Distinctive features of bimanual coordination in idiopathic normal pressure hydrocephalus.

Background: Idiopathic normal pressure hydrocephalus (iNPH) is characterized by cerebrospinal fluid circulation disorders, and presents as gait and balance disturbances similar to those observed in other incurable neurological diseases. Although previous studies have reported deficits in bimanual coordination among patients with iNPH, these potential pathological characteristics have not received much attention to date. This study investigated the temporal characteristics of a bimanual finger-tapping task in patients with iNPH, focusing on within- and between-hand coordination.

Methods: Study participants comprised three groups: patients with iNPH (N = 19, mean age = 76.9 ± 5.6 years), older adults (N = 19, 76.4 ± 5.3 years), and younger adults (N = 13, 32.2 ± 8.5 years). Participants performed a bimanual finger-tapping task under five conditions that manipulated the temporal differences between the two taps.

Results: The iNPH group exhibited significantly greater errors in both within- and between-hand coordination tasks compared to the other two groups.

Conclusion: These results suggest that assessing temporal errors in bimanual coordination tasks, particularly within-hand coordination, may be useful for uncovering pathological characteristics specific to iNPH.