes, ascending and descending stairs, crossing thresholds of varying heights, moving outdoors on different surfaces, and exercises using external cueing signals.

Cool-down (15 minutes) included relaxation exercises designed to calm the body, such as breathing exercises, static stretching, and proprioception exercises performed with eyes open and closed.

The used sets of exercises were worked out by the authors based on the literature [10,23]. The patients in group B did not participate in the rehabilitation sessions.

The International Physical Activity Questionnaire (IPAQ) [24,25] and the Actigraph GT3X+triaxial accelerometer were used to measure weekly physical activity (AC) [26]. The assessment of PA was conducted using a device monitoring weekly physical activity, which recorded accelerations in the sagittal, frontal, and transverse planes. The device was worn by the participants for 7 consecutive days at hip level and removed only during sleep and water-related activities. According to the PA assessment guidelines, measurements were conducted in October and March [24,25,27].

The accelerometer-recorded data were subjected to statistical analysis using ActiLife 5.10.0 software, which allowed for obtaining PA parameters such as the duration of physical efforts of low, moderate, and high intensity. The following thresholds of recorded accelerations (signals) per minute (counts per minute – cpm) were used for this purpose: 200–2689 cpm for low-intensity PA, 2690–6166 cpm for moderate-intensity PA, and 6167 cpm and above for high-intensity PA [27].

The respondents completed an IPAQ questionnaire while reviewing data from the accelerometer to assess their self-reported PA. They were asked to evaluate their PA from the previous week when they wore the accelerometer. A short version of the IPAQ questionnaire was used, containing questions about the number of days they engaged in activities of various intensity levels. Based on their responses, the volume of PA was categorized into 3 intensity zones: low (walking), moderate, and high (vigorous). Using the collected data on the frequency, intensity, and duration of PA during the day, the weekly volume of PA was determined for each intensity zone. Activity intensity was measured using metabolic equivalent of task (MET) values: 8.0 MET for vigorous activity (PA1), 4.0 MET for moderate activity (PA2), and 3.3 MET for low activity, such as walking (PA3). The calculation procedure involved multiplying each intensity zone’s number of days, duration, and MET values separately. The total weekly physical activity (WPA) was determined by summing up its level in the 3 intensity zones (MET-min/week) [28]. The calculations were made separately for the data obtained from the questionnaire and the Actigraph.

The obtained results were compiled and prepared following statistical rules. Basic descriptive statistics were calculated, and the normal distribution was assessed using the Kolmogorov-Smirnov test. The Kolmogorov-Smirnov test was employed to verify the normality of data distribution due to its effectiveness and robustness in small- and medium-sized samples, as was the case in this study (n=47). To assess the significance of differences, the t test was used for independent samples.

In addition, the frequency and volume of daily PA in the 3 intensity zones within the group were compared by calculating the absolute and relative differences. The relative difference was calculated by subtracting the objectively measured PA value from the self-reported PA value, dividing the result by the objectively measured value, and multiplying it by 100. This calculation enabled comparison of the discrepancies between the 2 measurement methods within groups and intensity zones.

Results

Before conducting the analysis, the 2 groups were compared based on age, disease duration, and MDS-UPDRS score (Table 1), showing no statistically significant differences between the groups in most of the features analyzed. Part II of the MDS-UPDRS scale results found a statistically significant difference.

A comparison of self-reported and objectively measured weekly PA revealed that participants from both groups significantly overestimated their PA (Table 2). Specifically, patients in Group A overestimated their weekly PA by 8.61% (p=0.002), while patients in Group B showed a much greater overestimation of 56.70% (p=0.003). These findings indicate that participation in the FPR program (Group A) was associated with a smaller discrepancy between subjective and objective measures of PA compared to patients who did not participate (Group B).

According to the methodology used in this study, weekly physical activity (WPA) refers to the total amount of PA across each intensity zone. Consequently, further analysis was performed separately for each intensity zone (Figure 2). In both groups, low-intensity PA dominated. Group A participants overestimated their PA compared to objective measurements in all intensity zones. Specifically, their self-reported PA was higher by 19.50% in the high-intensity zone (P<0.02), by 10.52% in the moderate-intensity zone (P<0.01), and by 7.35% in the low-intensity zone (P>0.05). The overestimations observed in the high- and moderate-intensity zones were statistically significant.

In Group B, similarly to Group A, participants significantly overestimated their PA compared to the objective measurements across all intensity zones. The greatest overestimation was observed in the high-intensity zone (by 250%; P<0.001), followed by the moderate-intensity zone (by 90.66%; P<0.01) and the low-intensity zone (by 48.32%; P<0.002). All these differences were statistically significant, indicating that participants not participating in the FPR program had considerable difficulty accurately assessing their PA levels.

As the PA level in individual zones is a product of the number of days at a given intensity and the duration of effort, these parameters were analyzed (Table 3).

The analysis of the frequency and duration of daily PA across the 3 intensity zones revealed that in Group A, significant differences between self-reported and objectively measured PA were observed for both parameters (frequency and duration) in the high-intensity zone (P<0.01 and P<0.001, respectively). In the moderate- and low-intensity zones, only differences in duration were statistically significant (P<0.02 and P<0.01, respectively), while differences in frequency were not significant (P>0.05).

In Group B, statistically significant differences were found for the duration of PA in all intensity zones (high, moderate, and low; P<0.04, P<0.01, and P<0.01, respectively). Significant differences in frequency were observed only in moderate- (P<0.01) and low-intensity zones (P<0.01), whereas differences in frequency in the high-intensity zone were not significant (P>0.05). These findings confirm a systematic overestimation of PA duration and partly frequency among participants, particularly evident in Group B, which was not involved in the FPR program.

Discussion

STUDY LIMITATIONS:

This study has several limitations. First, the sample size was relatively small, and the population was limited to patients in Hoehn and Yahr stages II–III with no significant cognitive impairment. Therefore, generalizability to other stages or individuals with cognitive decline is limited. Second, the control group did not receive any alternative intervention, raising ethical and interpretive concerns. Future studies should compare different forms of physical activity interventions to better isolate the effects of rehabilitation structure versus general activity. Third, the reliance on a single week of accelerometer data may not fully represent habitual activity patterns. Lastly, although participants were randomly assigned, full blinding was not feasible during intervention, which may have introduced potential bias.

FUTURE DIRECTIONS AND CLINICAL IMPLICATIONS:

Further research is needed to identify the primary factors contributing to the discrepancies between subjective and objective measures of physical activity in individuals with Parkinson’s disease. Studies that account for physical fitness level, disease severity, and cognitive status may offer deeper insight into the interaction between perceived and actual activity and its influence on motor and non-motor symptoms. In particular, future studies should explore whether improvements in self-assessment accuracy are sustained over time and how they relate to treatment adherence, clinical outcomes, and long-term behavioral change. Investigating the interplay between physical fitness, self-efficacy, and PA perception in larger and more diverse PD populations, including individuals with mild cognitive impairment, would also be highly valuable.

The present findings suggest that structured interventions such as functional physical training not only increase physical activity levels but may also improve individuals’ ability to accurately assess their performance. These results carry meaningful clinical implications. Incorporating structured, task-specific movement therapies into standard PD care could reduce overestimation bias and improve the precision of physical activity monitoring, which is essential for personalized treatment planning. In turn, this may enhance patient engagement, support better disease management, and contribute to improved functional outcomes. Future research should compare different types of physical activity interventions to better isolate the mechanisms responsible for improvements in self-perception and to optimize rehabilitation protocols in clinical practice.

Conclusions

The evaluation of physical activity levels can be a useful source of information for tracking disease progression, monitoring treatment efficacy, and assessing the effectiveness of rehabilitation programs. Our study revealed significant discrepancies between self-reported and objectively measured PA levels in individuals with PD, depending on their participation in FPR. The study results show that participation in functional physical rehabilitation improves the accuracy of self-assessment of physical activity levels.