What We Do and What We Should Do Against Malnutrition in Spinal Cord Injury: A Position Paper From Italian Spinal Cord Injury Network Rehabilitation Centers.

Spinal cord injury (SCI) is a traumatic event that significantly impacts body composition and alters energy and nutritional needs. This places patients with SCI at a high risk of malnutrition, which can hinder optimal functional recovery, prolong hospital stays, increase hospital admissions, and contribute to the development of obesity and cardiovascular and metabolic ailments in chronic patients. Consequently, there is an urgent need for clear guidance to support clinicians in managing the nutritional needs of patients with SCI at different stages of the disease, including the acute (0 - 4 months after injury), post-acute (4 - 26 months after injury), and post-discharge phases. This study utilized a cross-sectional survey to assess the strategies employed in seven spinal units across Italy to address the nutritional needs of patients with SCI during the acute, post-acute, and post-discharge phases of the condition. Eight clinicians (five physiatrists, two internists, and one urologist) and one nurse participated in the survey. Following the survey completion, the participants were invited to partake in a round table session to delve deeper into the questionnaire results to gather their opinions and gain insights into clinical practices related to the various challenges surrounding the management of malnutrition in patients with SCI. We here review the available evidence on the energy needs and nutritional requirements of patients with SCI, highlighting the clinical aspects that deserve more attention throughout the distinct phases of the disease. We additionally provide an overview of the scenario regarding the management of malnutrition in patients with SCI across various spinal units in Italy. Through this comprehensive analysis, we aimed to enhance understanding and provide valuable insights for clinicians working with patients with SCI, equipping them with the knowledge and confidence to provide nutritional support to patients with SCI efficiently. By addressing the challenges of defining nutritional needs and presenting a practical guide, we aspire to contribute to the overall management and care of individuals with SCI and the prevention of malnutrition and its associated complications, thereby improving patient outcomes.

The Upper Limb Orthosis in the Rehabilitation of Stroke Patients: The Role of 3D Printing.

Stroke represents the third cause of long-term disability in the world. About 80% of stroke patients have an impairment of bio-motor functions and over half fail to regain arm functionality, resulting in motor movement control disorder with serious loss in terms of social independence. Therefore, rehabilitation plays a key role in the reduction of patient disabilities, and 3D printing (3DP) has showed interesting improvements in related fields, thanks to the possibility to produce customized, eco-sustainable and cost-effective orthoses. This study investigated the clinical use of 3DP orthosis in rehabilitation compared to the traditional ones, focusing on the correlation between 3DP technology, therapy and outcomes. We screened 138 articles from PubMed, Scopus and Web of Science, selecting the 10 articles fulfilling the inclusion criteria, which were subsequently examined for the systematic review. The results showed that 3DP provides substantial advantages in terms of upper limb orthosis designed on the patient's needs. Moreover, seven research activities used biodegradable/recyclable materials, underlining the great potential of validated 3DP solutions in a clinical rehabilitation setting. The aim of this study was to highlight how 3DP could overcome the limitations of standard medical devices in order to support clinicians, bioengineers and innovation managers during the implementation of Healthcare 4.0.

Fecal Incontinence after Severe Brain Injury: A Barrier to Discharge after Inpatient Rehabilitation?

BACKGROUND: In this study, we aimed to investigate the incidence of fecal incontinence (FI) after severe acquired brain injuries (sABIs) and to determine whether this symptom can lead to an inability to return home after rehabilitation. METHODS: This was a retrospective observational cohort study. In total, 521 acute sABI inpatients were enrolled from the Department of Neurorehabilitation at an academic tertiary care hospital. Patients were divided into two groups, with and without FI, at the end of the rehabilitation phase. The primary and secondary endpoints were the incidence of persistent FI and any difference in the discharge destination. RESULTS: Upon admission, new-onset FI was found in 443 (85%) patients, of which 38% had traumatic sABI. Moreover, 62.7% of all patients had FI upon admission. At discharge, 53.3% (264/495) of patients still had FI. Of these, 75.4% (199/264) had a Rancho Level of Cognitive Functioning Scale (LCFS) ≥3. A statistically significant correlation between FI at discharge and the presence of frontal lesions, autonomic crises, and increased LCFS scores was noted. Among the patients discharged to their homes, the proportion with persistent FI was lower (34% vs. 53.3). CONCLUSIONS: FI was significantly persistent after sABI, even after recovery from unconsciousness, and must be considered as a consequence of, rather than an independent risk factor for, unfavorable outcomes.

Bowel dysfunctions after acquired brain injury: a scoping review.

Bowel dysfunction is a common consequence of neurological diseases and has a major impact on the dignity and quality of life of patients. Evidence on neurogenic bowel is focused on spinal cord injury and multiple sclerosis; few studies have focused on patients with acquired brain injury (ABI). Neurogenic bowel dysfunction is related to a lifelong condition derived from central neurological disease, which further increases disability and social deprivation. The manifestations of neurogenic bowel dysfunction include fecal incontinence and constipation. Almost two out of three patients with central nervous system disorder have bowel impairment. This scoping review aims to comprehend the extent and type of evidence on bowel dysfunction after ABI and present conservative treatment. For this scoping review, the PCC (population, concept, and context) framework was used: patients with ABI and bowel dysfunction; evaluation and treatment; and intensive/extensive rehabilitation path. Ten full-text articles were included in the review. Oral laxatives are the most common treatment. The Functional Independence Measure (FIM) subscale is the most common scale used to assess neurogenic bowel disease (60%), followed by the Rome II and III criteria, and the colon transit time is used to test for constipation; however, no instrumental methods have been used for incontinence. An overlapping between incontinence and constipation, SCI and ABI increase difficulties to manage NBD. The need for a consensus between the rehabilitative and gastroenterological societies on the diagnosis and medical care of NBD. Systematic review registration: Open Science Framework on August 16, 2022 https://doi.org/10.17605/OSF.IO/NEQMA.

Production of emotions conveyed by voice in Parkinson's disease: Association between variability of fundamental frequency and gray matter volumes of regions involved in emotional prosody.

OBJECTIVE: Parkinson's disease (PD) is associated with impairment in producing emotions conveyed by voice which could depend on motor limitations of the vocal apparatus and/or alterations in emotional processing. This study explores the relationship between the standard deviation of fundamental frequency (F0SD) of emotional speech and the volume of specific gray matter regions. METHOD: Fifteen PD patients and 15 healthy controls (HC) were asked to produce different emotions vocally elicited by reading short stories. For each vocal track, the F0SD was calculated as index of variability. All subjects underwent a structural magnetic resonance imaging and a voxel-based morphometry analysis. An ad hoc mask of brain regions implicated in emotional prosody was constructed to test the relationship between F0SD and the level of brain atrophy. RESULTS: PD patients showed lower F0SD values than HC in the expression of anger. Neuroimaging results showed brain atrophy in PD patients in a widespread bilateral network, including frontal areas, left cingulate cortex, parietal areas as well as occipital cortices. In the PD group, a positive correlation was observed between F0SD values of anger and volumes of the bilateral supramarginal gyrus, left thalamus, right inferior frontal gyrus, and amygdala. CONCLUSIONS: The lower F0SD values observed in PD patients in anger production are consistent with their lower ability to express anger effectively through voice compared to HC. Our data demonstrated the involvement of right-lateralized areas, such as the inferior frontal gyrus and amygdala, which are typically involved in emotional prosody. Disturbances in emotion processing might contribute to speech production deficits in PD, probably in addition to the motor impairment of the articulatory system. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Blood and cerebrospinal fluid flow oscillations measured with real-time phase-contrast MRI: breathing mode matters.

BACKGROUND: Cervical blood and cerebrospinal fluid (CSF) flow rates can be quantified with Phase-contrast (PC) MRI, which is routinely used for clinical studies. Previous MRI studies showed that venous and CSF flow alterations are linked to various pathological conditions. Since it is well known that, besides the heart beating, the thoracic pump influences the blood and CSF dynamics, we studied the effect of different respiration modes on blood and CSF flow rates using a real-time (RT)-PC prototype. METHODS: Thirty healthy volunteers were examined with a 3 T scanner. A RT-PC sequence was acquired at the first cervical level to quantify the flow rates of internal carotid arteries, internal jugular veins (IJVs) and CSF. Each RT-PC acquisition was repeated three times, while the subjects were asked to breathe in three different ways for 60 s each: freely (F), with a constant rate (PN) and with deep and constant respiration rate (PD). The average flow rates were computed, they were removed from the respective signals and integrated in the inspiratory and expiratory phases (differential volumes). Finally, the power spectral density was computed for each detrended flow rate. High- and very-high frequency peaks were identified on the spectra while their frequencies were compared to the respiratory and cardiac frequencies estimated using a thoracic belt and a pulse oximeter. The area under the spectra was computed in four 0.5 Hz-wide ranges, centered on the high-frequency peak, on very-high frequency peak and its 2nd and 3rd harmonics, and then they were normalized by the flow rate variance. The effect of breathing patterns on average flow rates, on systolic and diastolic peaks, and on the normalized power was tested. Finally, the differential volumes of inspiration were compared to those of expiration. RESULTS: The frequencies of the high- and very-high spectral peaks corresponded to the respiratory and cardiac frequencies. The average flow rate progressively decreased from F to PN to PD breathing, and the cardiac modulations were less predominant especially for the IJVs. The respiratory modulation increased with PD breathing. The average volumes displaced in the inspiratory phases were not significantly different from those of the expiratory one. CONCLUSIONS: The spectral analyses demonstrated higher respiratory modulations in PD compared to free breathing, even prevailing the cardiac modulation in the IJVs, showing an increment of the thoracic pump affecting the flow rate shape.

Cardiac and Respiratory Influences on Intracranial and Neck Venous Flow, Estimated Using Real-Time Phase-Contrast MRI.

The study of brain venous drainage has gained attention due to its hypothesized link with various neurological conditions. Intracranial and neck venous flow rate may be estimated using cardiac-gated cine phase-contrast (PC)-MRI. Although previous studies showed that breathing influences the neck's venous flow, this aspect could not be studied using the conventional segmented PC-MRI since it reconstructs a single cardiac cycle. The advent of real-time PC-MRI has overcome these limitations. Using this technique, we measured the internal jugular veins and superior sagittal sinus flow rates in a group of 16 healthy subjects (12 females, median age of 23 years). Comparing forced-breathing and free-breathing, the average flow rate decreased and the respiratory modulation increased. The flow rate decrement may be due to a vasoreactive response to deep breathing. The respiratory modulation increment is due to the thoracic pump's greater effect during forced breathing compared to free breathing. These results showed that the breathing mode influences the average blood flow and its pulsations. Since effective drainage is fundamental for brain health, rehabilitative studies might use the current setup to investigate if respiratory exercises positively affect clinical variables and venous drainage.

Mid-term MRI evaluation reveals microstructural white matter alterations in COVID-19 fully recovered subjects with anosmia presentation.

Background: Little is still known about the mid/long-term effects of coronavirus disease 2019 (COVID-19) on the brain, especially in subjects who have never been hospitalized due to the infection. In this neuroimaging exploratory study, we analyzed the medium-term effect of COVID-19 on the brain of people who recovered from COVID-19, experienced anosmia during the acute phase of the disease, and have never been hospitalized due to SARS-Co-V-2 infection. Methods: Forty-three individuals who had (COV+, n = 22) or had not (COV-, n = 21) been infected with SARS-Co-V-2 were included in the study; the two groups were age- and sex-matched and were investigated using 3T magnetic resonance imaging (MRI). Gray matter (GM) volume, white matter (WM) hyperintensity volume, WM microstrutural integrity (i.e. fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity [AD], radial diffusivity [RD]) and cerebral blood flow (CBF) differences between the two groups were tested with either analysis of covariance or voxel-wise analyses. Results were family wise error (FWE) corrected. Results: No significant differences between COV+ and COV- groups were observed in terms of GM volume, WM hyperintensity volume, and CBF. Conversely, local WM microstructural alterations were detected in COV+ when compared with COV- with tract-based spatial statistics. Specifically, COV+ showed lower FA (pFWE-peak = 0.035) and higher RD (pFWE-peak = 0.038) than COV- in several WM regions. Conclusion: COVID-19 may produce mid/long-term microstructural effect on the brain, even in case of mild-to-moderate disease not requiring hospitalization. Further investigation and additional follow-ups are warranted to assess if the alterations reported in this study totally recover over time. As brain alterations could increase the risk of cognitive decline, greater knowledge of their trajectories is crucial to aid neurorehabilitation treatments.

Real-Time Phase-Contrast MRI to Monitor Cervical Blood and Cerebrospinal Fluid Flow Beat-by-Beat Variability.

Beat-by-beat variability (BBV) rhythms are observed in both cardiovascular (CV) and intracranial (IC) compartments, yet interactions between the two are not fully understood. Real-Time Phase-Contrast (RT-PC) MRI sequence was acquired for 30 healthy volunteers at 1st cervical level on a 3T scanner. The arterial (AF), venous (VF), and cerebrospinal fluid (CSF) flow (CSFF) were computed as velocity integrals over the internal carotid artery, internal jugular vein, and CSF. AF, VF, and CSFF signals were segmented in inspiration and expiration beats, to assess the respiration influence. Systolic and diastolic BBV, and heart period series underwent autoregressive power spectral density analysis, to evaluate the low-frequency (LF, Mayer waves) and high frequency (HF, respiratory waves) components. The diastolic VF had the largest BBV. LF power was high in the diastolic AF series, poor in all CSFF series. The pulse wave analyses revealed higher mean amplitude during inspiration. Findings suggests a possible role of LF modulation of IC resistances and propagation of HF waves from VF to AF and CCSF. PC-RT-MRI could provide new insight into the interaction between CV and IC regulation and pave the way for a detailed analysis of the cerebrovascular effects of varied respiration patterns due to exercise and rehabilitation.

Plasma 24-hydroxycholesterol is associated with narrower common carotid artery and greater flow velocities in relapsing multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) studies suggest greater cardiovascular disease burden and disturbances in the cholesterol pathways. The potential impact of oxidized cholesterol molecules on MS is emerging. OBJECTIVE: To determine the relationship between multiple oxysterol molecules and atherosclerosis burden in MS patients. MATERIALS AND METHODS: A total of 99 MS patients (61 relapsing-remitting MS(RRMS) and 38 progressive MS (PMS)) patients and 38 healthy controls (HCs) underwent magnetic resonance angiography (MRA) and the cross-sectional area (CSA) of the common carotid artery (CCA) was determined at three different levels before the bifurcation (C7, C6 and C5). Additionally, an echo-color Doppler ultrasound was performed and measures of blood flow velocities were derived. Blood samples acquired at the time of the imaging examinations were analyzed and 24-, 25-, 27-hydroxycholesterol (24HC, 25HC, 27HC) and 7-ketocholesterol (7KC) were quantified in ng/mL RESULTS: In the MS patients, higher levels of 24HC were significantly associated with smaller CCA CSA measured at all three cervical levels (r=-0.201, p = 0.046; r=-0.228, p = 0.023, and r=-0.215, p = 0.032, for C7, C6 and C5, respectively). These associations were driven by the RRMS group only (r=-0.407, p = 0.002 for C7; r=-0.414, p = 0.002, for C6; and r=-0.368, p = 0.006 for C5). No associations were seen in the HCs. Despite adjusting for the significant age effect (B = 0.445, p = 0.004), higher 24HC levels were independently associated with smaller CCA CSA (B=-0.20, p = 0.045). 24HC was additionally associated with greater time-averaged and peak diastolic CCA velocities. RRMS patients treated with potent anti-inflammatory therapies had lower oxysterol levels (p = 0.019). CONCLUSION: Greater 24HC levels are associated with smaller CSA CCA and greater flow velocities in RRMS patients.

Development and Testing of SPIDER-NET: An Interactive Tool for Brain Connectogram Visualization, Sub-Network Exploration and Graph Metrics Quantification.

Brain connectomics consists in the modeling of human brain as networks, mathematically represented as numerical connectivity matrices. However, this representation may result in difficult interpretation of the data. To overcome this limitation, graphical representation by connectograms is currently used via open-source tools, which, however, lack user-friendly interfaces and options to explore specific sub-networks. In this context, we developed SPIDER-NET (Software Package Ideal for Deriving Enhanced Representations of brain NETworks), an easy-to-use, flexible, and interactive tool for connectograms generation and sub-network exploration. This study aims to present SPIDER-NET and to test its potential impact on pilot cases. As a working example, structural connectivity (SC) was investigated with SPIDER-NET in a group of 17 healthy controls (HCs) and in two subjects with stroke injury (Case 1 and Case 2, both with a focal lesion affecting part of the right frontal lobe, insular cortex and subcortical structures). 165 parcels were determined from individual structural magnetic resonance imaging data by using the Destrieux atlas, and defined as nodes. SC matrices were derived with Diffusion Tensor Imaging tractography. SC matrices of HCs were averaged to obtain a single group matrix. SC matrices were then used as input for SPIDER-NET. First, SPIDER-NET was used to derive the connectogram of the right hemisphere of Case 1 and Case 2. Then, a sub-network of interest (i.e., including gray matter regions affected by the stroke lesions) was interactively selected and the associated connectograms were derived for Case 1, Case 2 and HCs. Finally, graph-based metrics were derived for whole-brain SC matrices of Case 1, Case 2 and HCs. The software resulted effective in representing the expected (dis) connectivity pattern in the hemisphere affected by the stroke lesion in Cases 1 and 2. Furthermore, SPIDER-NET allowed to test an a priori hypothesis by interactively extracting a sub-network of interest: Case 1 showed a sub-network connectivity pattern different from Case 2, reflecting the different clinical severity. Global and local graph-based metrics derived with SPIDER-NET were different between cases with stroke injury and HCs. The tool proved to be accessible, intuitive, and interactive in brain connectivity investigation and provided both qualitative and quantitative evidence.

Automated Assessment of the Substantia Nigra Pars Compacta in Parkinson's Disease: A Diffusion Tensor Imaging Study.

The substantia nigra (SN) pars compacta (SNpc) and pars reticulata (SNpr) are differentially affected in Parkinson's disease (PD). Separating the SNpc and SNpr is challenging with standard magnetic resonance imaging (MRI). Diffusion tensor imaging (DTI) allows for the characterization of SN microstructure in a non-invasive manner. In this study, 29 PD patients and 28 healthy controls (HCs) were imaged with 1.5T MRI for DTI. Images were nonlinearly registered to standard space and SNpc and SNpr DTI parameters were measured. ANCOVA and receiver operator characteristic (ROC) analyses were performed. Clinical associations were assessed with Spearman correlations. Multiple corrections were controlled for false discovery rate. PD patients presented with significantly increased SNpc axial diffusivity (AD) (1.207 ± 0.068 versus 1.156 ± 0.045, p = 0.024), with ROC analysis yielding an under the curve of 0.736. Trends with Unified Parkinson's Disease Rating Scale (UPDRS) III scores were identified for SNpc MD (rs = 0.449), AD (rs = 0.388), and radial diffusivity (rs = 0.391) (all p < 0.1). A trend between baseline SNpr MD and H&Y change (rs = 0.563, p = 0.081) over 2.9 years of follow-up was identified (n = 14). In conclusion, SN microstructure shows robust, clinically meaningful associations in PD.

Quantitative MRI using STrategically Acquired Gradient Echo (STAGE): optimization for 1.5 T scanners and T1 relaxation map validation.

OBJECTIVES: The strategically acquired gradient echo (STAGE) protocol, developed for 3T scanners, allows one to derive quantitative maps such as T1, T2*, proton density, and quantitative susceptibility mapping in about 5 min. Our aim was to adapt the STAGE sequences for 1.5T scanners which are still commonly used in clinical practice. Furthermore, the accuracy and repeatability of the STAGE-derived T1 estimate were tested. METHODS: Flip angle (FA) optimization was performed using a theoretical simulation by maximizing signal-to-noise ratio, contrast-to-noise ratio, and T1 precision. The FA choice was further refined with the ISMRM/NIST phantom and in vivo acquisitions. The accuracy of the T1 estimate was assessed by comparing STAGE-derived T1 values with T1 maps obtained with an inversion recovery sequence. T1 accuracy was investigated for both the phantom and in vivo data. Finally, one subject was acquired 10 times once a week and a group of 27 subjects was scanned once. The T1 coefficient of variation (COV) was computed to assess scan-rescan and physiological variability, respectively. RESULTS: The FA1,2 = 7°,38° were identified as the optimal FA pair at 1.5T. The T1 estimate errors were below 3% and 5% for phantom and in vivo measurements, respectively. COV for different tissues ranged from 1.8 to 4.8% for physiological variability, and between 0.8 and 2% for scan-rescan repeatability. CONCLUSION: The optimized STAGE protocol can provide accurate and repeatable T1 mapping along with other qualitative images and quantitative maps in about 7 min on 1.5T scanners. This study provides the groundwork to assess the role of STAGE in clinical settings. KEY POINTS: • The STAGE imaging protocol was optimized for use on 1.5T field strength scanners. • A practical STAGE protocol makes it possible to derive quantitative maps (i.e., T1, T2*, PD, and QSM) in about 7 min at 1.5T. • The T1 estimate derived from the STAGE protocol showed good accuracy and repeatability.

Consistent Cerebral Blood Flow Covariance Networks across Healthy Individuals and Their Similarity with Resting State Networks and Vascular Territories.

Cerebral blood flow (CBF) represents the local blood supply to the brain, and it can be considered a proxy for neuronal activation. Independent component analysis (ICA) can be applied to CBF maps to derive patterns of spatial covariance across subjects. In the present study, we aimed to assess the consistency of the independent components derived from CBF maps (CBF-ICs) across a cohort of 92 healthy individuals. Moreover, we evaluated the spatial similarity of CBF-ICs with respect to resting state networks (RSNs) and vascular territories (VTs). The data were acquired on a 1.5 T scanner using arterial spin labeling (ASL) and resting state functional magnetic resonance imaging. Similarity was assessed considering the entire ASL dataset. Consistency was evaluated by splitting the dataset into subsamples according to three different criteria: (1) random split of age and sex-matched subjects, (2) elderly vs. young, and (3) males vs. females. After standard preprocessing, ICA was performed. Both consistency and similarity were assessed by visually comparing the CBF-ICs. Then, the degree of spatial overlap was quantified with Dice Similarity Coefficient (DSC). Frontal, left, and right occipital, cerebellar, and thalamic CBF-ICs were consistently identified among the subsamples, independently of age and sex, with fair to moderate overlap (0.2 < DSC ≤ 0.6). These regions are functional hubs, and their involvement in many neurodegenerative pathologies has been observed. As slight to moderate overlap (0.2< DSC < 0.5) was observed between CBF-ICs and some RSNs and VTs, CBF-ICs may mirror a combination of both functional and vascular brain properties.

Multimodal Evaluation of Neurovascular Functionality in Early Parkinson's Disease.

Parkinson's disease (PD) is a multisystem neurological condition affecting different neurotransmitter pathways characterized by aberrant functional connectivity (FC) and perfusion alteration. Since the FC, measuring neuronal activity, and cerebral blood flow (CBF) are closely related through the neurovascular coupling (NVC) mechanism, we aim to assess whether FC changes found in PD mirror perfusion ones. A multimodal MRI study was implemented by acquiring resting state functional MRI (rsfMRI) and arterial spin labeling (ASL) datasets on a group of 26 early PD (66.8 ± 8 years, 22 males, median [interquartile range] Hoehn and Yahr = 1.5 [1]) and 18 age- and sex-matched healthy controls (HCs). In addition, a T1-weighted MPRAGE was also acquired in the same scan session. After a standard preprocessing, resting state networks (RSNs) and CBF maps were extracted from rsfMRI and ASL dataset, respectively. Then, by means of a dual regression algorithm performed on RSNs, a cluster of FC differences between groups was obtained and used to mask CBF maps in the subsequent voxel-wise group comparison. Furthermore, a gray matter (GM) volumetric assessment was performed within the FC cluster in order to exclude tissue atrophy as a source of functional changes. Reduced FC for a PD patient with respect to HC group was found within a sensory-motor network (SMN, pFWE = 0.01) and visual networks (VNs, primary pFWE = 0.022 and lateral pFWE = 0.01). The latter was accompanied by a decreased CBF (primary pFWE = 0.037, lateral pFWE = 0.014 VNs), while no GM atrophy was detected instead. The FC alteration found in the SMN of PD might be likely due to a dopaminergic denervation of the striatal pathways causing a functional disconnection. On the other hand, the changes in connectivity depicted in VNs might be related to an altered non-dopaminergic system, since perfusion was also reduced, revealing a compromised NVC. Finally, the absence of GM volume loss might imply that functional changes may potentially anticipate neurodegeneration. In this framework, FC and CBF might be proposed as early functional biomarkers providing meaningful insights in evaluating both disease progression and therapeutic/rehabilitation treatment outcome.

Parietal Perfusion Alterations in Parkinson's Disease Patients Without Dementia.

Fronto-parietal regions are involved in cognitive processes that are commonly affected in Parkinson's disease (PD). The aims of this study were to investigate cerebral blood flow (CBF) and gray matter (GM) volume within the regions belonging to the fronto-parietal circuit in people with PD (pwPD) without dementia, and to assess their association with cognitive performance. Twenty-seven pwPD without dementia (mean [SD] age = 67.4 [8.1] years, 20 males, mean [SD] Montreal Cognitive Assessment, MoCA score = 24.2 [2.9], median [IQR] Hoehn and Yahr scale = 1.5 [1-2]) and twenty-six age- and sex-matched healthy controls (HC) were scanned with arterial spin labeling (ASL) and T1-weighted magnetic resonance imaging (MRI) sequences to investigate CBF and GM volume, respectively. The cognitive performance of the enrolled pwPD was assessed with MoCA, Trail Making Test (TMT, part A, B, B-A), phonemic fluency and semantic fluency tests. The scores were adjusted for age and education. After standard preprocessing, CBF differences between pwPD and HC were tested with a voxel-wise approach. Voxel-based morphometry was used to compare pwPD and HC in terms of GM volume. Both voxel-wise comparisons between pwPD and HC were restricted to regions of the fronto-parietal circuit. The following additional voxel-wise analyses were performed within regions showing either perfusion or GM volume alterations: (1) correlation with neuropsychological test scores; (2) subgroup comparison after median split on each neuropsychological test score. Family-wise error-corrected (FWE) p-values lower than 0.05 were considered significant. Significant hypoperfusion was identified in the left inferior parietal lobule (IPL, ppeak = 0.037) and in the bilateral superior parietal lobule (SPL, left hemisphere: ppeak = 0.037; right hemisphere: ppeak = 0.049) of pwPD when compared to HC. No significant GM atrophy was observed. Local hypoperfusion did not correlate with any neuropsychological test scores. However, significantly lower CBF was observed in the left SPL and IPL of the pwPD subgroup who performed poorer on TMT part A in comparison with the pwPD subgroup that performed better. Perfusion alterations may occur in parietal regions of pwPD without dementia, and may be associated with lower visuomotor skills. Parietal CBF may be considered as a suitable early biomarker for longitudinal studies investigating cognitive decline in PD.

Uncinate fasciculus and word selection processing in Parkinson's disease.

We explored with Diffusion Tensor Imaging (DTI) technique whether the ability to select words among competitive alternatives during word production is related to the integrity of the left uncinate fasciculus (UF) in Parkinson's disease (PD). Nineteen PD patients (10 right-sided and 9 left-sided) and 17 matched healthy controls (HC) took part in the study. Participants were asked to derive nouns from verbs (reading from to read) or to generate verbs from nouns (to build from building). Noun and verb production, in this task, differ in the number of lexical entries among which the response is selected, as the noun must be selected from a larger number of alternatives compared to the verb, and thus is more demanding of processing resources. DTI evaluation was obtained for each subject. Fractional anisotropy (FA) and mean diffusivity (MD) maps were derived from DTI and median FA and MD values were computed within the left and right UF. Then, FA and MD of the left and right UF were correlated with noun and verb production. Both the left and right UF-FA correlated with the global (noun + verb) production and noun production in the whole PD group. In right-sided PD, correlations were found with the contralateral UF-FA; in left-sided PD the correlations emerged with both the left and right UF-FA. The most difficult task, noun production, significantly correlated with the right UF-FA in left-sided PD. The left UF is involved in word selection processes, and the right UF intervenes when the selection is particularly demanding of attentional resources.