A combined cognitive and gait quantification to identify normal pressure hydrocephalus from its mimics: The Geneva's protocol

Abstract

Objectives: Idiopathic normal pressure hydrocephalus (iNPH) is very prevalent in aging, underdiagnosed, and represents a rare cause of reversible neurological condition. The clinical triad of iNPH - gait, cognitive and urinary symptoms - and its neuroradiological features (i.e. ventriculomegaly) are not specific and found a various neurodegenerative and/or vascular conditions. We present our iNPH standardized protocol at the Geneva University Hospitals involving a multispecialty team of behavioral neurologists, neurosurgeons, neuropsychologists, engineers, and physical therapists. Based on a pragmatic approach, the goal of this protocol is to improve the identification of older patients with iNPH from its mimics (i.e. vascular dementia or other parkinsonian syndromes).

Patients and methods: We used a novel standardized paradigm with a simultaneous quantification of cognition and gait (dual task gait assessment and mental imagery of locomotion) before and 24h after CSF tapping.

Results: We assessed 125 patients with suspicion of iNPH (age: 75.9±7.4years; 34.4% female) in 5 years: 54.4% of probable/possible iNPH and 45.6% of mimics. Among the mimics, vascular dementia (24.6%) and patients with multifactorial conditions (19.9%) were the two most common diagnoses. A total of 27 patients with iNPH (39.7%) accepted the neurosurgical shunt procedure.

Conclusion: This report shows that a quantified gait and cognitive assessment - using dual-task paradigms - before and after CSF tapping is feasible among older adults with suspicion of iNPH and that this multidisciplinary approach contributes to the identification of patients with iNPH from its mimics.

Keywords: Assessment; Dual task; Gait analysis; Mental imagery; Mimics; Neuropsychology; Normal pressure hydrocephalus.