Nikaido et al. investigated the differences in postural control disability between idiopathic normal pressure hydrocephalus (iNPH) and Parkinson's disease (PD).
Twenty-seven iNPH patients, 20 PD patients, and 20 healthy controls (HCs) were examined using the Timed Up and Go test (TUG) and a force platform for recording the center of pressure (COP) trajectory during quiescent standing and voluntary multidirectional leaning (forward, backward, right, and left for 10 s each).
In the leaning task, postural control in PD patients was impaired during forward and backward leaning, whereas postural control in iNPH patients was impaired in all directions. In particular, postural control during right and left leaning was significantly worse in iNPH patients than in PD patients. No significant difference was observed between iNPH and PD patients in TUG and postural sway during quiescent standing.
The results showed that the characteristics of impaired voluntary COP control in iNPH and PD patients might reflect pathophysiological differences in postural instability for each disease. In particular, postural instability during right and left leaning in iNPH patients may be responsible for wider steps and a higher risk of falling 1).
Ishii et al aimed to investigate the characteristics of Parkinsonian features assessed by the unified Parkinson's disease rating scale (UPDRS) and determine their correlations with the computed tomography (CT) findings in patients with idiopathic normal pressure hydrocephalus (iNPH). The total score and the scores for arising from chair, gait, postural stability, and body hypokinesia in the motor examination section of UPDRS were significantly improved after shunt operations. Stepwise multiple regression analysis revealed that postural stability was the determinant of the gait domain score of the iNPH grading scale. The canonical correlation analysis between the CT findings and the shunt-responsive Parkinsonian features indicated that Evans index rather than midbrain diameters had a large influence on the postural stability. Thus, the pathophysiology of postural instability as a cardinal feature of gait disturbance may be associated with impaired frontal projections close to the frontal horns of the lateral ventricles in the iNPH patients 2).