Intermittent gait disturbance in idiopathic normal pressure hydrocephalus
Gait disturbances in idiopathic normal pressure hydrocephalus (iNPH) have been historically characterized by a persistent broad‐based, short‐stepped “magnetic” gait.1 However, the precise temporal nature of long‐distance gait has not been accurately described. We have recently identified an intermittent type of gait disturbance (IGD) in iNPH patients using the 6‐minute walk test (6MWT).5 This pattern was particularly seen in mild and early stages of iNPH and seemed to be related to falls. Typically, patients complain about falling, but do not mention deterioration of gait after a walking load. Furthermore, IGD is difficult to identify in the examination room, because it is not apparent in short‐distance walking. Gait disorders in iNPH are usually considered to be a persistent, not transient deficit. Perhaps for this reason, evaluation of gait function included only used short‐distance gait testing, such as the TUG,2 the 10‐ to 25‐meter walk test,7 or other gait scoring systems that employ short‐distance gait measures.10
The 6MWT is widely used as gait loading test; reliability and validity of the 6MWT have been established as a tool to evaluate walking endurance for the heart and lung diseases.5 However, 6MWT has not been applied to evaluate gait performance of iNPH patients. The purposes of this study were to clarify the temporal gait profile of IGD during long‐distance gait and to confirm the difference in treatment effect after cerebrospinal fluid (CSF) shunting in patients with and without IGD. A discussion of the pathophysiological mechanisms of IGD in iNPH and the implications of IGD as an early diagnostic marker of iNPH are presented.