Brain Perfusion in Corticobasal Syndrome with Progressive Aphasia

Large-scale activation likelihood estimation meta-analysis of parkinsonian disorders

Parkinsonism is a feature of several neurodegenerative disorders, including Parkinson's disease, progressive supranuclear palsy, corticobasal syndrome and multiple system atrophy. Neuroimaging studies have yielded insights into parkinsonian disorders; however, due to variability in results, the brain regions consistently implicated in these disorders remain to be characterized. The aim of this meta-analysis was to identify consistent brain abnormalities in individual parkinsonian disorders (Parkinson's disease, progressive supranuclear palsy, corticobasal syndrome and multiple system atrophy) and to investigate any shared abnormalities across disorders. A total of 44 591 studies were systematically screened following searches of two databases. A series of whole-brain activation likelihood estimation meta-analyses were performed on 132 neuroimaging studies (69 Parkinson's disease; 23 progressive supranuclear palsy; 17 corticobasal syndrome; and 23 multiple system atrophy) utilizing anatomical MRI, perfusion or metabolism PET and single-photon emission computed tomography. Meta-analyses were performed in each parkinsonian disorder within each imaging modality, as well as across all included disorders. Results in progressive supranuclear palsy and multiple system atrophy aligned with current imaging markers for diagnosis, encompassing the midbrain, and brainstem and putamen, respectively. PET imaging studies of patients with Parkinson's disease most consistently reported abnormality of the middle temporal gyrus. No significant clusters were identified in corticobasal syndrome. When examining abnormalities shared across all four disorders, the caudate was consistently reported in MRI studies, whilst the thalamus, inferior frontal gyrus and middle temporal gyri were commonly implicated by PET. To our knowledge, this is the largest meta-analysis of neuroimaging studies in parkinsonian disorders and the first to characterize brain regions implicated across parkinsonian disorders.

The Discourse Profile in Corticobasal Syndrome: A Comprehensive Clinical and Biomarker Approach

The aim of this study was to characterize the oral discourse of CBS patients and to verify whether measures obtained during a semi-spontaneous speech production could differentiate CBS patients from controls. A second goal was to compare the performance of patients with CBS probably due to Alzheimer's disease (CBS-AD) pathology and CBS not related to AD (CBS-non-AD) in the same measures, based on the brain metabolic status (FDG-PET) and in the presence of amyloid deposition (amyloid-PET). Results showed that CBS patients were significantly different from controls in speech rate, lexical level, informativeness, and syntactic complexity. Discursive measures did not differentiate CBS-AD from CBS-non-AD. However, CBS-AD displayed more lexical-semantic impairments than controls, a profile that is frequently reported in patients with clinical AD and the logopenic variant of primary progressive aphasia (lvPPA). CBS-non-AD presented mainly with impairments related to motor speech disorders and syntactic complexity, as seen in the non-fluent variant of PPA.

Which is responsible for aphasia by subcortical lesions? Subcortical lesions or the cortical hypoperfusion?

Cerebral lesions causing aphasia involve morphological and functional changes. In this study, it was aimed to explain the connection between aphasia and subcortical lesions with SPECT. The study included 30 patients diagnosed in the first three days of stroke with a single hemorrhagic or ischemic lesion in the dominant hemisphere subcortical area. Gulhane Aphasia Test and SPECT were performed. Aphasia was detected in 19 cases (63.3%). The relationship between aphasia and perfusion dysfunction in cortical and subcortical regions of the brain was evaluated, aphasia was found to be present in 15 (71.4%) of the 21 patients with cortical hypoperfusion in the dominant hemisphere and 4 (44.4%) of the 9 patients without cortical hypoperfusion; the difference was not statistically significant (p = 0.16). In the ischemia group, aphasia was present in 11 (78.5%) of the 14 cases with cortical hypoperfusion in the dominant hemisphere. Aphasia wasn't detected in any of the 5 cases that did not have cortical hypoperfusion, the difference was statistically significant (p = 0.005). When cerebral regions were evaluated separately, significant difference was reported in the aphasia seen with frontal, anterior parietal, and occipital hypoperfusion compared to cases with normal perfusion in these areas, with p = 0.003, p = 0.021, and p = 0.004, respectively. This study showed that aphasia to be more common in cases with cortical hypoperfusion in the dominant hemisphere than in cases without hypoperfusion. Our results provide evidence that direct effect of the lesion in the basal ganglia on the development of aphasia is doubtful.

The Significance of Vascular Pathogenesis in the Examination of Corticobasal Syndrome

Corticobasal syndrome (CBS) is a clinical entity, classified as an atypical Parkinsonism, characterized by both motor and higher cortical dysfunctions. The clinical manifestation of CBS is associated with several pathologies, among which corticobasal degeneration (CBD) is the most common. The aim of our study was to elaborate on the possible vascular pathogenesis of CBS and consider types of vascular lesions in these cases. Several cases of vascular CBS are described in the literature. The majority of presented patients were affected by internal carotid artery (ICA) stenosis and ischemic strokes; few cases were associated with vascular malformations or autoimmune diseases. Vascular CBS is preceded by an abrupt onset. The clinical manifestation does not significantly differ with non-vascular CBS. Patients with vascular CBS are usually elderly; often with coexistent hypertension, dyslipidemia and diabetes mellitus. Inferring from our observations, cerebral hypoperfusion can play a significant role in neuropathological changes in neurodegenerative diseases. To the best of our knowledge paper is the first comprehensive review of vascular CBS and we are positive that our observations show that further research concerning the vascular pathogenesis of tauopathy atypical Parkinsonism is required.

Language in corticobasal syndrome: a systematic review

Language is commonly impacted in corticobasal syndrome (CBS). However, the profile and type of language assessment in CBS are poorly studied.

Is brain perfusion a differentiating feature in the comparison of Progressive Supranuclear Palsy Syndrome (PSPS) and Corticobasal Syndrome (CBS)?

The aim of this work is to present whether SPECT ^99mTc-HMPAO can be a method of examination to possibly differentiate the syndromes. 21 patients with PSP syndrome and 14 patients with corticobasal syndrome (CBS) were examined using SPECT ^99mTc-HMPAO. Perfusion single photon emission computed tomography (SPECT) as a method of examination of progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) has not been extensively analyzed in contemporary literature. Recent criteria of PSP and CBS do not describe this method of examination as primary or additional. Extended analysis was done in the context of regions of interest affected by significant average hypoperfusion (>2 standard deviations). Differences between the syndromes were subsequently evaluated using the U-Mann-Whitney test. Lack of significant differences (p < 0.05) were observed in 92 out of 94 regions of interest. However, certain asymmetries were observed in a minority of regions in both of the syndromes. Additionally, the authors of the study verified possible differences of asymmetry of perfusion of both of the syndromes. The overlapping of clinical manifestations and locations of hypoperfusion leads to a question of whether the syndromes should be interpreted as separate entities or variants of the same disease.

Corticobasal syndrome: neuroimaging and neurophysiological advances

Corticobasal degeneration (CBD) is a neurodegenerative condition characterized by 4R tau protein deposition in several brain regions that clinically manifests itself as a heterogeneous atypical parkinsonism typically expressed in adulthood. The prototypical clinical phenotype of CBD is corticobasal syndrome (CBS). Important insights into the pathophysiological mechanisms underlying motor and higher cortical symptoms in CBS have been gained by using advanced neuroimaging and neurophysiological techniques. Structural and functional neuroimaging studies often show asymmetric cortical and subcortical abnormalities, mainly involving perirolandic and parietal regions and basal ganglia structures. Neurophysiological investigations including electroencephalography and somatosensory evoked potentials provide useful information on the origin of myoclonus and on cortical sensory loss. Transcranial magnetic stimulation demonstrates heterogeneous and asymmetric changes in the excitability and plasticity of primary motor cortex and abnormal hemispheric connectivity. Neuroimaging and neurophysiological abnormalities in multiple brain areas reflect asymmetric neurodegeneration, leading to asymmetric motor and higher cortical symptoms in CBS.

Neuropsychiatric disturbances in atypical parkinsonian disorders

Multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) are the most common atypical parkinsonisms. These disorders are characterized by varying combinations of autonomic, cerebellar and pyramidal system, and cognitive dysfunctions. In this paper, we reviewed the evidence available on the presence and type of neuropsychiatric disturbances in MSA, PSP, and CBD. A MedLine, Excerpta Medica, PsycLit, PsycInfo, and Index Medicus search was performed to identify all articles published on this topic between 1965 and 2018. Neuropsychiatric disturbances including depression, anxiety, agitation, and behavioral abnormalities have been frequently described in these disorders, with depression as the most frequent disturbance. MSA patients show a higher frequency of depressive disorders when compared to healthy controls. An increased frequency of anxiety disorders has also been reported in some patients, and no studies have investigated apathy. PSP patients may have depression, apathy, disinhibition, and to a lesser extent, anxiety and agitation. In CBD, neuropsychiatric disorders are similar to those present in PSP. Hallucinations and delusions are rarely reported in these disorders. Neuropsychiatric symptoms in MSA, PSP, and CBD do not appear to be related to the severity of motor dysfunction and are one of the main factors that determine a low quality of life. The results suggest that neuropsychiatric disturbances should always be assessed in patients with atypical parkinsonisms.