Forward flexion of trunk in Parkinson's disease patients is affected by subjective vertical position

Abstract

PurposeNo method has been established to evaluate the dissociation between subjective and objective vertical positions with respect to the self-awareness of postural deformity in patients with Parkinson’s disease (PD). The purpose of this study was to demonstrate, from the relationship between an assessment of the dissociation of subjective and objective vertical positions of PD patients and an assessment based on established PD clinical evaluation scales, that the dissociation regarding vertical position is a factor in the severity of the forward flexion of trunk (FFT).MethodsSubjects were 39 PD patients and 15 age-matched healthy individuals (control group). Posture was evaluated with measurement of FFT angle during static standing and the subjective vertical position (SV) of the patient. For evaluation of motor function, the Modified Hoehn & Yahr scale, Unified Parkinson’s Disease Rating Scale (UPDRS), 3-m Timed Up and Go Test (TUG), and Functional Reach Test (FRT) were used.ResultsIn PD patients, FFT angle in the 3rd tertile of patients was 13.8±9.7°, significantly greater than those in the control group and the 1st and 2nd tertiles of PD patients (control group vs 3rd tertile, p = 0.008; 1st tertile vs 3rd tertile, p<0.001; 2nd vs 3rd tertile, p = 0.008). In multiple regression analysis for factors in the FFT angle, significant factors were SV, disease duration, and the standard deviation of each SV angle measurement.ConclusionThe dissociation between SV and objective vertical position affects the FFT of PD patients, suggesting an involvement of non-basal ganglia pathologies.

Subjective Vertical Position Allows Prediction of Postural Deterioration in Patients with Parkinson’s Disease

“…On the basis of the hypothesis that a forward-directed increase in the SV is an exacerbating factor for FFT in patients with PD, changes in clinical markers, including the SV angle and FFT angle, were investigated after 1 year. Positive correlation was observed between the SV angle and the FFT angle, both at baseline and 1 year later, indicating a relationship between SV and FFT, as previously reported [20]. No significant change was found in the FTT angle after 1 year, and no significant correlation was found between the baseline and 1-year FFT angles, indicating that the baseline FFT angle is not a contributing factor to the change in FFT angle at 1 year.…”

“…This difficulty stems from the lack of a clear definition of the disease state [14] due to its multifactorial etiology, with contributing factors that include rigidity [15], dystonia [16], drug inducement [17], and proprioceptive integration [18] and vestibular sensation deficits [19]. On investigating the relationship between FFT and PD patients' subjective vertical position (SV) [20], we found larger SV angles among patients with larger FFT angles. Conversely, large SV angles were also observed in some PD patients with mild or moderate FFT, indicating that the SV angle is not determined by severity of the FFT.…”

Subjective postural vertical in Parkinson's disease with lateral trunk flexion

“…Patients were asked to stand in a natural position with their eyes open, and we evaluated the LTF, forward trunk flexion (FTF), and lateral neck flexion (LNF) angles. Posture was evaluated as described in previously reported studies 9‐11 . Reflective markers were attached to the skin above the spinous processes of the seventh cervical (C7) and fifth lumbar (L5) vertebrae (Figure 1A).…”

“… 1 The FTF angle was evaluated along the sagittal plane by measuring the angle between the vertical axis and axis of anterior flexion (Figure 1C). 9,10 The LNF angle was evaluated along the coronal plane by measuring the angle between the standard axis and axis of cervical lateral flexion (Figure 1D). When the direction of LNF was opposite that of the LTF, the LNF angle was recorded as a negative value.…”

Deterioration of postural deformity in Parkinson’s disease patients with punding and hobbyism

“…The FFT and LFT angles, which were postural measurement variables in this study, were determined as the angle between a vertical line running through the 4th lumbar vertebra (L4) to the floor and the actual trunk line, which connected the 7th cervical vertebra (C7) and L4 (Fig. 1b, c) [16]. A clinical assessment was performed using the H-Y scale and parts I to IV of the Unified Parkinson's Disease Rating Scale (UPDRS).…”