BackgroundSensory impairment has been associated with cognitive decline and dementia. However, endpoint-based longitudinal analyses often cannot determine whether sensory impairment is related to early cognitive deterioration, reduced cognitive recovery, dementia progression, or mortality-related study exit.MethodsWe analyzed 2004–2022 Health and Retirement Study data using a continuous-time multistate Markov model. Four states were defined: normal cognition, cognitive impairment no dementia (CIND), dementia, and death. The analytic cohort included 18,292 participants, and 16,083 were included in the primary complete-case adjusted model. Baseline self-reported sensory status was classified as no impairment, visual impairment only, hearing impairment only, or dual sensory impairment. Primary models adjusted for age, sex, education, wealth, depressive symptoms, and chronic disease count; sensitivity analyses included time-varying and lagged exposures, inverse-probability weighting, and expanded confounding adjustment.ResultsCompared with no sensory impairment, visual impairment only, hearing impairment only, and dual sensory impairment were associated with faster transitions from normal cognition to CIND. The corresponding HRs were 1.18 (95% CI, 1.10–1.27), 1.16 (95% CI, 1.07–1.25), and 1.37 (95% CI, 1.26–1.50). Visual impairment only and dual sensory impairment were also associated with slower transitions from CIND to normal cognition, with HRs of 0.79 (95% CI, 0.72–0.86) and 0.84 (95% CI, 0.75–0.94), respectively. Associations with CIND-to-dementia progression and mortality-related transitions were less consistent. Time-varying, lagged, weighted, and expanded-confounding analyses supported the same early-transition pattern.ConclusionSensory impairment, particularly dual sensory impairment, was most consistently associated with early cognitive deterioration and reduced cognitive recovery. It was not consistently associated with higher dementia progression or mortality transition rates. Death-inclusive multistate modeling may help identify where potentially modifiable sensory impairment is related to cognitive ageing trajectories.
Alzheimer's disease (AD) is associated with progressive cognitive decline and altered brain functional activity, yet objective and interpretable electrophysiological indicators remain insufficiently established. Resting-state electroencephalography (EEG) offers a low-cost and clinically accessible candidate, provided that the analysis is validated at the subject level and remains interpretable. This study evaluated an interpretable resting-state EEG framework for distinguishing AD patients from healthy control (HC) subjects. A total of 63 participants (36 AD and 27 HC) from a publicly available dataset were included. Subject-level spectral and nonlinear complexity features were extracted from 19 preprocessed scalp channels; missing-value imputation, feature screening, redundancy pruning, scaling, and model fitting were carried out within each fold of leave-one-subject-out cross-validation. Four linear classifiers were compared, and Ridge Logistic regression was retained for out-of-fold SHAP interpretation because of its balanced hard-label performance and direct compatibility with Linear SHAP. Ridge Logistic regression achieved an exploratory AUC of 0.912 (accuracy = 0.857, sensitivity = 0.778, specificity = 0.963) under a non-nested validation design. Across 30 independently balanced epoch resamples, mean AUC was 0.887 ± 0.020; using all accepted epochs yielded AUC = 0.917. SHAP analysis indicated that the classifier drew jointly on posterior α activity, frontal and temporal θ power, the θ/α ratio, and slow/fast ratio features. A classifier-independent microstate analysis revealed reduced putative Class B occurrence, increased putative Class C and Class D duration, and six FDR-corrected off-diagonal transition differences in AD; the three temporal effects persisted across repeated K = 4 initializations and matched K = 3–6 solutions. These findings suggest that resting-state EEG can provide non-invasive and interpretable information about AD-related functional alterations, pending validation in larger, independent cohorts.
IntroductionDespite growing interest in age-related cortical mechanisms of postural control, heterogeneity across studies has limited the synthesis of existing evidence. This systematic review aimed to (1) characterize age-related alterations in cortical activity during standing balance tasks with sensory, cognitive, and mechanical challenges; (2) examine the association between cortical activity and postural sway; and (3) characterize the current methodology of assessing cortical activity during standing balance tasks in older adults (OA).MethodsRelevant research articles were identified through systematic searches of MEDLINE, EMBASE, PsycINFO, and CINAHL from inception to October 8, 2025. Eligible studies measured cortical activity during standing balance under sensory, cognitive, and mechanical challenges using electroencephalography (EEG) or functional near-infrared spectroscopy (fNIRS). We used the Standard Quality Assessment Criteria for quantitative studies for quality assessment.ResultsThirty-seven studies with a total of 1,302 participants, including 788 OA (60.5%), were included. Most studies (n = 29, 78.4%) demonstrated strong methodological quality. Evidence suggested diminished task-dependent cortical modulation and weaker associations between cortical activity and postural sway as task demands increased in OA compared to younger adults (YA). OA tended to show prolonged latencies and reduced amplitudes following mechanical perturbation. Nevertheless, some studies also suggested that OA may still recruit additional cortical resources under specific task conditions, which may reflect compensatory processes.DiscussionThis systematic review indicates that aging may be associated with diminished task-dependent cortical modulation, weaker associations between cortical activity and postural sway, and delayed sensorimotor processing during challenging balance tasks. These findings provide a foundation for future studies aimed at clarifying age-related cortical mechanisms of postural control during standing balance.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD420251159695.
Over 95% of Alzheimer's disease (AD) is caused by a complex mixture of genetic and environmental factors. This is called sporadic AD or late-onset AD, and much of its pathological mechanisms remain unclear. There is growing evidence indicating that the viral infection, such as herpes simplex virus type 1 (HSV-1), triggers and worsens the AD progression in combination with the APOE4 genotype in AD patients. The innate immunity of host cells produces proinflammatory cytokines, which further drive neuroinflammation in the brain. Concurrently, Aβ and phosphorylated tau could entrap foreign pathogens such as HSV-1 according to the "antimicrobial protection hypothesis of AD," and accelerate the progression of AD. In this review, growing evidence ranging from HSV-1 infection to the AD progression via the accumulation of Aβ and tau, and neuroinflammation is explored.
Neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD) share progressive memory impairment, yet their upstream pathologies differ. This review synthesizes evidence across these disorders to frame memory decline through engram ensembles and proposes an excitability-vulnerability tradeoff, in which the physiological requirements for engram function, including elevated excitability, synaptic plasticity, and coordinated network activity, also increase sensitivity to synaptic stress, network disruption, and inflammatory perturbations. We summarize disease-related pathological cascades. To date, AD has the most robust body of direct experimental evidence linking pathology to impaired engram function. Solid experimental findings demonstrate that amyloid-β (Aβ)/tau causes hippocampal engram inaccessibility in AD. For PD and HD, inferences drawn from synaptic and circuit dysfunction suggest that α-synuclein (α-syn) pathology and dopaminergic loss may disrupt striatal ensembles, and mutant huntingtin (mHTT) presumably impairs striatocortical coordination. We further integrate a shared amplification route in which microglial activation and complement-linked synaptic remodeling weaken memory-relevant connectivity and reduce cue-driven ensemble reinstatement. This mechanism is well validated in AD, while supporting evidence for PD and HD remains largely indirect. Finally, we outline a translational roadmap that integrates circuit-targeted delivery, engram-relevant clinical endpoints, and scalable neuromodulation, supported by human neuronal-glial molecular profiling to guide mechanism-informed combination strategies. Importantly, these multi-tiered therapeutic approaches act on the full spectrum of neural cells rather than only memory engram ensembles, and cognitive rescue arises from a multifactorial regulatory process involving both global neuroprotection and ensemble stabilization. We also systematically discuss key limitations of current engram research, including methodological heterogeneity in engram labelling tools, interspecies translational barriers, and substantial clinical obstacles for optogenetic and circuit-based therapeutic applications.
Restless Legs Syndrome (RLS) is a sensorimotor neurological disorder characterized by an irresistible urge to move the lower limbs. Although traditional paradigms attribute its pathogenesis to peripheral iron deficiency, many clinically diagnosed patients present with normal peripheral iron indicators yet exhibit central iron homeostatic dysregulation. This discrepancy highlights a distinct decoupling between peripheral iron stores and central iron availability. The RLS-associated iron metabolic impairment is inherently a complex pathological network orchestrated by multidimensional processes, including intestinal absorption, systemic distribution, blood-brain barrier (BBB) transport, and intracellular utilization. Crucially, gut dysbiosis-induced low-grade enterogenous inflammation may activate the IL-6/hepcidin pathway, thereby sequestering systemically available iron; this mechanism represents a pivotal upstream driver of central iron insufficiency. Consequently, impaired cerebral iron utilization disrupts the physiological equilibrium of neurotransmitter systems—namely dopamine, adenosine, and glutamate—ultimately triggering the sensorimotor symptoms and sleep disturbances characteristic of RLS. Therefore, clinical management should shift away from relying solely on isolated peripheral indicators toward implementing individualized iron supplementation phenotyped by specific absorption, distribution, or transport mechanisms. Looking forward, microecological interventions utilizing prebiotics or short-chain fatty acids (SCFAs) to mitigate systemic inflammation and ameliorate the intestinal environment hold substantial promise as a synergistic therapeutic strategy for RLS.
Parkinson’s disease (PD) is a heterogeneous neurodegenerative disorder marked by diverse motor and non-motor symptom profiles. Traditional symptom-based subtyping shows limited stability and lacks clear biological grounding. Integrating magnetic resonance imaging (MRI) with machine learning (ML) offers a promising avenue for defining biologically informed PD subtypes. This narrative review synthesizes evidence from MRI-based subtyping studies that used structural (T1-weighted), diffusion, functional, or multimodal MRI features as primary inputs for unsupervised or hybrid ML approaches to derive PD subtypes and outlines key methodological challenges and future translational needs. T1-weighted MRI studies consistently identify two to three subtypes characterized by distinct patterns of cortical and subcortical atrophy associated with variation in motor and non-motor symptoms. Although fewer in number, diffusion MRI studies have identified microstructural heterogeneity in PD. However, the findings remain heterogeneous and preliminary, and a stable subtyping framework has yet to be established. Multimodal MRI approaches show that combining modalities provides complementary insights into the neurobiology underlying PD heterogeneity but require further validation. Collectively, MRI-based subtyping shows promise for mapping clinical variability onto neuroanatomical patterns. At present, these subtypes are best viewed as research constructs that illuminate disease variability rather than clinical diagnostic tools. Translation into clinical practice will require addressing critical methodological gaps to achieve the reproducibility and prognostic utility necessary for precision medicine.
The high prevalence and adverse impact of delirium in critically ill patients necessitate a deeper understanding of its mechanisms. This review explores the pivotal interplay between systemic inflammation and delirium, examining how insults like age, pain and surgery orchestrate neuroinflammation and delirium through microglial activation and blood-brain barrier disruption. Our synthesis identifies a spectrum of inflammatory and neuronal injury biomarkers with prognostic value and evaluates the burgeoning field of anti-inflammatory pharmacotherapy. We conclude that bridging this mechanistic knowledge to clinical practice via biomarker-driven trials is essential for developing effective interventions against delirium.
BackgroundNon-motor symptoms (NMS) are highly prevalent in Parkinson’s disease (PD) and are major determinants of declining quality of life (QoL), yet traditional statistical approaches are insufficient to capture the complex interactions between NMS and QoL. Network analysis offers a promising alternative for exploring these interactions.ObjectiveTo construct a joint network of non-motor symptoms (NMS) and quality of life (QoL) in patients with Parkinson’s disease (PD), identify core and bridge nodes, and inform precision nursing interventions.MethodsA convenience sample of 342 PD patients was recruited between January and June 2026 from the PD specialty outpatient clinic and neurology inpatient wards of a tertiary specialized hospital in Tianjin, and investigated using the Non-Motor Symptoms Scale (NMSS) and the Parkinson’s Disease Questionnaire-39 (PDQ-39). A joint network model was constructed via network analysis, and network structures were compared between early- and mid-to-late-stage patients.ResultsNMSS6 gastrointestinal symptoms (Str = 1.027), PDQ5 social support (Str = 0.995), and PDQ6 cognition (Str = 0.992) were the core nodes of the joint network based on strength centrality. PDQ6 cognition (Bridge Str = 0.326) and NMSS3 mood/cognition (Bridge Str = 0.260) were the key bridge symptoms linking NMS and QoL. Mobility and social support showed the highest expected influence (EI = 0.960 and 0.939, respectively). The overall network structure differed significantly between early-stage and mid-to-late-stage patients (p = 0.004), whereas global network strength did not; after correction for multiple comparisons.ConclusionComplex associations exist between NMS and QoL in PD patients and are reorganized across disease stages; gastrointestinal symptoms, cognition, and social support represent candidate targets for future longitudinal and interventional research.
Oxidative stress, iron dyshomeostasis, and chronic neuroinflammation are the principal mechanisms involved in the progression of central nervous system (CNS) disorders, which are a significant source of death and chronic disability worldwide. This review focuses on understanding the mechanistic relationship between ferroptosis and neuroinflammation in central nervous system (CNS) disorders, which involves the molecular mechanisms, their role in the pathogenesis of the disease, and therapeutic opportunities available. Ferroptosis is a regulated form of cell death triggered by iron-catalyzed lipid peroxidation, glutathione depletion and inactivation of glutathione peroxidase 4 (GPX4), resulting in neuronal injury. The increased generation of ROS in the cell due to the presence of excess iron catalyzes Fenton chemistry, which leads to lipid peroxidation of the cell membrane and ferroptotic cell death, and damage-associated molecular patterns originating from the ferroptotic cell death promote the activation of NF-κB-dependent inflammatory signaling pathways and inflammasome formation. Excessive dysregulations involving the hepcidin-ferroportin axis, DMT1–transferrin transport, ferritin–NCOA4-mediated ferritinophagy, and regulatory pathways like Nrf2, IRP/IRE, and SIRT1 intensify oxidative stress, ferroptosis and neuroinflammation in neurodegenerative and acute CNS disorders. The role of several key molecular mediators such as SIRT1, Nrf2, NF-κB, iNOS/NO●, and COX-2 in connecting ferroptotic and inflammatory signaling pathways is also discussed in this review. This understanding of the mechanism of these players gives a mechanistic framework for the development of targeted therapeutic and nutritional interventions to reduce neuronal damage and help slow the progression of CNS disorders.
About 60% of the individuals living with Alzheimer’s disease (AD) in the United States are women. Increasing evidence points to a role for sex hormones, especially estrogen, in making women more vulnerable to AD than men. Several brainstem signaling pathways, as well as multiple neuropeptide modulators and their receptors, are implicated in AD pathology and therapeutic possibilities. However, there is limited research evaluating how the modulatory effects of sex hormones on mood and cognition interact with these brainstem systems. This review seeks to examine possible connections between the nucleus incertus (NI) relaxin-3/relaxin-family peptide receptor 3 (RLN3/RXFP3) system and sex hormone influences in AD to encourage further investigation into how sex hormones may modulate this pathway and contribute to sex differences in disease risk and progression. Understanding how hormone-based interventions, such as hormone replacement therapy (HRT) and hormonal contraceptives (HC), affect NI RLN3/RXFP3 signaling may provide novel insights into how these treatments can slow AD-associated cognitive decline. It is hoped that this data and concept synthesis will drive detailed investigations of these circuits and support the development of sex/gender-informed therapeutic strategies that better reflect the heterogeneity of AD dementia.
BackgroundParkinson’s disease (PD) is a progressive neurodegenerative disorder with motor and non-motor manifestations. Exercise is increasingly integrated into the management of people with PD, yet the literature spans diverse intervention modalities, outcome domains, and mechanism-related topics.ObjectiveTo characterize publication growth, global collaboration, article types, keyword networks, thematic evolution, outcome domains, and emerging research fronts in exercise intervention research for PD.MethodsEnglish-language original articles and reviews indexed in the Web of Science Core Collection and Scopus from database inception to June 15, 2026, were retrieved. After eligibility screening, cross-database merging, and removal of duplicate and bibliographically incomplete records, 6,542 publications were included. Bibliometric analyses were conducted in R version 4.5.3 using the bibliometrix package and related R packages. The analyses included annual publication and citation trends, article-type distribution, geographic collaboration, keyword co-occurrence, thematic evolution, clinical and functional outcome mapping, citation structure, recent keyword bursts, and exploratory forecasting.ResultsPublication output increased substantially after 2010, with original articles consistently comprising the majority of the literature and reviews increasing over time. Research output was concentrated in North America and Europe, while contributions from Asia expanded rapidly. Gait, rehabilitation, balance, motor function, and quality of life constituted the persistent thematic core. The gait–rehabilitation–balance family remained the largest thematic family in 2022–2026, accounting for 65.6% of publications, whereas the cognition–mood–quality-of-life family increased to 41.9%. Gait was the most frequently represented outcome, followed by balance, cognition, quality of life, motor function, and falls. Recent growth was observed in cognition, depression and anxiety, sleep, fatigue, evidence synthesis, technology-assisted rehabilitation, and exercise-dose optimization. Highly cited eligible publications primarily addressed exercise effectiveness, Tai Chi, cueing, treadmill and aerobic exercise, balance and resistance training, physical therapy, motor learning, and exercise-related neuroplasticity.ConclusionExercise research in PD has progressed from basic functional rehabilitation toward a broader framework integrating mobility, non-motor outcomes, technology-assisted delivery, and individualized exercise prescription. Future research should improve the reporting of intervention components and exercise dose, harmonize motor and non-motor outcome measurement, expand long-term and real-world follow-up, and evaluate mechanism- and subgroup-specific responses using rigorous clinical designs.
BackgroundDynamic cerebral autoregulation (dCA) impairment during surgery has been associated with adverse neurologic outcomes. Whether the burden of impaired dCA is related to the postoperative peripheral inflammatory response, and whether this association varies with age, remains uncertain.ObjectiveTo examine whether age modifies the association between intraoperative dCA impairment proportion and the neutrophil-to-lymphocyte ratio on postoperative day 3 (NLR3).MethodsThis single-center exploratory observational study included 57 adults undergoing elective major abdominal surgery. dCA impairment proportion was calculated as cumulative impaired dCA duration divided by valid dCA monitoring duration; impaired dCA was defined as a cerebral oximetry index (COx) ≥ 0.3 in at least one hemisphere. NLR3 was modeled using a Gamma generalized linear model with a log link. The model included continuous age, dCA impairment proportion, their interaction, baseline neutrophil-to-lymphocyte ratio (NLR0), operation duration, and sex. Robust variance estimation, bootstrap resampling, leave-one-out analysis, and alternative outcome and exposure definitions were used to assess model stability.ResultsThe age × dCA impairment proportion interaction was positive (Exp(B) = 1.193 per 10-year × 10-percentage-point increment; model-based 95% confidence interval [CI], 1.051–1.354; P = 0.006). The point estimate was unchanged with heteroskedasticity-consistent type 3 (HC3) robust standard errors, although the CI widened (95% CI, 0.975–1.459; P = 0.086). The 2,000-replicate bootstrap percentile interval for the interaction coefficient was 0.051–0.370. A log-transformed NLR3 sensitivity model yielded a similar interaction (HC3 P = 0.040), whereas no interaction was observed when cumulative impaired dCA duration was used (HC3 P = 0.915). The age-conditional slopes were imprecise. Longer operation duration was associated with higher NLR3 (Exp(B) = 1.214 per hour; 95% CI, 1.041–1.414; P = 0.013).ConclusionIn this cohort, the modeled association between dCA impairment proportion and NLR3 became more positive with increasing age. The consistency of the interaction depended on the method used to estimate uncertainty and on whether dCA impairment was expressed as a proportion or as cumulative impaired dCA duration. These findings identify an age-related pattern that merits prospective validation using standardized dCA monitoring and serial inflammatory measurements.
Successful cognitive aging (SCA) describes the preservation of cognitive abilities into advanced age, but its neural basis remains incompletely understood. Metabolic and pathological evidence implicates the posterior cingulate cortex (PCC) as a key region supporting cognitive resilience. However, functionally distinct PCC subregions have rarely been examined using complementary structural, microstructural, and functional imaging measures. In this cross-sectional secondary analysis of publicly available Human Connectome Project in Aging data, we identified 29 adults aged at least 80 years who met successful cognitive aging criteria based on episodic memory and executive function. We selected 29 adults with normal aging (NA) group and 29 middle-aged adults (MA) group matched for sex and education, yielding 87 participants. We combined structural MRI, neurite orientation dispersion and density imaging, and resting-state functional MRI to assess multimodal features across three PCC subregions. These features included cortical thickness, Neurite Density Index (NDI), Orientation Dispersion Index (ODI), Free Water Fraction (FWF), and cortex-wide functional connectivity. Both older groups showed lower cortical thickness in the dorsal and ventral PCC than the MA group. Cortical thickness, NDI, and ODI did not differ significantly between successful and normal aging. FWF was numerically lower in the left ventral PCC in SCA group, but this exploratory observation did not reach significance (Tukey-adjusted P = 0.059). Compared with the NA group, the SCA group showed significantly weaker connectivity between all PCC subregions and widespread prefrontal cortices (adjusted P < 0.05). In the pooled older-adult sample, weaker left ventral PCC–medial prefrontal connectivity correlated with better episodic memory (r = −0.430, FDR-adjusted P = 0.026), although neither within-group association was significant. These findings suggest that SCA was associated with lower PCC–prefrontal functional connectivity, but not with detectable preservation of PCC cortical thickness. The numerical FWF difference in the left ventral PCC remains exploratory and requires independent replication. These subregion-specific patterns provide a potential framework for understanding heterogeneous cognitive-aging trajectories, but require confirmation in larger longitudinal cohorts.
Age-related hearing loss (ARHL) is the most common sensory disorder in older adults. Current hearing interventions, including hearing aids and cochlear implants, face limitations in accessibility and adherence. Therefore, efforts have been devoted to elucidating the molecular mechanisms underlying cochlear aging and identifying effective therapeutic targets for ARHL. This review summarizes several molecular mechanisms implicated in cochlear aging and ARHL, including autophagy dysregulation, oxidative stress, stereocilia degeneration, and dysregulation of mitochondrial dynamics. We further discuss recent advances in potential therapeutic targets and intervention strategies associated with these pathways, and provide theoretical support for targeted interventions for ARHL.
ObjectiveClinical and epidemiological evidence suggests a link between gut microbiota and ischemic stroke severity as well as outcomes, yet inconsistent findings and unclear mechanisms underscore the need for a systematic synthesis.MethodsWe systematically reviewed and meta-analyzed observational studies linking gut microbiota to ischemic stroke, following PRISMA guidelines. The search covered PubMed, Embase, and the Cochrane Library, with animal studies and in vitro studies excluded. Two reviewers independently screened the literature, extracted data, and assessed study quality via the Newcastle–Ottawa Scale. We conducted random-effects meta-analyses using RevMan 5.3. Heterogeneity was quantified with the I2 statistic, and publication bias was assessed. Subgroup analyses were conducted to examine influential factors.ResultsFrom 17,281 initially identified records, 59 studies involving 7,463 patients were included in the final analysis. Although α-diversity measures—including Shannon, Chao1, ACE, Simpson index, and observed species richness—did not differ significantly between ischemic stroke patients and controls (all p > 0.05), subgroup analyses indicated that observed species richness (95% CI [−0.80, −0.13], p = 0.006) was notably altered in patients with cognitive impairment, and the Chao1 index (95% CI [0.01, 0.37], p = 0.04) was significantly changed in those with mood disorders. Microbial composition analysis revealed no significant differences at the phylum level. However, at the family level, stroke patients exhibited a higher abundance of Enterobacteriaceae and lower levels of Lachnospiraceae and Prevotellaceae. At the genus level, these patients exhibited higher levels of Pseudomonas and Streptococcus, along with reduced abundances of Akkermansia, Bacteroides, Coprococcus, and Roseburia.ConclusionIschemic stroke is characterized by taxonomic gut dysbiosis, whereas a decrease in α-diversity is observed only in patients who also develop cognitive impairment and mood disorders after stroke. Future multi-omics and large cohort studies should establish causality between gut microbiota and ischemic stroke, identifying therapeutic targets.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD42024506656, Identifier: CRD42024506656.
Parkinson’s disease (PD) is characterized by progressive α-synuclein aggregation, yet the molecular mechanisms underlying this process remain incompletely understood. Transcriptomic analyses may provide important insights into the RNA-mediated regulation of PD pathogenesis, but studies of affected brain tissue are limited by the inaccessibility of living brain tissue and post-mortem RNA degradation. The submandibular gland (SMG), which exhibits α-synuclein pathology comparable to that of the substantia nigra, represents a clinically accessible peripheral tissue for investigating disease-associated transcriptomic alterations. However, ultrasound-guided core needle biopsy yields only a limited amount of tissue, making comprehensive RNA sequencing technically challenging. Here, we present and validate a workflow for paired total RNA and small RNA sequencing from low-input SMG biopsy specimens obtained from patients with de novo PD and age-matched, neurologically unaffected surgical controls. Ultrasound-guided core needle biopsy yielded specimens measuring approximately 1.2 × 7–10 mm. To enable direct tissue-to-blood comparisons, fasting peripheral blood samples were collected from the same participants on the morning of biopsy. Following immediate tissue stabilization, RNA extraction, library preparation, and next-generation sequencing, workflow performance was evaluated by assessing RNA integrity, library quality, sequencing metrics, mapping performance, and reproducibility. Despite the limited tissue input, the protocol consistently generated high-quality RNA suitable for both total RNA sequencing and small RNA sequencing. The validated workflow produced robust sequencing libraries with high reproducibility and enabled comprehensive profiling of protein-coding transcripts together with multiple classes of small non-coding RNAs, including miRNAs, piRNAs, snoRNAs, snRNAs, and tRNA-derived RNAs. This validated workflow provides a practical and reproducible approach for comprehensive transcriptomic profiling of minimally invasive SMG biopsy specimens and matched fasting peripheral blood, and may facilitate future studies of disease mechanisms, biomarker discovery, and translational applications in Parkinson’s disease.
