Change in Cognition and Frailty After Shunt Surgery in Idiopathic Normal Pressure Hydrocephalus (iNPH)

September 2, 2026 updated by: Magnhild Skråmestø Dejgaard, Oslo University Hospital
The goal of this observational study is to describe changes in cognitive profile and frailty from pre shunt to one year after the shunt surgery and to identify clinical predictors of an improvement in terms of cognition and frailty during the same period. The main objective is to identify predictors of the effect on the planned shunt surgery on cognition and frailty.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Frailty is a consequence of cumulative decline in many physiological systems during a lifetime and implies an increased vulnerability to poor resolution of homoeostasis after a stressor event. Frailty is emerging as an important risk factor for mortality and postoperative complications but has to a limited degree been studied in iNPH.

The investigators have previously, in a cross-sectional design, described cognitive profile and frailty status in patients with iNPH accepted for shunt surgery at Oslo University Hospital. The aims of this longitudinal follow-up of the same patient cohort are twofold:

  1. to describe changes in cognitive profile and frailty from pre shunt to one year after the shunt surgery, and
  2. to identify clinical predictors of an improvement in terms of cognition and frailty during the same period.

The patient sample consists of 276 patients that were accepted for shunt surgery at Oslo University Hospital in the period from September 2018 to December 2023. Their mean age was 73.1 years (range 52-85), 61% were men, and their mean length of education was 12.5 years.

For frailty, the investigators used a 35 items Frailty Index (FI). Most of the items (frailty indicators) are scored 0 (not present) or 1 (present), while some of them have a graded score. The index is the sum score divided by the number of items, varying from 0.0 (no frailty) to 1.0 (extreme frailty). The investigators used the same approach for assessment of the degree of frailty within each frailty domain. Cognitive decline is considered as one component of frailty. Accordingly, the Mini Mental State Examination (MMSE) is part of the FI and has a graded score. MMSE sum score <21 gives a score of 1 at this particular FI item, an MMSE score of 21-23 gives an item score of 0.7, an MMSE score of 24-26 gives an item score of 0.3, whereas an MMSE score of 27-30 does not contribute to the FI. MMSE is a screening test covering several cognitive domains. The investigators will use MMSE to evaluate the cognitive dimension of frailty as described here, whereas more specific cognitive tests are utilised to assess failure in particular cognitive domains.

Preoperatively, the mean FI score was 0.23, and the most common frailty markers were in the domains of physical function and instrumental activities of daily living (iADL). On the group level, the iNPH patients were impaired on all cognitive domains preoperatively, but compared to patients with Alzheimer's disease, they had relatively better-preserved memory and more severe impairments in phonemic fluency.

224 (83%) patients were assessed one year postoperatively. The same cognitive tests and frailty assessments were carried out, making it possible to calculate simple change scores as score(postop) - score(preop). The investigators will compare baseline characteristics of patients lost to follow-up descriptively with those followed, to assess potential attrition bias.

A detailed Statistical Analysis Plan (SAP) describes the planned analytical approach.

Study Type

Observational

Enrollment (Actual)

276

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Norway
      • Oslo, Norway
        • Department of Geriatric Medicine, Oslo University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

see inclusion criteria

Description

Inclusion Criteria:

• Diagnosed with iNPH and accepted for shunt surgery according to the American-European guidelines at Department of Neurosurgery, Oslo University Hospital, Rikshospitalet.

Exclusion Criteria:

  • Non-native speakers of Norwegian
  • Patients who had completed ≤ 3 cognitive tests

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Patients with idiopathic normal pressure hydrocephalus accepted for shunt surgery
Procedure: Ventriculoperitoneal shunt
Patients are already accepted for shunt surgery. The investigators will describe changes in cognitve profile and frailty from pre shunt to one year after to identify clinical predictors for shunt response.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Trail Making Test A (TMT A) from preoperative to postoperative in patients with idiopathic normal pressure hydrocephalus (iNPH).
Time Frame: 12 month
TMT A is a cognitive test assessing attention and psychomotor speed and is scored in seconds. The investigators have defined a Minimum Clinically Important Difference (MCID) as an improvement of 20 seconds.
12 month
Change in Frailty Index (FI) from preoperative to postoperative in patients with idiopathic normal pressure hydrocephalus (iNPH).
Time Frame: 12 months
For frailty, a 35 items FI was used. Most of the items (frailty indicators) are scored 0 (not present) or 1 (present), while some of them have a graded score. The index is the sum score divided by the numbers of items, varying from 0.0 (no frailty) to 1.0 (extreme frailty). The investigators have defined a Minimum Clinically Important Difference (MCID) as a decrease in the FI of 0.05 (5 %) or more.
12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Other measures of cognition and frailty
Time Frame: 12 months
Mini Mental State Examination (MMSE-NR3) is a cognitive screening test from 0 - 30 covering several cognitive domains. Higher score indicates better function. MMSE is part of the FI and has a graded score. MMSE sum score <21 gives a score of 1 at this particular FI item, an MMSE score of 21-23 gives an item score of 0.7, an MMSE score of 24-26 gives an item score of 0.3, whereas an MMSE score of 27-30 does not contribute to the FI. MCID: 2 points.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
Personal activities in daily living (pADL) are subscales of the FI and are scored from 0-7, higher score indicates more need for help in daily living. An improvement is set to at least 5 % for subscale as a limit for MCID.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
Instrumental activities in daily living (iADL) are subscales of the FI and are scored from 0-7, higher score indicates more need for help in daily living. An improvement is set to at least 5 % for subscale as a limit for MCID.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
Gait speed (m/s) is measured from 10 m walk and 0.1 m/s or more is accepted as clinically meaningful. MCID is set to 0.1 m/s.
12 months
Other measures of cognition and frailty
Time Frame: 12 months

Cognitive variables:

For assessing memory, delayed word recall is assessed using a normalized score ranging from 0 to 1. This score is derived from either the Ten-Word Test from Consortium to Establish a Registry for Alzheimer's disease (CERAD) or the Rey Auditory Learning Test. These scores are min/max normalized in order to achieve one common measure of delayed word recall: Normalized score = (raw score - lowest possible score)/(higest possible score - lowest possible score). The investigators have defined MCID of 0.2 words.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
Figure Construction Test from CERAD is a cognitive test assessing visuoconstructive abilities and its scored from 0 to 11. Higher score reflects better performance. MCID: 2 points.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
Trail Making Test B is a cognitive test assessing attention, psychomotor speed and executive function and is scored in seconds. MCID: 60 seconds.
12 months
Other measures of cognition and frailty
Time Frame: 12 months
The Phonemic Fluency Test is a cognitive test assessing language abilities and executive function. Higher score reflects better performance. MCID:10 words.
12 months

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Responder analysis
Time Frame: 12 months

Based on the MCID limits for each outcome, the investigators will define a responder for each outcome as a patient improving that much or more from the preoperative to the one-year postoperative assessment and will calculate the percentage of responders for each of the outcomes.

The investigators will then analyse predictors for shunt response on each of the ten outcome variables.

Candidate variables in the prediction models are:

1. Age. 2. Sex. 3. Education. 4. MMSE-NR3 score. 5. Gait speed. 6. FI score. 7. Difference in z-score between phonemic fluency and delayed recall at baseline. 8. Cluster affiliation (based on a previously published cluster analysis. The analytic strategy is described in detail in the Statistical Analysis Plan (SAP) that is uploaded as a separate document.
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Oslo University Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2018

Primary Completion (Actual)

June 19, 2025

Study Completion (Actual)

June 19, 2025

Study Registration Dates

First Submitted

May 27, 2026

First Submitted That Met QC Criteria

June 5, 2026

First Posted (Actual)

June 11, 2026

Study Record Updates

Last Update Posted (Actual)

September 8, 2026

Last Update Submitted That Met QC Criteria

September 2, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 10150 (formerly 2019/547)
  • Funded by (Other Identifier: Department of Geriatric Medicine Oslo University Hospital)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The raw data supporting the conclsion of the article will be made available, following ethic committee guidelines on resonable request from any qualified investigators.

IPD Sharing Access Criteria

Data sets are available from the PI on request.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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