Abstract Details

NPH is a condition of disturbed CSF dynamics, defined by a clinical triad of gait disturbance, urinary complaints, and cognitive decline, in the presence of hydrocephalus. Current treatment is implantation of a VPS, which is indicated followed an improvement on a CSF tap test (removal of 30-50 ml of CSF while measuring change in "Timed Up and Go (TUG)"). This in an invasive test with several drawbacks. There is an ongoing need for a safer, objective procedure to allow clinicians more precise prediction of treatment response.

Assess the utility of Delphi as an alternative for CSF tap test in prediction of response to ventriculoperitoneal shunt (VPS) in normal pressure hydrocephalus (NPH).

Twenty "probable NPH" patients and 20 age matched healthy controls underwent a neurological exam, cognitive evaluation and brain MRI scans.  

All subjects performed Delphi, a non-invasive measure that probes brain network response, through induction of focused magnetic stimulation over selected brain networks, while simultaneously measuring the brain electrophysiological response. A subset of subjects which underwent VPS were evaluated for their symptoms 1-3 months following the operation.

Significant differences were measured in Delphi Waveform Adherence (WFA) between NPH patients from age matched HC (p<0.01) in response to primary motor cortex stimulation and lower motor threshold (p<0.01). Delphi WFA and the Interhemispheric Coherence (IHC) of Delphi waveform in response to M1 stimulation at baseline, was highly correlated to the change in symptoms post VPS (r=-0.84, p=0.02 and r=-0.92 p=0.0007 respectively) as opposed to CSF Tap test (r=-0.58, p=0.18) which did not show significant correlation.

These results demonstrate Delphi’s potential superiority in the prediction of VPS effect in NPH. If verified in a larger sample this might pose Delphi as a substitute diagnostic test for NPH and an enhanced predictive tool for the response to VPS thus enabling better patient management.