Long-Term Prognosis of Cognitive Function in Patients With Idiopathic Normal Pressure Hydrocephalus After Shunt Surgery.

Akihiro Kambara,Ryuichi Saura,Ryokichi Yagi,Kenji Kuroda,Toshihiko Kuroiwa,Shinji Kawabata,Naokado Ikeda,Motomasa Furuse,Yoshinaga Kajimoto,Shohei Tsuji,Naosuke Nonoguchi,Masahiko Wanibuchi

doi:10.3389/fnagi.2020.617150

Abstract

The long-term prognosis of cognitive function in patients with idiopathic normal pressure hydrocephalus (iNPH) remains unclear. This study aimed to determine the long-term prognosis of cognitive function in patients with iNPH, as well as the factors related to it. It included 48 patients with iNPH who were treated with cerebrospinal fluid shunting between January 2015 and December 2017 at Osaka Medical College Hospital, with follow-up evaluation of their cognitive function for >2 years. Cognitive function was measured using the Mini-Mental State Examination (MMSE) preoperatively and at 3 months, 1 and 2 years post-operatively. The mean MMSE score (22.4 ± 5.4 preoperatively) improved at 3 months [23.8 ± 5.0 (p = 0.0002)] and 1 year [23.7 ± 4.8 (p = 0.004)] post-operatively. At 2 years post-operatively, they were able to maintain their preoperative level (22.6 ± 5.3). The patients were classified in to the cognitive decline group [11 (23%) patients; a decrease in the MMSE score by ≥ 2 points 2 years after surgery] and the maintenance/improvement group [37 (77%) patients]. Univariate and receiver operating characteristic analyses were performed for the two groups to identify factors associated with cognitive prognosis. In both groups, the patients who were younger (p = 0.009) or had milder symptoms (p = 0.035) had a better long-term prognosis of cognitive function. The cutoffs for age and disease severity (idiopathic normal-pressure hydrocephalus grading scale; INPHGS) were 78 years (area under the curve = 0.77) and 5 points (area under the curve = 0.71), respectively. In conclusion, most patients (77%) were able to improve and maintain cognitive function for at least 2 years after surgery. The fact that disease severity and age are associated with cognitive prognosis suggests that early iNPH intervention is desirable to improve cognitive prognosis.

Highlights

Idiopathic normal pressure hydrocephalus is clinically characterized by gait disturbance, dementia, and urinary incontinence (Vanneste, 2000; Relkin et al, 2005)
Given that the progression of gait and cognitive impairment leads to the requirement of care at home and in the community, Idiopathic normal pressure hydrocephalus (iNPH) is becoming increasingly important with respect to public health and social security
Out of the 72 patients with iNPH who were treated with Cerebrospinal fluid (CSF) shunting from January 2015 to December 2017 at Osaka Medical College Hospital, we included 48 patients whose cognitive function could be evaluated with follow-up for > 2 years

Summary

Introduction

Idiopathic normal pressure hydrocephalus (iNPH) is clinically characterized by gait disturbance, dementia, and urinary incontinence (Vanneste, 2000; Relkin et al, 2005). Cerebrospinal fluid (CSF) shunting can be used to treat it (Kuriyama et al, 2017). Given that the progression of gait and cognitive impairment leads to the requirement of care at home and in the community, iNPH is becoming increasingly important with respect to public health and social security. To reduce the caregiving burden on families and society, iNPH treatment for short- and long-term improvement and maintenance of gait and cognitive function is required. There have been numerous reports regarding the long-term prognosis of gait function after CSF shunt surgery in patients with iNPH. Gait function was found to be improved in ∼80% of cases at 3 years post-operatively; the long-term prognosis of gait function was good (McGirt et al, 2008; Pujari et al, 2008)

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