Cognitive impairment in multiple system atrophy: a position statement by the Neuropsychology Task Force of the MDS Multiple System Atrophy (MODIMSA) study group

Consensus diagnostic criteria for multiple system atrophy consider dementia as a nonsupporting feature, despite emerging evidence demonstrating that cognitive impairments are an integral part of the disease. Cognitive disturbances in multiple system atrophy occur across a wide spectrum from mild single domain deficits to impairments in multiple domains and even to frank dementia in some cases. Frontal-executive dysfunction is the most common presentation, while memory and visuospatial functions also may be impaired. Imaging and neuropathological findings support the concept that cognitive impairments in MSA originate from striatofrontal deafferentation, with additional contributions from intrinsic cortical degeneration and cerebellar pathology. Based on a comprehensive evidence-based review, the authors propose future avenues of research that ultimately may lead to diagnostic criteria for cognitive impairment and dementia associated with multiple system atrophy.

Brain structural and functional connectivity in Parkinson's disease with freezing of gait

OBJECTIVE

To use a multimodal approach to assess brain structural pathways and resting state (RS) functional connectivity abnormalities in patients with Parkinson's disease and freezing of gait (PD-FoG).

METHODS

T1-weighted, diffusion tensor (DT) MRI and RS functional MRI (fMRI) were obtained from 22 PD-FoG patients and 35 controls on a 3.0 T MR scanner. Patients underwent clinical, motor, and neuropsychological evaluations. Gray matter (GM) volumes and white matter (WM) damage were assessed using voxel based morphometry and tract-based spatial statistics, respectively. The pedunculopontine tract (PPT) was studied using tractography. RS fMRI data were analyzed using a model free approach investigating the main sensorimotor and cognitive brain networks. Multiple regression models were performed to assess the relationships between structural, functional, and clinical/cognitive variables. Analysis of GM and WM structural abnormalities was replicated in an independent sample including 28 PD-FoG patients, 25 PD patients without FoG, and 30 healthy controls who performed MRI scans on a 1.5 T scanner.

RESULTS

Compared with controls, no GM atrophy was found in PD-FoG cases. PD-FoG patients showed WM damage of the PPT, corpus callosum, corticospinal tract, cingulum, superior longitudinal fasciculus, and WM underneath the primary motor, premotor, prefrontal, orbitofrontal, and inferior parietal cortices, bilaterally. In PD-FoG, right PTT damage was associated with a greater disease severity. Analysis on the independent PD sample showed similar findings in PD-FoG patients relative to controls as well as WM damage of the genu and body of the corpus callosum and right parietal WM in PD-FoG relative to PD no-FoG patients. RS fMRI analysis showed that PD-FoG is associated with a decreased functional connectivity of the primary motor cortex and supplementary motor area bilaterally in the sensorimotor network, frontoparietal regions in the default mode network, and occipital cortex in the visual associative network.

CONCLUSIONS

This study suggests that FoG in PD can be the result of a poor structural and functional integration between motor and extramotor (cognitive) neural systems.

Genotypic and phenotypic spectrum of PANK2 mutations in patients with neurodegeneration with brain iron accumulation

OBJECTIVE

Neurodegeneration with brain iron accumulation (NBIA) is a group of disorders characterized by magnetic resonance imaging (MRI) changes in basal ganglia. Both missense and nonsense mutations have been found in such patients in a gene encoding the mitochondrial pantothenate kinase (PANK2).

METHODS

We completed a mutation screen in 72 patients with the diagnosis NBIA based on clinical findings and radiological imaging. The entire coding region of the PANK2 gene (20p12.3) was investigated for point mutations and deletions.

RESULTS

We uncovered both mutant alleles in 48 patients. Deletions accounted for 4% of mutated alleles. Patients with two loss-of-function alleles (n = 11) displayed symptoms always at an early stage of life. In the presence of missense mutations (n = 37), the age of onset correlated with residual activity of the pantothenate kinase. Progression of disease measured by loss of ambulation was variable in both groups. We did not observe a strict correlation between the eye-of-the-tiger sign and PANK2 mutations. In 24 patients, no PANK2 mutation was identified.

INTERPRETATION

Deletion screening of PANK2 should be part of the diagnostic spectrum. Factors other than enzymatic residual activity are determining the course of disease. There are strong arguments in favor of locus heterogeneity.

Dystonia in Wilson's disease

The frequency and type of dystonic movements, as well as brain abnormalities, as depicted with magnetic resonance imaging (MRI), which might correlate with dystonia, were studied in 27 consecutive patients with a neurologic form of Wilson's disease (WD) and optimized treatment. Dystonia was found in 10 patients (37%), being generalized in half of them, while two patients had segmental, two patients multifocal dystonia, and one patient bilateral foot dystonia. Dystonia was a presenting sign in four patients and developed later in the course of the disease in six patients, despite the administered therapy for WD. Putamen was the only structure significantly more frequently lesioned in dystonic (80%) in comparison to WD patients without dystonia (24%), suggesting a relation between abnormalities in this brain region and dystonic movements in WD.

Cortico-striatal-thalamic network functional connectivity in hemiparkinsonism

Cortico-striatal-thalamic network functional connectivity (FC) and its relationship with levodopa (L-dopa) were investigated in 69 patients with hemiparkinsonism (25 drug-naïve [n-PD] and 44 under stable/optimized dopaminergic treatment [t-PD]) and 27 controls. Relative to controls, n-PD patients showed an increased FC between the left and the right basal ganglia, and a decreased connectivity of the affected caudate nucleus and thalamus with the ipsilateral frontal and insular cortices. Compared with both controls and n-PD patients, t-PD patients showed a decreased FC among the striatal and thalamic regions, and an increased FC between the striatum and temporal cortex, and between the thalamus and several sensorimotor, parietal, temporal, and occipital regions. In both n-PD and t-PD, patients with more severe motor disability had an increased striatal and/or thalamic FC with temporal, parietal, occipital, and cerebellar regions. Cortico-striatal-thalamic functional abnormalities occur in patients with hemiparkinsonism, antecede the onset of the motor symptoms on the opposite body side and are modulated by L-dopa. In patients with hemiparkinsonism, L-dopa is likely to facilitate a compensation of functional abnormalities possibly through an increased thalamic FC.

Mutations in GNAL: a novel cause of craniocervical dystonia

IMPORTANCE

Mutations in the GNAL gene have recently been shown to cause primary torsion dystonia. The GNAL-encoded protein (Gαolf) is important for dopamine D1 receptor function and odorant signal transduction. We sequenced all 12 exons of GNAL in 461 patients from Germany, Serbia, and Japan, including 318 patients with dystonia (190 with cervical dystonia), 51 with hyposmia and Parkinson disease, and 92 with tardive dyskinesia or acute dystonic reactions.

OBSERVATIONS

We identified the following two novel heterozygous putative mutations in GNAL: p.Gly213Ser in a German patient and p.Ala353Thr in a Japanese patient. These variants were predicted to be pathogenic in silico, were absent in ethnically matched control individuals, and impaired Gαolf coupling to D1 receptors in a bioluminescence energy transfer (BRET) assay. Two additional variants appeared to be benign because they behaved like wild-type samples in the BRET assay (p.Ala311Thr) or were detected in ethnically matched controls (p.Thr92Ala). Both patients with likely pathogenic mutations had craniocervical dystonia with onset in the fifth decade of life. No pathogenic mutations were detected in the patients with hyposmia and Parkinson disease, tardive dyskinesias, or acute dystonic reactions.

CONCLUSIONS AND RELEVANCE

Mutations in GNAL can cause craniocervical dystonia in different ethnicities. The BRET assay may be a useful tool to support the pathogenicity of identified variants in the GNAL gene.

Progressive brain atrophy and clinical evolution in Parkinson's disease

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Cortical and subcortical atrophy is accelerated early after the onset of PD.

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Brain atrophy in PD progressed with cognitive, non-motor and mood deficits.

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Structural MRI may be useful for predicting disease progression in PD.

Clinical manifestations and evolution are very heterogeneous among individuals with Parkinson’s disease (PD). The aims of this study were to investigate the pattern of progressive brain atrophy in PD according to disease stage and to elucidate to what extent cortical thinning and subcortical atrophy are related to clinical motor and non-motor evolution. 154 patients at different PD stages were assessed over time using motor, non-motor and structural MRI evaluations for a maximum of 4 years. Cluster analysis defined clinical subtypes. Cortical thinning and subcortical atrophy were assessed at baseline in patients relative to 60 healthy controls. Longitudinal trends of brain atrophy progression were compared between PD clusters. The contribution of brain atrophy in predicting motor, non-motor, cognitive and mood deterioration was explored. Two main PD clusters were defined: mild (N = 87) and moderate-to-severe (N = 67). Two mild subtypes were further identified: mild motor-predominant (N = 43) and mild-diffuse (N = 44), with the latter group being older and having more severe non-motor and cognitive symptoms. The initial pattern of brain atrophy was more severe in patients with moderate-to-severe PD. Over time, mild-diffuse PD patients had the greatest brain atrophy accumulation in the cortex and the left hippocampus, while less distributed atrophy progression was observed in moderate-to-severe and mild motor-predominant patients. Baseline and 1-year cortical thinning was associated with long-term progression of motor, cognitive, non-motor and mood symptoms. Cortical and subcortical atrophy is accelerated early after the onset of PD and becomes prominent in later stages of disease according to the development of cognitive, non-motor and mood dysfunctions. Structural MRI may be useful for monitoring and predicting disease progression in PD.

Brain structural and functional signatures of impulsive-compulsive behaviours in Parkinson's disease

This study assessed brain structural and functional alterations in patients with Parkinson's disease and impulsive-compulsive behaviours (PD-ICB) compared with controls and PD no-ICB cases. Eighty-five PD patients (35 PD-ICB) and 50 controls were recruited. All subjects underwent three-dimensional T1-weighted, diffusion tensor (DT), and resting state functional magnetic resonance imaging (RS fMRI). We assessed cortical thickness with surface-based morphometry, subcortical volumes using FIRST, DT MRI metrics using region of interest and tractography approaches, and RS fMRI using a model free approach. Compared with controls, both PD groups showed a pattern of brain structural alterations in the basal ganglia (more evident in PD no-ICB patients), sensorimotor and associative systems. Compared with PD no-ICB, PD-ICB cases showed left precentral and superior frontal cortical thinning, and motor and extramotor white matter tract damage. Compared with controls, all patients had an increased functional connectivity within the visual network. Additionally, PD no-ICB showed increased functional connectivity of bilateral precentral and postcentral gyri within the sensorimotor network compared with controls and PD-ICB. Severity and duration of PD-ICB modulated the functional connectivity between sensorimotor, visual and cognitive networks. Relative to PD no-ICB, PD-ICB patients were characterised by a more severe involvement of frontal, meso-limbic and motor circuits. These data suggest ICB in PD as the result of a disconnection between sensorimotor, associative and cognitive networks with increasing motor impairment, psychiatric symptoms, and ICB duration. These findings may have important implications in understanding the neural substrates underlying ICB in PD.

Tracking Cortical Changes Throughout Cognitive Decline in Parkinson's Disease

BACKGROUND

The objectives of this study were to investigate progressive cortical thinning and volume loss in Parkinson's disease (PD) patients with different longitudinal patterns of cognitive decline: with stable normal cognition, with stable mild cognitive impairment, with conversion to mild cognitive impairment, and with conversion to dementia.

METHODS

We recruited 112 patients (37 Parkinson's disease with stable normal cognition, 20 Parkinson's disease with stable mild cognitive impairment, 36 Parkinson's disease with conversion to mild cognitive impairment, 19 Parkinson's disease with conversion to dementia) and 38 healthy controls. All patients underwent at least 2 visits within 4 years including clinical/cognitive assessments and structural MRI (total visits, 393). Baseline cortical thickness and gray matter volumetry were compared between groups. In PD, gray matter changes over time were investigated and compared between groups.

RESULTS

At baseline, compared with Parkinson's disease with stable normal cognition cases, Parkinson's disease with conversion to mild cognitive impairment patients showed cortical atrophy of the parietal and occipital lobes, similar to Parkinson's disease with stable mild cognitive impairment and Parkinson's disease with conversion to dementia patients. The latter groups (ie, patients with cognitive impairment from the study entry) showed additional involvement of the frontotemporal cortices. No baseline volumetric differences among groups were detected. The longitudinal analysis (group-by-time interaction) showed that, versus the other patient groups, Parkinson's disease with stable mild cognitive impairment and Parkinson's disease with conversion to dementia cases accumulated the least cortical damage, with Parkinson's disease with conversion to dementia showing unique progression of right thalamic and hippocampal volume loss; Parkinson's disease with conversion to mild cognitive impairment patients showing specific cortical thinning accumulation in the medial and superior frontal gyri, inferior temporal, precuneus, posterior cingulum, and supramarginal gyri bilaterally; and Parkinson's disease with stable normal cognition patients showing cortical thinning progression, mainly in the occipital and parietal regions bilaterally.

CONCLUSIONS

Cortical thinning progression is more prominent in the initial stages of PD cognitive decline. The involvement of frontotemporoparietal regions, the hippocampus, and the thalamus is associated with conversion to a more severe stage of cognitive impairment. In PD, gray matter alterations of critical brain regions may be an MRI signature for the identification of patients at risk of developing dementia. © 2020 International Parkinson and Movement Disorder Society.

Longitudinal brain connectivity changes and clinical evolution in Parkinson's disease

Longitudinal connectivity studies might guide our understanding of the underlying neurodegenerative processes. We report the results of a longitudinal study in patients at different stages of Parkinson's disease (PD), who performed motor and non-motor evaluations and serial resting state (RS) functional MRI (fMRI). Cluster analysis was applied to demographic and clinical data of 146 PD patients to define disease subtypes. Brain network functional alterations were assessed at baseline in PD relative to 60 healthy controls and every year for a maximum of 4 years in PD groups. Progression of brain network changes were compared between patient clusters using RS fMRI. The contribution of network changes in predicting clinical deterioration was explored. Two main PD clusters were identified: mild PD (86 patients) and moderate-to-severe PD (60 patients), with the latter group being older and having earlier onset, longer PD duration, more severe motor, non-motor and cognitive deficits. Within the mild patient cluster, two clinical subtypes were further identified: mild motor-predominant (43) and mild-diffuse (43), with the latter being older and having more frequent non-motor symptoms. Longitudinal functional connectivity changes vary across patients in different disease stages with the coexistence of hypo- and hyper-connectivity in all subtypes. RS fMRI changes were associated with motor, cognitive and non-motor evolution in PD patients. Baseline RS fMRI presaged clinical and cognitive evolution. Our network perspective was able to define trajectories of functional architecture changes according to PD stages and prognosis. RS fMRI may be an early biomarker of PD motor and non-motor progression.

A laboratory-based study on patients with Parkinson's disease and seborrheic dermatitis: the presence and density of Malassezia yeasts, their different species and enzymes production

BACKGROUND

Seborrheic dermatitis (SD) and Parkinson's disease (PD) are frequently associated conditions. Aims of this study were: to determine severity of SD, presence of different species and density of Malassezia yeasts; to assess yeast lipases and phosphatases production in vitro and to compare these results between SD patients with and without PD.

METHODS

This case-control prospective study was conducted at the Dermatology and Neurology Units, Clinical Centre of Serbia and at the National Medical Mycology Reference Laboratory, University of Belgrade Medical School, Serbia. A total of 90 patients and 70 healthy controls (HC) were investigated: 60 patients with SD (SDN) and 30 patients with SD and PD (SDP). Culture-based mycological examination was carried out on lesional skin (LS) and non-lesional skin (NLS). A yeasts density was determined by counting the Malassezia colony forming units per tape (CFU/tape). Enzymes production by isolated Malassezia was investigated.

RESULTS

The most patients with SD were male (76.7%; SDP and 63.3%; SDN) and the intensity of SD was dominantly severe or moderate (76.7%; SDP and 75%; SDN). The presence of Malasseziа was high on LS in both groups (87.3%; SDP and 86.7%; SDN) (p=0.667).The highest yeasts density (mean CFU/tape=67.8) was detected on LS in 53% of SDP group and in 21.7% of SDN group (mean CFU/tape=31.9) (p < 0.01). The presence of negative cultures was lower in SDP group (13.3%) in comparison to HC and SDN groups (37% and 31.7%, respectively). Malassezia density on NLS in SDP group (mean CFU/tape=44.3) was significantly higher in comparison to SDN and HC (p=0.018). M. globosa was the most abundant species identified amongst isolates from the SDP group (42.3%) and exhibited high production of phosphatase and lipase in vitro.

CONCLUSION

From this laboratory-based study a positive correlation between SD, PD, M. globosa incidence, high yeast density and high phosphatase and lipase activity was established. Our data lead to conclusion that local skin performance of PD patient's characterized with increased sebum excretion ratio play a role in SD by stimulation of yeasts replication and enzyme production.

Apathy and depression in Parkinson's disease: the Belgrade PD study report

Apathy and depression are among the most common psychiatric and behavioral disorders associated with Parkinson's disease (PD). The objective of this study was to examine the prevalence and demographic and clinical correlates of apathy and depression in a clinical population-based sample of patients with PD and to assess whether apathy may present as a primary behavioral disturbance independent from depression and cognitive impairment. A series of 360 PD patients underwent psychiatric investigation with the Starkstein's Apathy Scale (AS), and the 17-item Hamilton Depression Rating Scale (HDRS-17), motor scoring with Hoehn and Yahr (HY) staging, and the Unified Parkinson's Disease Rating Scale (UPDRS); and cognitive screening with the Mini-Mental State Examination (MMSE) on the same day. Apathy coexisted with depression in 133 (36.9%) of PD patients, compared with depression without apathy in 16 (4.4%), apathy without depression in 84 (23%), and neither apathy nor depression in 127 PD patients (35.2%). Apathy was associated with higher axial UPDRS impairment score, lower MMSE score, higher l-dopa dosage, and earlier HY stages, while depression was predicted by the more advanced HY stages and younger age of PD patients. These findings suggest that apathy and depression may be separable in PD, although both are common in patients with PD. Therefore these two conditions should be systematically screened and considered in the care and management of PD.

Multiparametric MRI to distinguish early onset Alzheimer's disease and behavioural variant of frontotemporal dementia

This prospective study explored whether an approach combining structural [cortical thickness and white matter (WM) microstructure] and resting state functional MRI can aid differentiation between 62 early onset Alzheimer's disease (EOAD) and 27 behavioural variant of frontotemporal dementia (bvFTD) patients. Random forest and receiver operator characteristic curve analyses assessed the ability of MRI in classifying the two clinical syndromes. All patients showed a distributed pattern of brain alterations relative to controls. Compared to bvFTD, EOAD patients showed bilateral inferior parietal cortical thinning and decreased default mode network functional connectivity. Compared to EOAD, bvFTD patients showed bilateral orbitofrontal and temporal cortical thinning, and WM damage of the corpus callosum, bilateral uncinate fasciculus, and left superior longitudinal fasciculus. Random forest analysis revealed that left inferior parietal cortical thickness (accuracy 0.78, specificity 0.76, sensitivity 0.83) and WM integrity of the right uncinate fasciculus (accuracy 0.81, specificity 0.96, sensitivity 0.43) were the best predictors of clinical diagnosis. The combination of cortical thickness and DT MRI measures was able to distinguish patients with EOAD and bvFTD with accuracy 0.82, specificity 0.76, and sensitivity 0.96. The diagnostic ability of MRI models was confirmed in a subsample of patients with biomarker-based clinical diagnosis. Multiparametric MRI is useful to identify brain alterations which are specific to EOAD and bvFTD. A severe cortical involvement is suggestive of EOAD, while a prominent WM damage is indicative of bvFTD.

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Multimodal MRI distinguishes in vivo EOAD and bvFTD patients

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EOAD and bvFTD show a distributed pattern of structural brain alterations

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A severe cortical involvement is suggestive of EOAD relative to bvFTD

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A prominent WM damage is indicative of bvFTD relative to EOAD

Visuomotor skill learning on serial reaction time task in patients with early Parkinson's disease

This study tested the role of basal ganglia in visuomotor skill learning. Thirty-nine patients early in the course of Parkinson's disease (PD) and 30 patients after operation for an aneurysm of the anterior communicating artery (ACoA) were compared with 31 matched control subjects on a Serial Reaction Time test (SRTt). The patients with PD showed impaired visuomotor skill learning across the repeating blocks, in the presence of preserved declarative knowledge of embedded sequences, in contrast to the ACoA group in whom the reverse pattern was observed. The significant correlation in patients with PD between the standard neuropsychological and motor measures and the performance observed in the skill acquisition test, in the ACoA group and control subjects was not observed. The suggestion that this learning impairment could not be attributed to a motor deficit per se was also confirmed more directly for patients with PD. Accuracy of performance after the initial learning phase on the SRTt in patients with PD was associated predominantly with visual span capacity measures. Declarative knowledge of the embedded sequence of the SRTt was correlated to general cognitive and verbal span abilities in the PD group. The impairment observed in the PD group was not the result of a general decline in cognitive functioning, mood disturbances, or the severity of the motor symptoms.

Depression predicts the pattern of cognitive impairment in early Parkinson's disease

OBJECTIVE

To estimate the pattern of cognitive impairment in early Parkinson's disease (PD) associated with depression. Also, the prediction of potentially relevant demographic/clinical factors in early PD on cognitive functioning was tested.

METHOD

The study comprised 80 consecutive early PD patients (16 with major depression (PDMD), 10 PD patients with dysthimic disorder (PDDD), and 54 nondepressed PD patients (PDND)). Thirty_seven healthy subjects matched for age, gender and education were also included in the study. The cognitive evaluation included the comprehensive classical neuropsychological battery and the Cambridge Neuropsychological Test Automated Battery (CANTAB).

RESULTS

The two different patterns of cognitive impairment in early PD patients were obtained even when the confounding influences of general cognitive abilities and motor slowness were taken in account. One pattern was common to all PD patients either they were depressed or not, and it is conceived etiologically as dysexecutive. The PDDD group presented only the quantitative increment of the common deficit observed in PD. The second pattern was present in PDMD patients, involved episodic/working memory and language deficits alongside with background executive impairment. Depression was extensively associated with the cognitive dysfunction in early PD, whereas severity of the disease, age at onset and treatment were less favorable as predictors.

CONCLUSIONS

This study provides evidence that the pattern of cognitive impairment in early PD may be predicted by depression severity. Therefore, the recognition and treatment of depressive disorder in early PD is important.

Genome-wide association study in musician's dystonia: a risk variant at the arylsulfatase G locus?

Musician's dystonia (MD) affects 1% to 2% of professional musicians and frequently terminates performance careers. It is characterized by loss of voluntary motor control when playing the instrument. Little is known about genetic risk factors, although MD or writer's dystonia (WD) occurs in relatives of 20% of MD patients. We conducted a 2-stage genome-wide association study in whites. Genotypes at 557,620 single-nucleotide polymorphisms (SNPs) passed stringent quality control for 127 patients and 984 controls. Ten SNPs revealed P < 10(-5) and entered the replication phase including 116 MD patients and 125 healthy musicians. A genome-wide significant SNP (P < 5 × 10(-8) ) was also genotyped in 208 German or Dutch WD patients, 1,969 Caucasian, Spanish, and Japanese patients with other forms of focal or segmental dystonia as well as in 2,233 ethnically matched controls. Genome-wide significance with MD was observed for an intronic variant in the arylsulfatase G (ARSG) gene (rs11655081; P = 3.95 × 10(-9) ; odds ratio [OR], 4.33; 95% confidence interval [CI], 2.66-7.05). rs11655081 was also associated with WD (P = 2.78 × 10(-2) ) but not with any other focal or segmental dystonia. The allele frequency of rs11655081 varies substantially between different populations. The population stratification in our sample was modest (λ = 1.07), but the effect size may be overestimated. Using a small but homogenous patient sample, we provide data for a possible association of ARSG with MD. The variant may also contribute to the risk of WD, a form of dystonia that is often found in relatives of MD patients.

White matter abnormalities in Parkinson's disease patients with glucocerebrosidase gene mutations

Glucocerebrosidase gene mutations represent a genetic risk factor for the development of Parkinson's disease. This study investigated brain alterations in Parkinson's disease patients carrying heterozygous glucocerebrosidase gene mutations using structural and diffusion tensor magnetic resonance imaging. Among 360 Parkinson's disease patients screened for glucocerebrosidase gene mutations, 19 heterozygous mutation carriers (5.3%) were identified. Of these, 15 patients underwent a neuropsychological evaluation and a magnetic resonance imaging scan. Sixteen age- and sex-matched healthy controls and 14 idiopathic Parkinson's disease patients without glucocerebrosidase gene mutations were also studied. Tract-based spatial statistics was used to perform a white matter voxel-wise analysis of diffusion tensor magnetic resonance imaging metrics. Mean fractional anisotropy values were obtained from white matter tracts of interest. Voxel-based morphometry was used to assess gray-matter atrophy. Cognitive deficits were found in 9 mutation carrier patients (60%). Compared with controls, Parkinson's disease patients carrying glucocerebrosidase gene mutations showed decreased fractional anisotropy in the olfactory tracts, corpus callosum, and anterior limb of the internal capsule bilaterally, as well as in the right anterior external capsule, and left cingulum, parahippocampal tract, parietal portion of the superior longitudinal fasciculus, and occipital white matter. Mutation carrier patients also had decreased fractional anisotropy of the majority of white matter tracts compared with Parkinson's disease patients with no mutations. No white matter abnormalities were found in Parkinson's disease patients without glucocerebrosidase gene mutations. No gray matter difference was found between patients and controls. In Parkinson's disease patients, verbal fluency scores correlated with white matter abnormalities. Parkinson's disease patients carrying glucocerebrosidase gene mutations experience a distributed pattern of white matter abnormalities involving the interhemispheric, frontal corticocortical, and parahippocampal tracts. White matter pathology in these patients may have an impact on the clinical manifestations of the disease, including cognitive impairment.

Cerebral small vessel disease in pseudoxanthoma elasticum: three cases

BACKGROUND

Cerebral small vessel disease is rarely described in association with pseudoxanthoma elasticum (PXE), a hereditary connective tissue disorder with skin, eye and vascular manifestations. This autosomally inherited elastic tissue disease has been attributed to mutations in the ABCC6 gene located on chromosome 16p13.1. Different stroke mechanisms are suggested in PXE patients, arterial hypertension and accelerated atherosclerosis being the leading ones.

CASE DESCRIPTIONS

Case 1: A 49-year-old man with history of mild hypertension presented with recurrent transient ischemic attacks. At the age of 42, evaluation for progressive visual loss and skin changes led to diagnosis of PXE. Brain magnetic resonance imaging (MRI) disclosed multiple lacunar infarctions and confluent periventricular white matter lesions (WML). Case 2: A 71-year-old woman with history of mild hypertension suffered right-sided stroke. Diagnosis of PXE was made at the age of 48 due to severe visual loss and skin changes. Brain MRI revealed multiple lacunar infarctions and subcortical ischemic leukoencephalopathy. Case 3: A 47-year-old woman with prominent skin changes and bilateral amblyopia developed right-sided weakness. Skin biopsy confirmed PXE. Several lacunar infarcts in deep white matter and pons were revealed on MRI.

DISCUSSION

We present three patients with clinical and histopathological features of PXE who presented with multiple lacunar strokes, two with extensive confluent WML. These cases illustrate that PXE is a rare but significant risk factor for small vessel disease and stroke in patients of all age groups. Occlusive small vessel disease and subsequent lacunar infarcts and WML represent important PXE manifestations.

Unraveling ALS due to SOD1 mutation through the combination of brain and cervical cord MRI

OBJECTIVE

To explore structural and functional changes of the brain and cervical cord in patients with amyotrophic lateral sclerosis (ALS) due to mutation in the superoxide dismutase (SOD1) gene compared with sporadic ALS.

METHODS

Twenty patients with SOD1 ALS, 11 with sporadic ALS, and 33 healthy controls underwent clinical evaluation and brain MRI. Cortical thickness analysis, diffusion tensor MRI of the corticospinal tracts (CST) and corpus callosum, and resting-state functional connectivity were performed. Patients with ALS also underwent cervical cord MRI to evaluate cord cross-sectional area and magnetization transfer ratio (MTR).

RESULTS

Patients with SOD1 ALS showed longer disease duration and slower rate of functional decline relative to those with sporadic ALS. No cortical thickness abnormalities were found in patients with ALS compared with controls. Fractional anisotropy showed that sporadic ALS patients had significant CST damage relative to both healthy controls (p = 0.001-0.02) and SOD1-related ALS (p = 0.05), although the latter showed alterations that were intermediate between controls and sporadic ALS. Functional hyperconnectivity of the motor cortex in the sensorimotor network was observed in patients with sporadic ALS relative to controls. Conversely, patients with SOD1 ALS showed lower cord cross-sectional area along the whole cervical cord relative to those with sporadic ALS (p < 0.001). No cord MTR differences were found between patient groups.

CONCLUSIONS

Patients with SOD1 ALS showed cervical cord atrophy relative to those with sporadic ALS and a relative preservation of brain motor structural and functional networks. Neurodegeneration in SOD1 ALS is likely to occur primarily in the spinal cord. An objective and accurate estimate of spinal cord damage has potential in the future assessment of preventive SOD1 ALS therapies.

Clinical outcomes of two main variants of progressive supranuclear palsy and multiple system atrophy: a prospective natural history study

Progressive supranuclear palsy (PSP) and parkinsonian subtype of multiple system atrophy (MSA-P) are, after Parkinson's disease (PD), the most common forms of neurodegenerative parkinsonism. Clinical heterogeneity of PSP includes two main variants, Richardson syndrome (PSP-RS) and PSP-parkinsonism (PSP-P). Clinical differentiation between them may be impossible at least during the first 2 years of the disease. Little is known about the differences in natural course of PSP-RS and PSP-P and, therefore, in this study we prospectively followed the clinical outcomes of consecutive, pathologically unconfirmed patients with the clinical diagnoses of PSP-RS (51 patients), PSP-P (21 patients) and MSA-P (49 patients). Estimated mean survival time was 11.2 years for PSP-P, 6.8 years for PSP-RS, and 7.9 years for MSA-P, where a 5-year survival probabilities were 90, 66 and 78 %, respectively. More disabling course of PSP-RS compared to PSP-P was also highlighted through the higher number of milestones reached in the first 3 years of the disease, as well as in the trend to reach all clinical milestones earlier. We found that PSP-P variant had a more favorable course with longer survival, not only when compared to PSP-RS, but also when compared to another form of atypical parkinsonism, MSA-P.

Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

BACKGROUND

As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited.

OBJECTIVE

The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD.

METHODS

We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed.

RESULTS

We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published.

CONCLUSIONS

Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Role of habenula and amygdala dysfunction in Parkinson disease patients with punding

Objective:

To assess whether a functional dysregulation of the habenula and amygdala, as modulators of the reward brain circuit, contributes to Parkinson disease (PD) punding.

Methods:

Structural and resting-state functional MRI were obtained from 22 patients with PD punding, 30 patients with PD without any impulsive-compulsive behavior (ICB) matched for disease stage and duration, motor impairment, and cognitive status, and 30 healthy controls. Resting-state functional connectivity of the habenula and amygdala bilaterally was assessed using a seed-based approach. Habenula and amygdala volumes and cortical thickness measures were obtained.

Results:

Compared to both healthy controls and PD cases without any ICB (PD–no ICB), PD-punding patients showed higher functional connectivity of habenula and amygdala with thalamus and striatum bilaterally, and lower connectivity between bilateral habenula and left frontal and precentral cortices. In PD-punding relative to PD–no ICB patients, a lower functional connectivity between right amygdala and hippocampus was also observed. Habenula and amygdala volumes were not different among groups. PD-punding patients showed a cortical thinning of the left superior frontal and precentral gyri and right middle temporal gyrus and isthmus cingulate compared to healthy controls, and of the right inferior frontal gyrus compared to both controls and PD–no ICB patients.

Conclusions:

A breakdown of the connectivity among the crucial nodes of the reward circuit (i.e., habenula, amygdala, basal ganglia, frontal cortex) might be a contributory factor to punding in PD. This study provides potential instruments to detect and monitor punding in patients with PD.