Effect of Abnormal Posture on Quality of Life in Patients with Parkinson ’ s Disease

Background: Relationship between abnormal posture and QOL of Parkinson's disease is not clear. Objectives: To clarify the association between quality of life (QOL) and abnormal posture in patients with Parkinson’s disease (PD) and examine which QOL dimensions are involved. Methods: This study retrospectively examined PD patients (n = 57) who had undergone outpatient rehabilitation between January and March 2014. Evaluation items were Modified Hoehn Yahr (H-Y) stage, Unified Parkinson’s Disease Rating Scale (UPDRS)-Part III score, Timed Up and Go test (TUG, 3-m walking) result, Parkinson’s Disease Questionnaire (PDQ)-39 score, and the angle of forward and lateral trunk flexion in the standing position. Statistical analysis was performed to reveal the relationship between the total PDQ-39 score and individual evaluation items and which QOL dimensions were affected by abnormal posture due to forward or lateral flexion. Results: A total of 38 PD patients (17 men, 21 women; mean age, 73.2 ± 8.6 years) were enrolled. Among the evaluation items, lateral flexion angle showed a significant correlation with the total PDQ-39 score (r = 0.422, P = 0.008). PDQ-39 dimensions showing an association with forward flexion were activities of daily living (ADL) (P = 0.002) and communication (P = 0.007), whereas ADL (P = 0.004), communication (P = 0.021), and social support (P = 0.029) were associated with lateral flexion. Mobility was not associated with forward or lateral flexion. Conclusion: The present findings revealed a correlation between lateral flexion and QOL in PD patients. Among the PDQ-39 dimensions, ADL and communication were associated with abnormal posture.


Introduction
Parkinson's disease (PD) is a progressive chronic disease with motor symptoms as the primary manifestations.The adjusted prevalence in one Japanese city was 166.8 in 2004 when calculated using the Japanese, and the adjusted crude incidence was 10.3 in 2004 when calculated using the population in this city in 1980 [1].We experienced the variability in clinical expression of PD and characterized pathologically by the loss of pigmented neurons in the substantial nigra zone compacta, the presence of Lewy bodies, and other pathologic changes [2].The main treatment goal for PD is to maintain quality of life (QOL) as long as possible.Schrag et al. reported depression, cognitive impairment, gait disorder, a history of falls, and impaired postural reflexes as factors influencing QOL in PD patients [3].According to the Global Parkinson's Disease Survey Steering Committee, bipolar disease, inability to perform activities of daily living (ADL), and gait disorder were factors adversely affecting QOL [4].As these reports show, many disease-related factors influence QOL in PD patients, and therefore, it is important to recognize and integrate clinical symptoms and patient complaints [5].In contrast, Hagell et al. [6] provided general support for the acceptability and reliability of the PDQ-39.However, there has been no report about whether and how abnormal posture impacts QOL in PD patients.
As reported by James Parkinson in An essay on shaking palsy [7], abnormal posture has been known as a clinical manifestation of PD for a long time.Even today, abnormal posture remains the most difficult symptom to treat because it involves multiple background pathologies such as dystonia, rigidity, and proprioceptive dysfunction [8].It is also unclear how abnormal posture affects QOL and everyday life of PD patients.Therefore, to select appropriate treatment strategies and goals, we conduct a retrospective study to clarify whether abnormal posture affects QOL in PD patients, how it affects them, and which QOL dimensions are affected.In the present study, two body angles, fore-bent and lateral-bent angles were surveyed in PD patients.

Materials and Methods
Subjects were selected from a group of 57 PD patients who had undergone outpatient rehabilitation between January and March 2014 based on the following inclusion criteria: 1) patients were judged by their neurologist to be suitable for rehabilitation; and 2) consented before undergoing evaluation of the severity of PD and the outcome of rehabilitation.Evaluation data in patient medical records were retrospectively analyzed.The indications for rehabilitation were: 1) loss of motor function that was not caused by disuse syndrome; 2) drug therapy did not fully improve motor symptoms and complications; or 3) motor symptoms and complications had worsened.
Exclusion criteria were: 1) a score of ≤24 on the Mini Mental State Examination (MMSE) which tests cognition; 2) limited range of motion in the thoracic region; or 3) psychological symptoms such as severe confusion, hallucination, delusion, abnormal behavior, depression etc. or autonomic disorder.The evaluation items were used Modified Hoehn Yahr (H-Y) stage, Unified Parkinson's Disease Rating Scale (UPDRS)-Part III score.Timed Up and Go test (TUG, 3 m walking) result, and the angle of forward and lateral trunk flexion in the standing position were used to investigate their motor ability.By setting the posterior side of the sacrum as the standard plane, the angle between the plane and a line connecting the 7th cervical (C7) and 4th lumbar (L4) spinous processes was measured to obtain the angle of forward flexion.As for the angle of lateral flexion, the angle between the line connecting C7 and L4 spinous processes and a vertical line descending to the floor from the center of the line connecting the two iliac crests was measured (Figure 1).QOL in PD patients was evaluated using the Parkinson's Disease Questionnaire (PDQ)-39 scale developed by the Health Services Research Unit, University of Oxford Institute of Health Sciences, England.PDQ-39 consists of 39 questionnaire items about eight dimensions of QOL: mobility (10 items), ADL (6 items), emotional well-being (6 items), stigma (4 items), communication (3 items), bodily discomfort (3 items), social support (3 items), and cognition (4 items) (Table 1) [9] [10].The use of the PDQ-39 questionnaire items in Japanese has been validated by Kawamoto et al. [11].
Statistical analysis was performed using SPSS software (Version 22 for Windows; IBM Inc., Tokyo, Japan).The relationship between the total PDQ-39 score and each evaluation item was analyzed using the Pearson correlation coefficient, and multiple linear regression analyses were performed, with angles of forward and lateral flexions as dependent variables.Biologically plausible predictors (age, sex) were included in the original model, and eight sub-scale items of PDQ-39 dimensions were used as independent variables.In all analyses, statistical significance was set at 5% (P < 0.05).This retrospective study was approved by the Ethics Committee of the Japan Primary Care Association (approval #, 2015-002).

Results
Subjects were 38 patients (17 men, 21 women; mean age, 73.2 ± 8.6 years) with mean disease duration of 8.8 ± 5.9 years, an MMSE score of 27.3 ± 1.9, the H-Y stage of 2.8 ± 0.7, and a UPDRS-Part III score of 16.9 ± 10.2 (Table 2).Patients' clinical characteristics are shown in Table 2.A period of time measured the evaluation of PDQ-39 was 37.4 ± 10.9 minutes.

Discussion
The findings of this study showed a significant correlation between the total PDQ-39 score and the angle of lateral flexion, suggesting that abnormal posture due to lateral flexion affects QOL in these patients (Figure 2(a)).
Again, despite conventional belief, the severity of disease or mobility which includes balancing ability was not associated with the PDQ-39 score (Figure 2(c), Figure 2(d)), suggesting that these factors do not influence QOL.Previous studies of PD patients showed the involvement of motor symptoms in QOL [12] and the improvement of QOL through rehabilitation of motor symptoms [13]- [17].On the other hand, motor function determined using the Part III of UPDRS did not correlate strongly with QOL in a study conducted by Karlsen et al. of 233 PD patients and 100 healthy elderly individuals [5].Grosset et al. also reported that QOL was affected by the severity of the disease or treatment approach in only 17.3% of PD patients [18].These findings together suggest that the QOL of PD patients is affected by abnormal posture, especially lateral flexion, but not necessarily by the severity of disease or mobility.This study also investigated the association between PDQ-39 dimensions and abnormal posture due to forward or lateral flexion.A previous study of health-related QOL in patients with chronic diseases reported the importance of evaluating not only the total PDQ-39 score, but also individual QOL dimensions [19].In our study, the angles of forward and lateral flexion affected ADL, but not mobility (Table 3, Table 4).The mobility section of PDQ-39 consists of questionnaire items primarily about ambulation and outdoor activities.On the other hand, the questionnaire items in the ADL section are about movement applied in daily activities such as dining and dressing [11].The findings of this study indicate that PD patients with abnormal posture have problems with the application of movement in ADL, but not the movement itself.Therefore, it may be important for PD patients with abnormal posture to undergo the rehabilitation of movements related to ADL, in addition to the improvement of their posture and walking.
Among the QOL dimensions, the loss of social support was also a dimension involved in lateral flexion (Table 4).The social support section of PDQ-39 consists of questionnaire items on the support from family and close friends.The findings of this study indicate that PD patients with more severe lateral flexion feel strongly that they need support from others or are not provided with enough support.Cheng et al. [20] urged establishment of a team for the management of PD patients because of the various evaluation criteria and procedures.ver den Marck et al. also reported that QOL was significantly better when treatment was performed by a multidisciplinary team than by a physician alone [21].These findings suggest that support from people around the patient, such as family members and healthcare professionals, was more important for PD patients with abnormal posture to maintain and enhance long-term QOL than for those without abnormal posture.Hagell et al. [6] pointed that the sub-scale items appeared overly complex and the meaning of scale is unclear.In this study, we should interpret as useful tool regarding scale items including PDD-39 sub-scale used to evaluate QOL, although these results may have been slight suboptimal.
In this study, subjects were selected in accordance with specific selection criteria, but because this was a sin-gle institution study with a relatively small number of patients, selection bias might have resulted.In addition, because this study involved a single observation period, a long-term study, and reliability of the evaluation approach are needed to investigate the relationship between postural changes and QOL.

Conclusion
A correlation between lateral flexion and QOL in patients with PD was observed in this study.Among the PDQ-39 dimensions, ADL and communication were revealed as factors associated with abnormal posture in PD.

Figure 2 .
Figure 2. Correlation between PDQ-39 and abnormal posture, H-Y stage, or Part Ш of UPDRS.(a) Correlation of the PDQ-39 total score and the trunk lateral flexion angle; (b) Correlation of the PDQ-39 total score and the trunk flexion angle; (c) Correlation of the PDQ-39 total score and H-Y stage; (d) Correlation of the PDQ-39 total score and UPDRS Part III.

Table 2 .
Baseline characteristics of subjects with Parkinson's disease.
MMSE: Mini Mental State Examination H-Y stage: Modified Hoehn & Yahr Scale stage, TUG : Timed Up and Go test UPDRS: Unified Parkinson's Disease Rating Scale.