Motor Network Neurophysiological (TMS-EEG) Markers as Predictors of Long-term Outcomes Following Ventriculoperitoneal Shunt in Normal Pressure Hydrocephalus
Tal Davidy1, Alexandra Suminski1, Yakov Zauberman1, Tsvia Fay-Karmon1, Saar Anis2, Adi Saar1, Noa Zifman3, Hilla Fogel3, Orit Lesman-Segev1, Sharon Hassin-Baer4
1Sheba Medical Center, 2Cleveland Clinic, 3QuantalX Neuroscience Ltd., 4Chaim Sheba Medical Center
Objective:
This study evaluated whether a TMS-evoked potential (TEP)-based test, Delphi-MD, can predict long-term (over one year) response to VPS as an ancillary tool to improve decision-making.
Background:

Current approaches for normal pressure hydrocephalus (NPH) depend on clinical assessment, imaging, and procedures like CSF tap tests to guide ventriculoperitoneal shunt (VPS) decisions. 

Design/Methods:

Forty-one patients with possible iNPH underwent Delphi-MD evaluation of wave form adherence (WFA), a composite measure assessing how closely their TEPs resembled an ideal benchmark TEP. Eighteen patients received VPS based on multidisciplinary team decision. Response was assessed over >1 year using the clinical global impression of change (CGIC), along with the 10-meter timed up and go test and the modified Rankin scale.

Results:

Responders showed higher baseline left primary motor cortex (M1L) WFA values than non-responders (median 0.51 [95% CI 0.36–0.76] vs. 0.14 [95% CI -0.02–0.38], p=0.012). Furthermore, M1L WFA effectively distinguished responders (11/18) from non-responders (7/18), with an ROC-AUC of 0.935 (bootstrap 95% CI 0.792–1.00, p<0.0001). The cutoff, validated via leave-one-out cross-validation, yielded 90.9% sensitivity, 85.7% specificity, and 88.9% accuracy. CSF tap tests, in contrast, did not predict responsiveness.

Conclusions:

This study indicates that higher M1L WFA obtained through Delphi-MD, signifies better preservation and functional integrity of the motor network in patients with probable iNPH that had a sustained response to VPS than those that did not. Thus Delphi-MD shows promise as an objective, accurate, and accessible ancillary screening tool for iNPH candidates, prior to referral for VPS treatment.

10.1212/WNL.0000000000217239
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.