Long-term 4 Years Follow-up Study of 482 Patients Who Underwent Shunting for Idiopathic Normal Pressure Hydrocephalus -Course of Symptoms and Shunt Efficacy Rates Compared by Age Group-

Abstract

A total of 482 operated idiopathic normal pressure hydrocephalus (iNPH) patients were divided into those aged <80 years at the time of surgery (group A: 400 cases; and male-to-female ratio, 259:141) and ≥80 years (group B: 82 cases; male-to-female ratio, 43:39) and comparatively investigated based on the following variables: (1) temporal changes in shunt efficacy rates, and (2) temporal changes in each symptom, including the patient’s fall frequency and preoperative modified Rankin Scale (mRS) score and during follow-up at 3, 6 months, 1–4 years postoperatively. (1) The shunt efficacy rates at 3 months and 4 years postoperatively were 93% and 82%, respectively, in group A and 92.3% and 70.7%, respectively, in group B. This demonstrates a decrease in shunt efficacy at 4 years postoperatively, regardless of the persistence of shunt function or adjustments in setting pressure. This trend was particularly observed in group B. In group A, 41 (9.8%) cases had decreased efficacy rate, compared with 21 (25.6%) cases in group B, which occurred due to complications with an extracranial or intracranial disease. (2) Gait disturbance ( G ) and urinary incontinence ( U ) showed signs of improvement in the early postoperative stage, while dementia ( D ) and mRS score began to gradually improve from 6 months postoperatively. Patient’s fall frequency tended to become higher until 6 months postoperatively than the preoperative rate. In group A, symptom improvement was comparatively maintained until 4 years postoperatively, while in group B, all symptoms and mRS tended to gradually deteriorate beginning at 3 years postoperatively.

Normal Pressure Hydrocephalus Associated with Alzheimer's Disease

“…From a methodological point of view, it should be pointed out that the data of this study were gathered during the diagnostic work‐up in patients with suspected NPH to establish the diagnosis and to predict shunt outcome 7,10 . Importantly, the lumbar opening pressure was in the normal range, 27 apart from one patient in each group having a pressure 2cm H 2 O above the upper limit.…”

“…However, the clinical appearance can vary among patients such that the typical triad is present in <60% of the patients 7,8 . Also, the variable responses to a spinal tap over a few years after shunting provoked questions regarding of the existence of idiopathic NPH as a clinical entity 9,10 . In particular, it was argued that patients with progressive dementia, such as Alzheimer's disease, Parkinson's syndrome, or subcortical arteriosclerotic leukencephalopathy, might present with similar symptoms and even show a transient clinical improvement upon a spinal tap.…”

Deficient visuomotor hand coordination in normal pressure hydrocephalus

“…From a methodological point of view, it should be pointed out that the data of this study were gathered during the diagnostic work-up of NPH to establish the diagnosis and to predict putative shunt outcome [ 7 , 10 ]. Importantly, one of the starting points of our study was to assess the cognitive deficits and the impairment of gait in a quantitative fashion to provide observer-independent and reliable measures of the neurological improvement potentially brought about by the spinal tap.…”

Gaps, Controversies, and Proposed Roadmap for Research in Normal Pressure Hydrocephalus

“…Symptoms of iNPH in older patients might be thought to be related to other medical disorders and therefore not recognized as such. Also, older patients tend to benefit less from shunt than younger ones 57 …”