Category: Parkinsonism (Other)
Objective: Assess the ability of neurophysiological measure of TMS evoked potentials to predicts response to shunting in NPH.
Background: NPH is an age-related condition of disturbed CSF dynamics, defined by a clinical triad of gait disturbance, urinary dysfunction, and cognitive decline, in the presence of hydrocephalus. While symptoms may improve with ventriculoperitoneal shunt (VPS), patient selection is based on an invasive procedure of drainage of a large volume of CSF (CSF tap-test, CTT) showing improvement of gait speed, a test that suffers from low sensitivity.
Method: Patients with possible idiopathic NPH underwent a Delphi TMS-EEG (transcranial magnetic stimulation) evaluation, before performing a CTT. Delphi is an accessible automated measurement of multifocal TMS-evoked potentials (TEPs). Patients were re-evaluated one year following VPS, using the clinical global impression of change scale (CGI-C) by a movement disorder specialist.
Results: Fourty-one possible iNPH were enrolled, of which 18 patients [age 75.4 (±4.3) years, n females, and MoCA: 19.4 ±4.1] underwent VPS implantation according to multidisciplinary team considerations, blinded to Delphi results. Eleven patients (61%) improved following VPS when assessed 1 year or longer from VPS (CGI-C<4).
Delphi TEP from right dorsolateral prefrontal cortex (DLPFC) and the left primary motor cortex (M1) waveform adherence (a composite numeric quantitative measure that reflects the normality of the TEP response) discriminated NPH responders from non-responders: ROC-AUC=0.9 [95% CI: 0.76-1.0], P=0.006 with a sensitivity of 83.3% and specificity of 90.9% (Figure 1) and ROC-AUC=0.93 [95% CI: 0.82-1.0], p=0.002, sensitivity of 85.7% and, specificity of 90.9% (Figure 2), respectively, were both superior to prediction by CTT.
Conclusion: Probing the prefrontal and motor networks physiology with Delphi (TMS-EEG) and quantifying TEP WFA, provides a direct measurement of brain function and may be an alternative screening method for response to shunting in iNPH , which is safer, objective and more accurate than CTT.
To cite this abstract in AMA style:
T. Davidi, S. Anis, Y. Zauberman, T. Fay-Karmon, A. Saar, N. Zifman, H. Fogel, O. Lesman-Segev, S. Hassin-Baer. Frontal and Motor TMS Evoked Potentials Predict Response to Ventriculoperitoneal Shunt in NPH [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/frontal-and-motor-tms-evoked-potentials-predict-response-to-ventriculoperitoneal-shunt-in-nph/. Accessed October 5, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/frontal-and-motor-tms-evoked-potentials-predict-response-to-ventriculoperitoneal-shunt-in-nph/