Relationship of white and gray matter abnormalities to clinical and genetic features in myotonic dystrophy type 1

AbstractBackgroundMyotonic dystrophy type 1 (DM1) represents a multisystemic disorder in which diffuse brain white and gray matter alterations related to clinical and genetic features have been described. We aimed to evaluate in the brain of adult patients with DM1 (i) white and gray matter differences, including cortical-subcortical gray matter volume and cortical thickness and (ii) their correlation with clinical disability, global neuropsychological performance and triplet expansion.MethodsWe included 24 adult genetically-confirmed DM1 patients (14 males; age: 38.5±11.8years) and 25 age- and sex-matched healthy controls (14 males; age: 38.5±11.3years) who underwent an identical brain MR protocol including high-resolution 3D T1-weighted, axial T2 FLAIR and DTI sequences. All patients underwent an extensive clinical and neuropsychological evaluation. Voxel-wise analyses of white matter, performed by using Tract Based Spatial Statistics, and of gray matter, with Voxel-based Morphometry and Cortical Thickness, were carried out in order to test for differences between patients with DM1 and healthy controls (p<0.05, corrected). The correlation between MRI measures and clinical-genetic features was also assessed.ResultsPatients with DM1 showed widespread abnormalities of all DTI parameters in the white matter, which were associated with reduced gray matter volume in all brain lobes and thinning in parieto-temporo-occipital cortices, albeit with less extensive cortical alterations when congenital cases were removed from the analyses. White matter alterations correlated with clinical disability, global cognitive performance and triplet expansions.ConclusionIn patients with DM1, the combined smaller overall gray matter volume and white matter alterations seem to be the main morpho-structural substrates of CNS involvement in this condition. The correlation of white matter differences with both clinical and genetic findings lends support to this notion

The Tree-Drawing Test (Koch’s Baum Test): A Useful Aid to Diagnose Cognitive Impairment

Objective. To study the Tree-Drawing Test in a group of demented patients and compare it with a group of mild cognitively impaired patients (MCI) and controls. Methods. Consecutive outpatients were classified as affected by dementia (Alzheimer’s disease (AD), frontotemporal dementia (FTD), and vascular dementia (VD)) or by MCI. Patients and controls underwent the Tree-Drawing Test and MMSE. Results. 118 AD, 19 FTD, 46 VD, and 132 MCI patients and 90 controls were enrolled. AD patients draw trees globally smaller than other patients and controls. FTD patients draw trees with a wider space occupation than AD and MCI patients but smaller than controls as well as VD patients. Trees drawn by MCI patients are intermediate in size between AD patients and controls. The trunk-to-crown ratio of trees drawn by cognitive impaired patients is greater than controls while the tree size-relative-to-page space index is significantly smaller. The tree size-relative-to-page space index of trees drawn by AD patients is smaller than that of the other cognitively impaired patients. Tree height and the trunk-to-crown ratio are independent predictors of cognitive impairment. Conclusions. Trees drawn by cognitively impaired patients are different from those drawn by healthy subjects with a progressive differentiation from mild to more relevant degrees of cognitive impairment

Effects on cognition of 20-day anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex in patients affected by mild cognitive impairment: a case-control study

Mild cognitive impairment (MCI) is a common disorder affecting as much as 15% of the elderly population. Transcranial direct current stimulation (tDCS) is a non-invasive technique of neuromodulation that has proven to influence performance in different cognitive domains

Cognitive and sleep features of multiple system atrophy: review and prospective study

The profile and degree of cognitive impairment in Multiple System Atrophy (MSA) and the impact of sleep disorders, REM sleep behavior disorder (RBD) in particular, in parkinsonism-related cognitive deficits are currently being debated

The First Historically Reported Italian Family with FTD/ALS Teaches a Lesson on C9orf72 RE: Clinical Heterogeneity and Oligogenic Inheritance

Background: In 1969, Dazzi and Finizio reported the second observation of frontotemporal dementia (FTD) - amyotrophic lateral sclerosis (ALS) association in a large Italian kindred affected by an autosomal dominant form of ALS with high penetrance, frequent bulbar onset, and frequent cognitive decline. Objective:To expand the original characterization of this family and report the link with the C9orf72 repeat expansion (RE).Methods: We followed or reviewed the medical records of thirteen patients belonging to the original family and performed genetic analyses in four individuals. Results: Eight patients presented with ALS, four with FTD, and one with schizophrenia. The C9orf72RE was found in three patients but not in the healthy survivor. Additionally, we found a novel possible pathogenic variant in the ITM2B gene in one patient with a complex phenotype, associating movement disorders, psychiatric and cognitive features, deafness, and optic atrophy. The neuropathological examination of this patient did not show the classical features of ITM2B mutation related dementias suggesting that the putative pathogenic mechanism does not involve cellular mislocalization of the protein or the formation of amyloid plaques. Conclusion: We showed that the original Italian pedigree described with FTD/ALS carries the C9orf72 RE. Moreover, the finding of an additional mutation in another dementia causing gene in a patient with a more complex phenotype suggests a possible role of genetic modifiers in the disease.Together with other reports showing the coexistence of mutations in multiple ALS/FTD causative genes in the same family, our study supports an oligogenic etiology of ALS/FTD

Human figure drawing distinguishes Alzheimer’s patients: a cognitive screening test study

To study human figure drawing in a group of Alzheimer's disease (AD) patients and compare it with a group of patients with mild cognitive impairment (MCI) and controls. We evaluated consecutive outpatients over a one-year period. Patients were classified as affected by AD or by MCI. All patients and controls underwent a simplified version of the human-figure drawing test and MMSE. A qualitative and quantitative analysis of all human figures was obtained. 112 AD, 100 MCI patients and 104 controls were enrolled. AD patients drew human figures poor in details and globally smaller than MCI patients and controls. Human figures drawn by MCI patients are intermediate in body height between those of the AD patients and the healthy subjects. The head-to-body ratio of human figures drawn by AD patients is greater than controls and MCI patients, while the human figure size-relative-to-page space index is significantly smaller. Body height is an independent predictor of cognitive impairment correlating with its severity and with the number of the figure's details. Human figures drawn by AD patients are different from those drawn by healthy subjects and MCI patients. Human figure drawing test is a useful tool for orienting cognitive impairment's diagnosis

Cerebrospinal fluid biomarkers in patients with frontotemporal dementia spectrum: A single-center study

Cerebrospinal fluid (CSF) neurofilament light chain protein (NfL) and Alzheimer's disease (AD) core biomarker levels have been evaluated in cohorts of patients with frontotemporal dementia spectrum (FTD), but the distribution of values across the different clinical syndromes and underlying proteinopathies, and the relative diagnostic accuracy appear discordant among studies. We measured CSF NfL, total (t)-tau, phosphorylated (p)-tau, and amyloid-\u3b2 (A\u3b2) 42 in healthy controls (n = 38) and subjects with a clinical, genetic, CSF biomarker-based, and/or neuropathological diagnosis of FTD (n = 141) or AD (n = 60). Sub-analyses were conducted in a proportion of subjects with definite and/or probable frontotemporal lobar degeneration with tau (FTLD-TAU) (n = 42) or TDP43 pathology (FTLD-TDP) (n = 36). Both FTD and AD groups showed significantly increased CSF NfL levels in comparison to controls (p < 0.001). CSF NfL levels were significantly higher in FTD patients than in AD (p < 0.001), reaching the highest values in amyotrophic lateral sclerosis associated with FTD. Patients with probable and definite FTLD-TDP had significantly higher NfL levels (p < 0.001) and lower p-tau/t-tau values (p < 0.001) in comparison with probable and definite FTLD-TAU cases. NfL showed good diagnostic accuracy in the distinction between FTD and controls (AUC 0.862\ub10.027) and yielded an accuracy (AUC 0.861\ub10.045) comparable to that of the p-tau/t-tau ratio (AUC 0.814\ub10.050), with 80.0% sensitivity and 81.0% specificity, in the discrimination between probable/definite FTLD-TAU and FTLD-TDP. Our data further validate CSF NfL as a surrogate biomarker of neurodegeneration and disease severity in patients with FTD spectrum. Moreover, they demonstrate a good diagnostic value for NfL and p-tau/t-tau ratio in the discrimination between FTLD-TAU and FTLD-TDP

Mitochondrial dysfunction in myotonic dystrophy type 1

The pathophysiological mechanism linking the nucleotide expansion in the DMPK gene to the clinical manifestations of myotonic dystrophy type 1 (DM1) is still unclear. In vitro studies demonstrate DMPK involvement in the redox homeostasis of cells and the mitochondrial dysfunction in DM1, but in vivo investigations of oxidative metabolism in skeletal muscle have provided ambiguous results and have never been performed in the brain. Twenty-five DM1 patients (14M, 39\u2009\ub1\u200911years) underwent brain proton MR spectroscopy (1H-MRS), and sixteen cases (9M, 40 \ub1 13 years old) also calf muscle phosphorus MRS (31P-MRS). Findings were compared to those of sex- and age-matched controls. Eight DM1 patients showed pathological increase of brain lactate and, compared to those without, had larger lateral ventricles (p\u2009<\u20090.01), smaller gray matter volumes (p\u2009<\u20090.05) and higher white matter lesion load (p\u2009<\u20090.05). A reduction of phosphocreatine/inorganic phosphate (p\u2009<\u20090.001) at rest and, at first minute of exercise, a lower [phosphocreatine] (p\u2009=\u20090.003) and greater [ADP] (p\u2009=\u20090.004) were found in DM1 patients compared to controls. The post-exercise indices of muscle oxidative metabolism were all impaired in DM1, including the increase of time constant of phosphocreatine resynthesis (TC PCr, p\u2009=\u20090.038) and the reduction of the maximum rate of mitochondrial ATP synthesis (p\u2009=\u20090.033). TC PCr values correlated with the myotonic area score (\u3c1\u2009=\u20090.74, p\u2009=\u20090.01) indicating higher impairment of muscle oxidative metabolism in clinically more affected patients. Our findings provide clear in vivo evidence of multisystem impairment of oxidative metabolism in DM1 patients, providing a rationale for targeted treatment enhancing energy metabolism

Precuneal Thickness and Depression in Parkinson Disease

Background: Depression-related gray matter changes in Parkinson disease (PD) patients have been reported, although studies investigating cortical thickness in early-stage disease are lacking. Objective: We aimed to evaluate cortical changes related to depression in early-stage PD patients with an extensive neuropsychological evaluation. Methods: 17 PD patients and 22 healthy controls underwent a 1.5-T brain MR protocol, and voxel-wise differences in cortical thickness among patients with (n = 6) and without (n = 11) depression and controls were evaluated using FreeSurfer software. Results: Cortical thickness was increased in the precuneus bilaterally in PD patients with depression compared to the other groups (number of vertices >100; p < 0.001, uncorrected) with a direct correlation with the Beck Depression Inventory score (p < 0.001, uncorrected). Conclusion: Precuneal cortical thickening is evident in PD patients with mild-moderate depression even in the early stages of the disease. This finding may reflect the early involvement of this region in the development of PD-related depression

Multiple variants in families with amyotrophic lateral sclerosis and frontotemporal dementia related to C9orf72 repeat expansion: further observations on their oligogenic nature

The C9orf72 repeat expansion (RE) is one of the most frequent causative mutations of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, it is still unclear how the C9orf72 RE can lead to a heterogeneous phenotype. Several reports have shown the coexistence of mutations in multiple ALS/FTD causative genes in the same family, suggesting an oligogenic etiology for ALS and FTD. Our aim was to investigate this phenomenon in an Italian group of ALS/FTD pedigrees carrying the C9orf72 RE. We included 11 subjects from 11 pedigrees with ALS/FTD and the C9orf72 RE. Mutation screening of FUS, SOD1 and TARDBP genes was performed by direct sequencing. A dementia-specific custom-designed targeted next-generation sequencing panel was used for screening dementia-associated genes mutations. We found genetic variants in additional ALS or dementia-related genes in four pedigrees, including the p.V47A variant in the TYROBP gene. As a group, double mutation carriers displayed a tendency toward a younger age at onset and a higher frequency of positive familiar history and of parkinsonism. Our observation supports the hypothesis that the co-presence of mutations in different genes may be relevant for the clinical expression of ALS/FTD and of their oligogenic nature