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

Abstract

Lateral trunk flexion (LTF) is one of the postural abnormalities that can develop in patients with Parkinson's disease (PD). It is an important clinical sign, and it affects activities of daily living and quality of life. 1 Although the pathophysiology of LTF in PD has not been fully clarified, we know that alterations in sensory-motor integration pathways result in abnormal body schema perception and cognition, and this is one of the reasons why patients are unable to appropriately perceive their own physical posture. 2 Healthy individuals are able to perceive their own verticality accurately; the perception of body verticality, also known as the subjective postural vertical in the coronal plane (SPVc), allows these individuals to recognize deviations of 0.1° from the vertical position, despite their eyes being closed. 3 To the contrary, most patients with PD do not notice LTF in themselves when it develops. 4 Lateral trunk flexion (LTF) >10° is defined as Pisa

Subjective Postural Vertical as a Prognosticator of Lateral Trunk Flexion in Patients With Parkinson's Disease.

“…The SPV ratio is used to evaluate the SPV with reference to the axis of lateral exion, so an SPV ratio of ≥ 1 means that the SPV angle is larger than the LTF angle. In a previously reported longitudinal study, cases in which the SPV angle was larger than the LTF angle were also observed, suggesting use of the SPV ratio as a predictor of the course of LTF (11). Our study, reported herein, veri ed a relation between the SPV ratio and change in the LTF angle at 1 year, con rming potential usefulness of the SPV ratio obtained on initial evaluation as a prognosticator of the course of PD-associated LTF.…”

“…The mean value of these measurements was used as the SPV angle. The SPV ratio was the SPV measured with reference to the axis of lateral exion, and in accordance with preceding studies, was calculated by dividing the SPV angle by the LTF angle (SPV ratio = SPV angle/LTF angle) (11).…”

“…The standard axis was a vertical line crossing L5 and descending to the oor. The axis of forward exion was de ned as the line connecting C7 and L5 observed along the sagittal plane, while the axis of lateral exion was de ned as a line connecting C7 and L5 observed along the coronal plane (11,12). SPV evaluation.…”

“…In addition, as the severity of LTF increases, patients' underestimation of the degree of deviation increases (10). In a previous study of LTF in patients with PD (11), we examined the subjective postural vertical (SPV) angle, de ned as the subjective perception of a vertical position with reference to the vertical axis. We also examined the SPV ratio, de ned as the SPV angle with reference to the axis of lateral exion, and we showed that the SPV ratio affects LTF.…”

Sex differences in posture and vertical perception of gait function in patients with Parkinson's disease

“…Thus, to date, sex differences in the effect of posture on gait function in PD patients have yet to be clari ed. Furthermore, it has been hypothesized that subjective vertical position (SPV) [20], which affects forward trunk exion (FTF) and LTF in PD patients, also affects gait [21,22]; however, the in uence of SPV on gait according to sex has not been investigated. This study examined the in uence of posture and vertical perception on gait function in PD patients by sex; to our knowledge, this is the rst such evaluation.…”