====== Idiopathic normal pressure hydrocephalus diagnosis ====== {{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1Je_9-UNj9krj-xZmwyTSw2bXpvOoqXwi46YogKoHDHqAw8U12/?limit=15&utm_campaign=pubmed-2&fc=20230704135332}} ---- ---- Diagnosis is based on the evaluation of [[Idiopathic normal pressure hydrocephalus clinical features]] combined with an [[MRI]] assessment, evaluation of [[cerebrospinal fluid dynamics]] by different methods such as a [[tap test]], [[lumbar infusion test]] (LIT), and [[External lumbar cerebrospinal fluid drainage]] (ELD). ---- [[Screening]] for [[idiopathic normal pressure hydrocephalus]] in the elderly presenting after [[fall]]s can possibly identify iNPH patients in the earlier stage who may benefit more from surgical treatments ((Oike R, Inoue Y, Matsuzawa K, Sorimachi T. Screening for idiopathic normal pressure hydrocephalus in the elderly after falls. Clin Neurol Neurosurg. 2021 Apr 24;205:106635. doi: 10.1016/j.clineuro.2021.106635. Epub ahead of print. PMID: 33906000.)). ---- Patients often present to the [[neurosurgeon]] frustrated and desperate after a long preoperative course. It is important to acknowledge the uncertainty regarding [[Idiopathic normal pressure hydrocephalus diagnosis]] ((Subramanian HE, Mahajan A, Sommaruga S, Falcone GJ, Kahle KT, Matouk CC. The subjective experience of patients undergoing shunt surgery for idiopathic normal pressure hydrocephalus. World Neurosurg. 2018 Jul 4. pii: S1878-8750(18)31425-6. doi: 10.1016/j.wneu.2018.06.209. [Epub ahead of print] PubMed PMID: 29981467. )). There is no accurate test for diagnosing [[normal pressure hydrocephalus]] or for screening for patients who will benefit from shunt surgery. Shunting is possibly effective in iNPH (96% chance subjective improvement, 83% chance improvement on timed walk test at 6 months) (3 [[Class III]]). Serious adverse event risk was 11% (1 Class III). Predictors of success included elevated Ro (1 Class I, multiple [[Class II]]), impaired cerebral blood flow reactivity to acetazolamide (by SPECT) (1 [[Class I]]), and positive response to either [[External lumbar cerebrospinal fluid drainage]] (1 Class III) or repeated lumbar punctures. Age may not be a prognostic factor (1 Class II). Data are insufficient to judge efficacy of radionuclide cisternography or aqueductal flow measurement by MRI. ---- There is limited Class I evidence that impaired cerebral blood flow (CBF) reactivity to acetazolamide is a predictor of successful CSF shunting, but Single-photon emission computed tomography (SPECT) is not a practical screening tool for NPH. ===== Imaging ===== [[Idiopathic normal pressure hydrocephalus Imaging]] see [[Disproportionately enlarged subarachnoid space hydrocephalus]]. ---- Fewer [[centrum semiovale]] [[enlarged perivascular space]]s may be a [[diagnostic biomarker]] for [[idiopathic normal pressure hydrocephalus diagnosis]]. This pattern may be caused by mechanical [[obstruction]] due to upward displacement of the brain leading to reduced [[glymphatic]] clearance ((Switzer AR, Graff-Radford J, Gunter JL, Elder BD, Jones DT, Huston J, Jack CR, Cogswell PM. Patients with normal pressure hydrocephalus have fewer enlarged perivascular spaces in the centrum semiovale compared to cognitively unimpaired individuals. Clin Neurol Neurosurg. 2024 Jan 17;237:108123. doi: 10.1016/j.clineuro.2024.108123. Epub ahead of print. PMID: 38262154.)). ===== Psychomotor Tasks ===== Although gait is the primary indicator for treatment candidacy and outcome, additional monitoring tools are needed. [[Line Tracing Test]] (LTT) and Serial Dotting Test (SDT), two psychomotor tasks, have been introduced as potential outcome measures ((Rossetti MA, Piryatinsky I, Ahmed FS, Klinge PM, Relkin NR, Salloway S, Ravdin LD, Brenner E, Malloy PF, Levin BE, Broggi M, Gavett R, Maniscalco JS, Katzen H. Two Novel Psychomotor Tasks in Idiopathic Normal Pressure Hydrocephalus. J Int Neuropsychol Soc. 2016 Mar;22(3):341-9. doi: 10.1017/S1355617715001125. Epub 2016 Jan 28. PubMed PMID: 26817685. )). ===== Lumbar puncture for idiopathic normal pressure hydrocephalus diagnosis ===== see [[Lumbar puncture for Idiopathic normal pressure hydrocephalus diagnosis]]. ===Pressure recording=== see [[Idiopathic normal pressure hydrocephalus intracranial pressure monitoring]]. [[Alzheimer disease]] (AD)-related pathology was assessed in cortical biopsy samples of 111 patients with idiopathic normal-pressure hydrocephalus. Alzheimer disease hallmark lesions [[amyloid beta]] (Aβ) and hyperphosphorylated [[tau protein]] (HPtau)-were observed in 47% of subjects, a percentage consistent with that for whole-brain assessment reported postmortem in unselected cohorts. Higher-immunostained area fraction of AD pathology corresponded with lower preoperative [[mini mental state examination]] scores. Concomitant Aβ and HPtau pathology, reminiscent of that observed in patients with AD, was observed in 22% of study subjects. There was a significant correlation between Aβ-immunostained area fraction in tissue and Aβ42 (42-amino-acid form of Aβ) in [[cerebrospinal fluid]] (CSF). Levels of Aβ42 were significantly lower in CSF in subjects with concomitant Aβ and HPtau pathology compared with subjects lacking pathology. Moreover, a significant correlation between HPtau-immunostained area fraction and HPtau in CSF was noted. Both HPtau and total tau were significantly higher in CSF in subjects with concomitant Aβ and HPtau pathology compared with subjects lacking pathology. The 42-amino-acid form of Aβ (Aβ42) and HPtau in CSF were the most significant predictors of the presence of AD pathology in cortical biopsies. Long-term follow-up studies are warranted to assess whether all patients with idiopathic normal-pressure hydrocephalus with AD pathology progress to AD and to determine the pathologic substrate of idiopathic normal-pressure hydrocephalus ((Elobeid A, Laurell K, Cesarini KG, Alafuzoff I. Correlations Between Mini-Mental State Examination Score, Cerebrospinal Fluid Biomarkers, and Pathology Observed in Brain Biopsies of Patients With Normal-Pressure Hydrocephalus. J Neuropathol Exp Neurol. 2015 May;74(5):470-479. PubMed PMID: 25868149. )). ===== Biopsy ===== [[Biopsy for Idiopathic normal pressure hydrocephalus diagnosis]]. ===== Biomarkers ===== [[Idiopathic normal pressure hydrocephalus Cerebrospinal fluid biomarkers]]