Kyunghun Kang

Background and purpose: This study aimed to characterize structural alterations of the hippocampus associated with idiopathic normal-pressure hydrocephalus (INPH), and to explore their relationship with gait disturbances in affected patients. Methods: A total of 48 patients with INPH and 25 β-amyloid–negative healthy controls underwent MRI-based, vertex-wise three-dimensional hippocampal shape analysis. Additionally, all participants received 18F-florbetaben positron emission tomography to assess amyloid status. Results: Hippocampal shape analysis revealed marked bilateral deformation in the INPH group compared to controls. Both hippocampi exhibited elongation and narrowing, with the middle and posterior regions showing upward curvature, indicating vertical displacement from the hippocampal body to the tail. The normalized hippocampal volume was significantly smaller in INPH patients. No substantial volumetric or morphological differences were observed between amyloid-positive and amyloid-negative individuals within the INPH group. Notably, localized shape deformities correlated with performance on the Timed Up and Go and 10-meter walk tests, more prominently in the right hippocampus. Bilateral inward deformations at the superomedial tail and inferior body of the hippocampus were consistently linked to worse gait performance. Furthermore, smaller right normalized hippocampal volumes were negatively associated with gait test outcomes. Conclusion: These findings indicate that INPH is associated with characteristic hippocampal shape abnormalities. The observed associations between hippocampal morphology and gait disturbances suggest that the hippocampus may contribute to gait and postural control in INPH.

The optimal shunt strategy for adult posthemorrhagic hydrocephalus (PHH) remains uncertain. Although ventriculoperitoneal shunting (VPS) is widely used, it is associated with notable complications related to ventricular catheterization. Lumboperitoneal shunting (LPS) offers a less invasive alternative by avoiding ventricular access. This study aimed to systematically review and meta-analyze the complication profiles of LPS and VPS in adult PHH. PubMed, Embase, and Web of Science databases were systematically searched for original studies that reported postoperative complications in adults with PHH treated with LPS or VPS. Primary outcome was shunt-related complications; secondary outcomes included shunt-failure, obstruction, infection, and shunt complication in severe stage PHH. Two authors independently performed data extraction and quality assessment using the Joanna Briggs Institute Critical Appraisal Checklist. Pooled proportions were estimated using single-arm random-effects meta-analyses with restricted maximum likelihood and Freeman-Tukey double arcsine transformation, with back-transformation applied for reporting. The study protocol was registered in PROSPERO (CRD420251143570). Of 3,183 records screened, 10 studies comprising 1,410 patients met inclusion criteria. Overall evidence quality ranged from moderate to high. The pooled shunt complication proportion was 0.37 (95% CI, 0.30-0.45) for LPS and 0.24 (95% CI, 0.13-0.37) for VPS, with substantial heterogeneity observed among VPS cohorts (LPS: I²= 30.77%; VPS: I² = 88.09%). No significant differences were observed between the two groups for shunt failure, obstruction, infection, or shunt complication in severe stage PHH (P = 0.33, 0.56, 0.31 and 0.78, respectively). Subgroup analysis and meta-regression revealed an inverse association between age and shunt-related complications in LPS cohorts. Overall, LPS showed complication-related outcomes comparable to VPS in adult PHH; however, because the evidence is mostly based on observational and indirect comparisons, these findings should be interpreted with caution. Further comparative studies are required to more definitively evaluate the relative effectiveness and safety of LPS and VPS.

Objectives: This study investigated changes in speech characteristics across production phases during diadochokinetic (DDK) tasks to characterize speech motor features in Parkinson’s disease (PD). Unlike previous research that focused primarily on overall speech rate, this study examines articulatory transition ability by measuring intersyllabic transition times across segmented task phases.Methods: Twenty PD patients and twenty age- and gender-matched healthy elderly (HE) adults performed DDK tasks. In addition to the syllable repetition rate, intersyllabic transition times were quantified and compared across the early, middle, and late phases of the task.Results: First, in the alternating motion rate (AMR) tasks, there were no significant differences in the syllable repetition rates between the two groups; however, both groups showed significantly higher repetition rates for /pɑ/ compared to /kɑ/. Second, the PD group exhibited significantly lower syllable repetition rates than the HE group in the sequential motion rate (SMR) task. Third, in the AMR task, there were no significant differences in intersyllabic transition times across phases between the two groups. Fourth, in the SMR task, the PD group exhibited significantly longer intersyllabic transition times than the HE group; furthermore, both groups showed longer transition times in the middle phase compared to the early and late phases.Conclusion: Although the two groups showed comparable performance in single-syllable repetition tasks, the PD group exhibited specific deficits in tasks requiring transitions between different syllables. These findings suggest that measuring intersyllabic transition times in diadochokinetic tasks constitutes an important indicator of speech motor features in patients with Parkinson’s disease.

Objectives: To investigate the characteristics of hypokinetic dysarthria in Parkinson’s disease (PD), we compared and analyzed changes in temporal and articulatory speech characteristics occurring during the early and late phases of a paragraph reading task.Methods: Twenty PD patients at Hoehn and Yahr stage 2 and 20 age- and gender-matched healthy elderly adults (HE) performed a paragraph reading task. The entire paragraph was divided into early and late sections. Temporal indicators (reading rate, articulation rate, pause ratio, pause frequency) and articulatory indicators (consonant accuracy, speech intelligibility) were calculated. Mixed ANOVA was used to verify differences between groups and phases.Results: The PD group exhibited significantly slower reading and articulation rates compared to the HE group. The PD group exhibited a significant increase in pause frequency toward the late phase, which can be interpreted as a result of worsening under-articulation due to motor fatigue from sustained speech production. Furthermore, while the HE group showed no difference in consonant accuracy between phases, the PD group demonstrated a significant decrease in consonant accuracy in the late phase.Conclusion: PD patients exhibited a characteristic decline in reading endurance, marked by increased pausing frequency and reduced consonant accuracy toward the end of paragraphs. This suggests that the reduced communication efficiency in PD patients stems from deficits in the motor maintenance ability required to sustain speech accuracy. Therefore, clinical practice should emphasize dynamic assessment observing performance changes based on fatigue levels and intervention approaches aimed at improving speech endurance.

Objective : Lumboperitoneal shunt (LPS) surgery is a widely used treatment for normal pressure hydrocephalus (NPH), especially in East Asia. Although LPS surgery has been widely studied internationally, large-scale data from the Republic of Korea are limited. This study aimed to evaluate clinical outcomes and complications of LPS surgery in NPH patients, with particular focus on anesthesia type and valve pressure management strategies.Methods : A retrospective review was conducted of 244 patients with NPH who underwent LPS surgery between February 2020 and February 2025. Valve pressures were initially set at the highest level and gradually adjusted downward based on clinical response. Functional outcomes—including the modified Rankin scale (mRS), timed up and go (TUG), 10-m gait test, and Mini-Mental State Examination (MMSE)—were assessed at 1 year and followed for up to 4 years. Complications were categorized by type and whether surgical intervention was required.Results : Among 244 patients, 119 completed at least 1 year of follow-up. At 1 year, 53.8% of patients showed mRS improvement, and 66.4% demonstrated gait improvements (TUG and 10-m walk). Stable or improved function was observed in 93.3% of patients. MMSE scores did not show significant change. The overall complication rate was 16.8%, with 11.1% requiring surgical revision, primarily for chronic subdural hematoma and catheter-related issues. No surgery-related mortality occurred, but three patients (1.2%) died from falls despite improved gait, underscoring the need for fall prevention. The adoption of an initial high-pressure setting reduced overdrainage-related complications, contributing to a decreased annual revision rate of 5.6%.Conclusion : A retrospective study showed that LPS surgery with local anesthesia is effective for NPH patients, demonstrating favorable functional outcomes and acceptable complications. Using higher initial valve pressures significantly decreased the need for revision surgeries and complications related to overdrainage.

Lee YJ, et al. Yonsei Med J. 2026 Jan;67:e3. https://doi.org/10.3349/ymj.2025.0156

Recent studies have highlighted the occurrence of reduced striatal signal intensity on dopamine transporter (DAT) scans in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of our study was to investigate whether the extent of symptom improvement after a CSF tap test (TT) differs between iNPH patients with reduced striatal DAT uptake and those with normal uptake. We conducted gait analysis on 44 patients with iNPH who underwent DAT scans at Seoul National University Bundang Hospital (SNUBH) and Kyungpook National University Chilgok Hospital (KNUCH) both before and after a CSF TT. A positive response to the TT was defined as an improvement in walking speed of 10% or greater compared with baseline. We compared TT response rates between iNPH patients with and without striatal dopaminergic deficit using logistic regression models, with the medical institution (SNUBH, KNUCH) as a stratification variable. Among 36 patients without striatal dopaminergic deficit, 22 patients (61.11%) exhibited a response after the TT, whereas among 8 patients with striatal dopaminergic deficit, 5 patients (62.5%) exhibited a response after the TT. The response rate after TT was not significantly different between the iNPH patients with and without striatal dopaminergic deficit (odds ratio 0.46; p value = 0.4048). Our findings suggest that gait improvement after a CSF TT in patients with iNPH remains consistent regardless of the presence or absence of reduced striatal DAT uptake. Further research involving a larger cohort is necessary to validate these observations.

Objective: The aims of the study were to investigate differences in cortical mean diffusivity (MD) among idiopathic normal-pressure hydrocephalus (INPH) patients, Alzheimer’s disease (AD) patients, and healthy controls, and to analyze mean MD among INPH and AD groups in INPH-specific areas showing distinctive cortical MD changes for distinguishing INPH from AD.Methods: Forty-two INPH patients, 51 AD patients, and 23 healthy controls were imaged with MRI, including diffusion tensor imaging MR images, for surface-based analysis across the entire brain.Results: Compared with healthy controls, INPH patients showed a statistically significant reduction in MD in the high convexity of the frontal, parietal, and occipital cortical regions. We designate these clusters of lower MD as INPH MD LOW ROI. Additionally, a significant increase in MD, mainly in the ventromedial frontal cortex, ventrolateral frontal cortex, supramarginal gyrus, and temporal cortical regions, was observed in the INPH group relative to the control group. We designate these clusters of higher MD as INPH MD HIGH ROI. INPH patients showed significantly lower mean MD in INPH MD LOW ROI and higher mean MD in INPH MD HIGH ROI than AD. The mean MD of INPH MD LOW ROI had an AUC of 0.857 for differentiating INPH from AD.Conclusion: A distinctive pattern of cortical MD changes was found in INPH patients, and cortical regions of low MD distinguished INPH from AD with good diagnostic sensitivity and specificity. Our findings suggest microstructural changes in cortical integrity can help differentiate INPH and AD in elderly patients.

Introduction In patients with idiopathic normal pressure hydrocephalus (iNPH), the characteristics of static steady-state balance disturbance are not as well understood as those related to gait. This study aimed to investigate differences in center of pressure (COP) parameters between patients with iNPH and age-matched healthy controls. Methods A total of 56 patients diagnosed with probable iNPH, who responded positively to cerebrospinal fluid tap test (CSFTT), along with 25 age-matched healthy controls, were enrolled. Prior to the CSFTT, COP measurements were taken using a force plate while participants stood quietly with eyes open (EO) and eyes closed (EC). We calculated the values of mediolateral (ML) and anteroposterior (AP) directions and ML/AP ratio in terms of the velocity of COP (vCOP), the standardized COP path length (Std_vCOP), and the peak power spectral density (PSD) at 0–0.5 Hz and 0.5–1.0 Hz. Additionally, we calculated the average distance from the COP center (Dist_COP) and the base of support (BOS). A Mann–Whitney U test with Bonferroni correction was used to compare differences between healthy controls and patients with iNPH under each visual condition (EO vs. EC). Results There were no significant differences in gender, age, height, and weight between the healthy controls and the patients with iNPH. Patients with iNPH demonstrated greater spontaneous sway in the ML direction of vCOP (p < 0.001), increased variability in both ML and AP directions of Std_vCOP (p < 0.001 for both), a larger Dist_COP (p < 0.001) and BOS (p < 0.001) in the EC condition. Under the EO condition, patients with iNPH exhibited a significantly higher ML/AP ratio (p < 0.001) and larger BOS (p < 0.001). Furthermore, peak PSD at 0–0.5 Hz, reflecting low-frequency oscillations, was more pronounced in the ML direction and in the ML/AP ratio (p < 0.001 for both under EO), as well as in the AP direction (p < 0.001 under EC) in patients with iNPH. However, no significant differences were observed in the high-frequency oscillations (0.5–1.0 Hz). Conclusions These findings suggest that patients with iNPH exhibit distinct COP patterns, particularly greater variability in the ML direction during quiet standing. In contrast, the AP direction appears to be more influenced by visual conditions when compared to healthy controls. This result highlights the potential need for tailored balance training in patients with iNPH.

Objectives: The aim of this study was to determine whether multifaceted analyses of a lexical retrieval task can provide meaningful information for the differential diagnosis of Alzheimer’s disease (AD), normal pressure hydrocephalus (NPH), and Parkinson’s disease (PD).Methods: A total of 41 patients diagnosed with AD, NPH, or PD and 16 healthy elderly adults (HE) were tested on a lexical retrieval task. Response scores, response times, error types, and the percentage of errors resolved were compared across groups, and a correlation analysis with the Korean Mini-Mental State Examination (K-MMSE) was performed.Results: First, the AD, NPH, and PD groups had significantly fewer correct responses and significantly more incorrect responses than the HE group. The PD group made significantly more incorrect responses than the AD group. Second, the AD, NPH, PD group had significantly slower reaction times for correct responses than the HE group. Third, all four groups showed significantly more semantic errors than other error types, and the least were mixed errors. Fourth, the three patient groups were significantly less able to monitor and correct errors than the HE group. Fifth, the K-MMSE score was significantly positively correlated with the number of correct responses and negatively correlated with the number of incorrect responses, semantic errors, and unrelated errors.Conclusion: We suggest that the lexical retrieval task can be effectively used to screen patients with AD, NPH, and PD from HE, and explore its potential for differential diagnosis.