Idiopathic normal pressure hydrocephalus and frontotemporal dementia: an unexpected association

Abstract

Idiopathic normal pressure hydrocephalus has a complex multifactorial pathogenesis and is associated with Alzheimer’s disease in many patients. To date, it is not well known if a similar association exists with behavioural variant of frontotemporal lobar degeneration. In a first step, we compare the prevalence of idiopathic normal pressure hydrocephalus in two groups of patients, one with behavioural variant of frontotemporal lobar degeneration (n = 69) and the other with Alzheimer’s disease (n = 178). In a second step, we describe more precisely the phenotype of patients with the association of idiopathic normal pressure hydrocephalus and behavioural variant of frontotemporal lobar degeneration. Firstly, we report that the prevalence of idiopathic normal pressure hydrocephalus was far higher in the group of patients with behavioural variant of frontotemporal lobar degeneration than in the group of patients with Alzheimer’s disease (7.25% and 1.1%, respectively, P = 0.02). Secondly, we show that patients with the double diagnosis share common clinical and para-clinical features of both idiopathic normal pressure hydrocephalus and behavioural variant of frontotemporal lobar degeneration patients, including CSF shunting efficacy in real life experience. Overall, our results suggest a link between these two conditions and should encourage neurologists to look for idiopathic normal pressure hydrocephalus in their behavioural variant of frontotemporal lobar degeneration patients in the event of gait disturbances; the benefit/risk balance could indeed be in favour of shunt surgery for selected patients with this newly described entity.

Increased prevalence of normal pressure hydrocephalus in both variants of frontotemporal dementia: a 10-year retrospective study

“…In conclusion, our 10-year study reinforces the findings of Pouclet-Courtemanche and colleagues 1 regarding the increased prevalence of iNPH among patients with FTD. Here, we further demonstrate that this increased prevalence concerns both bvFTD and PPA variants with a 2-fold higher prevalence of iNPH in the bvFTD compared with the PPA variants.…”

“…We read with great interest the article by Pouclet-Courtemanche and colleagues 1 published recently in Brain Communications . The article reported an increased prevalence of idiopathic normal pressure hydrocephalus (iNPH) among patients with a behavioural variant frontotemporal dementia (bvFTD) (7.25%) in comparison with those with Alzheimer’s disease (1.1%).…”

“…The article reported an increased prevalence of idiopathic normal pressure hydrocephalus (iNPH) among patients with a behavioural variant frontotemporal dementia (bvFTD) (7.25%) in comparison with those with Alzheimer’s disease (1.1%). 1 Therefore, we proposed to evaluate this high prevalence of iNPH in patients with FTD (not only focusing on bvFTD) followed at the Leenaards Memory Center of the Lausanne University Hospital between January 2013 and December 2022.…”

Response to: increased prevalence of normal pressure hydrocephalus in both variants of frontotemporal dementia: a 10-year retrospective study

“…We are very grateful to Dr. Pizzarotti and Prof. Allali 1 for their interest in our article entitled: ‘Idiopathic normal pressure hydrocephalus and frontotemporal dementia: an unexpected association’ 2 and for this first replication of our study in a new cohort of frontotemporal lobar degeneration (FTLD) patients.…”