Impact of Early Intervention for Idiopathic Normal Pressure Hydrocephalus on Long-Term Prognosis in Prodromal Phase

Yoshinaga Kajimoto; Masahiro Kameda; Akihiro Kambara; Kenji Kuroda; Shohei Tsuji; Yasutaka Nikaido; Ryuichi Saura; Masahiko Wanibuchi

doi:10.3389/fneur.2022.866352

Impact of Early Intervention for Idiopathic Normal Pressure Hydrocephalus on Long-Term Prognosis in Prodromal Phase

Front Neurol. 2022 Apr 11:13:866352. doi: 10.3389/fneur.2022.866352. eCollection 2022.

Authors

Yoshinaga Kajimoto¹, Masahiro Kameda¹, Akihiro Kambara¹, Kenji Kuroda², Shohei Tsuji², Yasutaka Nikaido², Ryuichi Saura³, Masahiko Wanibuchi¹

Affiliations

¹ Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
² Clinical Department of Rehabilitation, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
³ Department of Physical and Rehabilitation Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.

Abstract

Objectives: Because the progression of idiopathic normal pressure hydrocephalus (iNPH) is partially irreversible, we hypothesized that early intervention would markedly improve its prognosis. To test this hypothesis, we retrospectively investigated the long-term prognosis of patients with early intervention in the prodromal phase of iNPH.

Methods: We defined the prodromal phase of iNPH as a 3m Timed Up and Go (TUG) of 13.5 s or less and a Mini-Mental State Examination (MMSE) of 24 or more. Of the 83 iNPH patients who underwent shunt surgery at Osaka Medical and Pharmaceutical University Hospital over 3 years from January 2015, 12 prodromal phase cases (73.3 ± 6.2 years, 10 males and 2 females) were included in the study. The iNPH grading scale (INPHGS), MMSE, Frontal Assessment Battery (FAB), intermittent gait disturbance (IGD), social participation status, and development of comorbidities were evaluated over 4 years.

Results: Preoperative MMSE was 27.2 ± 1.5, FAB was 14.1 ± 1.8, TUG was 10.7 ± 1.4 s, and total iNPHGS was 2.8 ± 1.4. At 1, 2, 3, and 4 years postoperatively, total INPHGS improved to 0.8, 0.9, 1.5, and 1.7, respectively, and remained significantly better than preoperatively except at 4 years postoperatively. The MMSE improved slightly to 27.5 after 1 year and then declined by 0.35 per year. After 4 years, the mean MMSE was 26.1, and only one patient had an MMSE below 23. FAB improved to 15.2 after 1 year and then declined slowly at 0.85/year. Ten patients (83%) maintained a high capacity for social participation postoperatively. The preoperative tendency to fall and IGD in 9 (75%) and 8 (67%) patients, respectively, completely disappeared postoperatively, resulting in improved mobility. Shunt malfunction associated with four weight fluctuations and one catheter rupture caused temporary worsening of symptoms, which were recovered by valve re-setting and catheter revision, respectively.

Conclusion: Early intervention in the prodromal phase of iNPH patients maintained good cognitive and mobility function and social participation ability in the long term. The maintenance of long-term cognitive function suggests its preventive effect on dementia. To realize early intervention for iNPH, it is desirable to establish an early diagnosis system for iNPH.

Keywords: CSF shunt; early intervention; hydrocephalus surgery; idiopathic normal pressure hydrocephalus (iNPH); long-term outcome; prodromal phase.