Profiling iNPH features through cluster analysis: an aid for clinical suspicion and diagnosis.

PURPOSE: Idiopathic Normal Pressure Hydrocephalus (iNPH) is a neurological syndrome defined by gait disturbance, cognitive impairment and urinary incontinence. However, its clinical presentation can vary widely due to overlapping syndromes and common comorbidities in older adults. This study aims to provide practical guidance to aid in the clinical suspicion and support the diagnostic and therapeutic processes for these patients. METHODS: Six quantitative variables regarding clinical, functional, and demographic aspects were considered for a large sample of patients with diagnosed iNPH. Principal component analysis (PCA) was adopted to define the main dimensions explaining the variability of the phenomenon. Then, two clusters of iNPH patients were described. RESULTS: 178 patients were included in the analysis. The PCA produced two dimensions covering 61.8% of the total variability. The first one relied mainly on both clinical (mRS, iNPHGs) and functional (TUG, Tinetti) variables, while the second one was represented mainly on the demographic pattern (age and education). Cluster analysis depicted two main groups of patients. Cluster n.1 is composed of individuals who are older, more disabled, with poor functional performances, and highly symptomatic. Cluster n.2 patients are slightly younger, more educated, fitter, and with more nuanced clinical aspects. CONCLUSIONS: Profiling iNPH patients using quantitative variables and cluster analysis can help identify distinct characteristics of these patients, aiding in the guidance of both medical and surgical interventions.

Gait apraxia evaluation in normal pressure hydrocephalus using inertial sensors. Clinical correlates, ventriculoperitoneal shunt outcomes, and tap-test predictive capacity.

BACKGROUND: Idiopathic normal pressure hydrocephalus (iNPH) is a neurological condition with gait apraxia signs from its early manifestation. Ventriculoperitoneal shunt (VPS) is a surgical procedure available for treatment. The Cerebrospinal fluid Tap Test (CSF-TT) is a quick test used as selection criterion for VPS treatment. Its predictive capacity for VPS outcomes is still sub judice. This study is aimed to test the hypothesis that wearable motion sensors provide valid measures to manage iNPH patients with gait apraxia. METHODS: Forty-two participants of the Bologna PRO-Hydro observational cohort study were included in the analyses. The participants performed the Timed Up and Go (TUG) and the 18 m walking test (18mW) with inertial sensors at baseline, three days after the CSF-TT, and six months after VPS. 21 instrumental variables described gait and postural transitions from TUG and 18mW recordings. Furthermore, participants were clinically assessed with scales (clinical variables). We tested the hypothesis by analysing the concurrent validity of instrumental and clinical variables, their individual- and group-level responsiveness to VPS, and their predictive validity for VPS outcomes after CSF-TT. RESULTS: The instrumental variables showed moderate to high correlation with the clinical variables. After VPS, most clinical and instrumental variables showed statistically significant improvements that reflect a reduction of apraxic features of gait. Most instrumental variables, but only one clinical variable (i.e., Tinetti POMA), had predictive value for VPS outcomes (significant adjusted R2 in the range 0.12-0.70). CONCLUSIONS: These results confirm that wearable inertial sensors may represent a valid tool to complement clinical evaluation for iNPH assessment and prognosis.