Upper extremity motor function before and after the cerebrospinal fluid tap test in patients with idiopathic normal pressure hydrocephalus:A retrospective study

To the Editor:Idiopathic normal pressure hydrocephalus(iNPH)patients present disturbances in gait,cognition,and/or control of urination with neuroimaging characterized by enlargement of the cerebral ventricles.Typically,gait disturbance in iNPH patients is the initial and most prominent symptom,but motor impairments can also extend to upper extremity.The cerebrospinaluid(CSF)tap test(TT),in which the symptoms of iNPH patients are assessed before and after drainage of 30-50mL CSF by lumbar puncture,is a commonly used auxiliary test for predicting shunt responsiveness.Standard methods for determining the CSF TT response are based on the clinical impression of changes in gait after lumber puncture.iNPH patients who are unable to ambulate(e.g.,the patient is wheelchair bound)may not be able to comply with the gait evaluation but still benet from shunt placement.The grooved pegboard test(GPT)and symbol-digit modalities test(SDMT)are psychometric measures of upper extremity motor and psychomotor speed.Herein,we sought to identify whether these tests could be used to objectively assess responsiveness to the CSF TT.