Postural performance and plantar cutaneous vibration perception in patients with idiopathic normal pressure hydrocephalus

Abstract

Objective: To investigate whether impaired plantar cutaneous vibration perception contributes to postural disturbance in idiopathic normal pressure hydrocephalus (iNPH).

Methods: Three different groups were tested: iNPH-patients (iNPH), iNPH-patients after surgical shunt therapy (iNPH shunt), and healthy subjects (HS). Postural performance was quantified during quiescent stance on a pressure distribution platform. Vibration perception threshold (VPT) was measured using a modified vibration exciter to apply stimuli to the plantar foot.

Results: Regarding postural performance, iNPH showed significantly higher values for all investigated center of pressure (COP)-parameters compared to HS, which suggests impaired postural control. Shunted patients presented a tendency towards better postural control in contrast to non-shunted patients. VPTs did not differ significantly between all investigated groups, which suggests comparable plantar cutaneous vibration perception.

Conclusion: Patients with iNPH suffer from poor postural stability, whereas shunting tends to affect postural performance positively. Plantar cutaneous vibration perception seems to be comparable between all investigated study groups. Consequently, postural disturbance in iNPH cannot clearly be ascribed to defective plantar cutaneous input.

Keywords: Idiopathic normal pressure hydrocephalus; Plantar cutaneous vibration perception; Postural performance; Shunt.

Figure 1

Plantar vibration examination at the first metatarsophalangeal joint.

Figure 2

Group comparisons including statistically significant p-values for COP-parameters: A) 95% confidence area (ellipse-shaped area, comprising 95 % of COP-data); B) range AP (range of captured COP-data along AP direction); C) range ML (range of captured COP-data along ML direction); D) v mean (mean velocity calculated over each frame); E) v mean AP (mean velocity calculated over each frame in AP direction); F) v mean ML (mean velocity calculated over each frame in ML direction); the level of significance was Bonferroni adjusted to α = 0.0167.

Figure 3

VPT amplitude group comparison for both anatomical locations: A) heel, B) met I; the level of significance was Bonferroni adjusted to α = 0.0083. No significant differences could be found.