The AD tau core spontaneously self-assembles and recruits full-length tau to filaments

Tau accumulation is a major pathological hallmark of Alzheimer's disease (AD) and other tauopathies, but the mechanism(s) of tau aggregation remains unclear. Taking advantage of the identification of tau filament cores by cryoelectron microscopy, we demonstrate that the AD tau core possesses the intrinsic ability to spontaneously aggregate in the absence of an inducer, with antibodies generated against AD tau core filaments detecting AD tau pathology. The AD tau core also drives aggregation of full-length wild-type tau, increases seeding potential, and templates abnormal forms of tau present in brain homogenates and antemortem cerebrospinal fluid (CSF) from patients with AD in an ultrasensitive real-time quaking-induced conversion (QuIC) assay. Finally, we show that the filament cores in corticobasal degeneration (CBD) and Pick's disease (PiD) similarly assemble into filaments under physiological conditions. These results document an approach to modeling tau aggregation and have significant implications for in vivo investigation of tau transmission and biomarker development.

Deep learning reveals disease-specific signatures of white matter pathology in tauopathies

Although pathology of tauopathies is characterized by abnormal tau protein aggregation in both gray and white matter regions of the brain, neuropathological investigations have generally focused on abnormalities in the cerebral cortex because the canonical aggregates that form the diagnostic criteria for these disorders predominate there. This corticocentric focus tends to deemphasize the relevance of the more complex white matter pathologies, which remain less well characterized and understood. We took a data-driven machine-learning approach to identify novel disease-specific morphologic signatures of white matter aggregates in three tauopathies: Alzheimer disease (AD), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). We developed automated approaches using whole slide images of tau immunostained sections from 49 human autopsy brains (16 AD,13 CBD, 20 PSP) to identify cortex/white matter regions and individual tau aggregates, and compared tau-aggregate morphology across these diseases. Tau burden in the gray and white matter for individual subjects strongly correlated in a highly disease-specific fashion. We discovered previously unrecognized tau morphologies for AD, CBD and PSP that may be of importance in disease classification. Intriguingly, our models classified diseases equally well based on either white or gray matter tau staining. Our results suggest that tau pathology in white matter is informative, disease-specific, and linked to gray matter pathology. Machine learning has the potential to reveal latent information in histologic images that may represent previously unrecognized patterns of neuropathology, and additional studies of tau pathology in white matter could improve diagnostic accuracy.

SCRN1: A cerebrospinal fluid biomarker correlating with tau in Alzheimer's disease

INTRODUCTION

Secernin-1 (SCRN1) is a neuronal protein that co-localizes with neurofibrillary tangles in Alzheimer's disease (AD), but not with tau inclusions in corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), or Pick's disease.

METHODS

We measured SCRN1 concentration in cerebrospinal fluid (CSF) using a novel mass spectrometric parallel reaction monitoring method in three clinical cohorts comprising patients with neurochemically characterized AD (n = 25) and controls (n = 28), clinically diagnosed Parkinson's disease (PD; n = 38), multiple system atrophy (MSA; n = 31), PSP (n = 20), CBD (n = 8), healthy controls (n = 37), and neuropathology-confirmed AD (n = 47).

RESULTS

CSF SCRN1 was significantly increased in AD (P < 0.01, fold change = 1.4) compared to controls (receiver operating characteristic area under the curve = 0.78) but not in CBD, PSP, PD, or MSA. CSF SCRN1 positively correlated with CSF total tau (R = 0.78, P = 1.1 × 10-13 ), phosphorylated tau181 (R = 0.64, P = 3.2 × 10-8 ), and Braak stage and negatively correlated with Mini-Mental State Examination score.

DISCUSSION

CSF SCRN1 is a candidate biomarker of AD, reflecting tau pathology.

HIGHLIGHTS

We developed a parallel reaction monitoring assay to measure secernin-1 (SCRN1) in cerebrospinal fluid (CSF). CSF SCRN1 was increased in Alzheimer's disease compared to healthy controls. CSF SCRN1 remained unchanged in Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, or corticobasal degeneration compared to controls. CSF SCRN1 correlated strongly with CSF phosphorylated tau and total tau. CSF SCRN1 increased across Braak stages and negatively correlated with Mini-Mental State Examination score.

Autopsy-proven patient with corticobasal degeneration presenting with visuo-constructive disorders as initial symptoms: How advanced MRI sequences can help clinical practice

BackgroundCortico-basal degeneration (CBD) is a neurodegenerative disease typically responsible for cortico-basal syndrome (CBS) or progressive limb apraxia. Half of CBD patients, however, present atypical symptoms, making the diagnosis difficult.ObjectiveWe reported the case of a woman in her late sixties (BM208), an unusual case of autopsy-proven CBD, showing early signs of Benson's syndrome or posterior cortical atrophy. In addition, we compared cognitive performance and atrophy in different brain regions of BM208 with other neurodegenerative diseases patients to highlight clinical signs that could have guided the diagnosis earlier.MethodsWe retrospectively compared BM208 to patients with typical amnestic Alzheimer's disease (AD) (n = 18, Mini-Mental State Exam (MMSE) scores between 18 and 24), Benson's syndrome due to AD (n = 3), CBS/progressive supranuclear palsy (PSP) syndrome (n = 5), and Lewy body dementia (LBD) patients (n = 3) and a control group (n = 24). All these participants underwent an MMSE, a complete neuropsychological examination and 3DT1 MRI.ResultsAlthough BM208 was more severely cognitively impaired overall, her cognitive performance was more similar to Benson's syndrome patients' cognitive profile compared to CBS patients or any other degenerative pathology (typical AD/LBD). Consistently, although BM208 was more atrophic than all other groups, she showed cortical atrophy that matched a Benson's syndrome pattern more than typical AD or CBS. However, the analysis of subcortical atrophy revealed atrophy of the basal ganglia corresponding CBS cases. Furthermore, visual analyses on sagittal T1 images showed atrophy of the midbrain, characteristic of CBS/PSP syndrome.ConclusionsThese results highlight the additive value of fine-grained MRI subcortical quantification to diagnose non-AD rare neurodegenerative disorders.

Comparing classic-onset corticobasal syndrome to speech/language-onset corticobasal syndrome

INTRODUCTION

Patients with classic-onset corticobasal syndrome (CBS) present with asymmetric limb apraxia and parkinsonism. We have, however, observed patients who initially present with speech and/or language (SL) problems and several years later develop CBS (i.e., SL-onset CBS). We aimed to compare clinical, neuroimaging and pathological characteristics of classic-onset CBS with SL-onset CBS.

METHODS

We conducted a retrospective cohort study of 62 patients who met criteria for CBS (17 presented with classic-onset CBS and 45 had SL-onset CBS). We compared demographics, clinical characteristics, and grey and white matter volume loss with SPM12 between groups and assessed pathology and corticobasal degeneration (CBD) pathological lesion counts in patients who had died and undergone autopsy.

RESULTS

Median age at CBS diagnosis was 66.4 years in classic-onset CBS and 73.6 years in SL-onset CBS. Classic-onset CBS had higher frequencies of dystonia, myoclonus, and alien limb phenomenon, while SL-onset CBS had a higher frequency of vertical supranuclear gaze palsy. Both groups showed smaller frontoparietal volumes than controls, with SL-onset CBS having greater volume loss in the left supplementary motor area than classic-onset CBS. All three classic-onset CBS cases with autopsy (100 %) had CBD pathology while 8/21 of SL-onset CBS cases (38 %) had CBD. Pathological lesion burden (including astrocytic plaques) did not differ between classic-onset and SL-onset CBS.

CONCLUSION

Classic-onset and SL-onset CBS appear to be different syndromes, with the former being a more profuse motor syndrome. The more widespread volume loss in SL-onset CBS likely reflects longer disease course.

Hypertrophy of the inferior olivary nucleus in corticobasal degeneration: A neuropathological study

AIMS

Corticobasal degeneration (CBD) is a rare neurodegenerative disorder. The status of the inferior olivary nucleus (ION) in CBD has been inadequately investigated. In this study, we conducted a pathological investigation of the ION in CBD.

MATERIALS AND METHODS

We reviewed the data of Japanese patients with pathologically confirmed CBD who underwent consecutive autopsies between 1985 and 2020 at our institute. We retrospectively examined clinical data from medical records and clinicopathological conferences and semi-quantitatively assessed the ION, central tegmental tract, superior cerebellar peduncle, and dentate nucleus.

RESULTS

Of the 32 patients included, 14 (43.8%) had hypertrophy of the ION (HION), of whom 6 showed laterality. In the 14 HION cases, with or without laterality, except in 1 unevaluable case, atrophy/myelin pallor of the central tegmental tract was observed on the same side as the hypertrophy. Ten patients with HION, with or without laterality, had atrophy/myelin pallor of the superior cerebellar peduncle on the contralateral side to the hypertrophy.

CONCLUSION

The ION presents with hypertrophic changes in CBD. The lesion is a primary degeneration in CBD and is related to the degeneration of the Guillain-Mollaret triangle. This finding contributes to the elucidation of the specific pathological characteristics of CBD.

An autopsy case of type A FTLD-TDP with a GRN mutation presenting with the logopenic variant of primary progressive aphasia at onset and with corticobasal syndrome subsequently

A 68-year-old woman presented with difficulty finding words and writing characters. Neurological examination led to clinical diagnosis at onset of the logopenic variant of primary progressive aphasia accompanied with ideomotor apraxia, visuospatial agnosia on the right, and Gerstmann syndrome. Bradykinesia and rigidity on the right with shuffling gait developed after one year. Treatment with L-dopa had no effect. The patient was diagnosed with corticobasal syndrome (CBS). Brain magnetic resonance imaging revealed diffuse cortical atrophy dominantly on the left, especially in the temporal, parietal, and occipital lobes. Positron emission tomography did not reveal any significant accumulation of amyloid β or tau protein. She died five years later. Neuropathological examination revealed diffuse cortical atrophy with severe neuronal loss and fibrous gliosis in the cortex. Neuronal cytoplasmic inclusions, short dystrophic neurites, and, most notably, neuronal intranuclear inclusions, all immunoreactive for phosphorylated TDP-43, were observed. Western blotting revealed a full length and fragments of phosphorylated TDP-43 at 45 and 23 kDa, respectively, confirming the pathological diagnosis of type A FTLD-TDP. Whole exome sequencing revealed a pathogenic mutation in GRN (c.87dupC). FTLD-TDP should be included in the differential diagnosis of CBS.

Corticobasal degeneration with visual hallucination as an initial symptom: A case report

Although the initial symptoms of corticobasal degeneration (CBD) are varied, psychiatric symptoms are uncommon. Here, we report the autopsy findings of a patient with early CBD who presented with hallucinations. A 68-year-old man developed memory loss and visions of bears and insects. Because of slow vertical eye movement, postural instability, and levodopa-unresponsive parkinsonism, the patient initially was clinically diagnosed with progressive supranuclear palsy. He died of a urinary tract infection 11 months after the onset of the disease. Histopathological examination revealed neuronal loss and gliosis, which were severe in the substantia nigra and moderate in the globus pallidus and subthalamic nucleus. Astrocytic plaques were scattered throughout the amygdala and premotor cortex. The superficial cortical layers lacked ballooned neurons and spongiosis, and tau deposition was greater in glia than in neurons. The amygdala contained a moderate number of argyrophilic grains and pretangles. Western blot analysis showed a 37-kDa band among the low-molecular-weight tau fragments. Because the CBD pathology was mild, we attributed the patient's visual hallucinations to the marked argyrophilic grain pathology. CBD can occur with psychiatric symptoms, including visual hallucinations, and argyrophilic grain pathology may be associated with psychiatric symptoms.

Differential Synaptic Loss in β-Amyloid Positive Versus β-Amyloid Negative Corticobasal Syndrome

BACKGROUND/OBJECTIVE

The corticobasal syndrome (CBS) is a complex asymmetric movement disorder, with cognitive impairment. Although commonly associated with the primary 4-repeat-tauopathy of corticobasal degeneration, clinicopathological correlation is poor, and a significant proportion is due to Alzheimer's disease (AD). Synaptic loss is a pathological feature of many clinical and preclinical tauopathies. We therefore measured the degree of synaptic loss in patients with CBS and tested whether synaptic loss differed according to β-amyloid status.

METHODS

Twenty-five people with CBS, and 32 age-/sex-/education-matched healthy controls participated. Regional synaptic density was estimated by [11C]UCB-J non-displaceable binding potential (BPND), AD-tau pathology by [18F]AV-1451 BPND, and gray matter volume by T1-weighted magnetic resonance imaging. Participants with CBS had β-amyloid imaging with 11C-labeled Pittsburgh Compound-B ([11C]PiB) positron emission tomography. Symptom severity was assessed with the progressive supranuclear palsy-rating-scale, the cortical basal ganglia functional scale, and the revised Addenbrooke's Cognitive Examination. Regional differences in BPND and gray matter volume between groups were assessed by ANOVA.

RESULTS

Compared to controls, patients with CBS had higher [18F]AV-1451 uptake, gray matter volume loss, and reduced synaptic density. Synaptic loss was more severe and widespread in the β-amyloid negative group. Asymmetry of synaptic loss was in line with the clinically most affected side.

DISCUSSION

Distinct patterns of [11C]UCB-J and [18F]AV-1451 binding and gray matter volume loss, indicate differences in the pathogenic mechanisms of CBS according to whether it is associated with the presence of Alzheimer's disease or not. This highlights the potential for different therapeutic strategies in CBSs. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Huntingtin CAG repeats in neuropathologically confirmed tauopathies: Novel insights

Previous studies have suggested a relationship between the number of CAG triplet repeats in the HTT gene and neurodegenerative diseases not related to Huntington's disease (HD). This study seeks to investigate whether the number of CAG repeats of HTT is associated with the risk of developing certain tauopathies and its influence as a modulator of the clinical and neuropathological phenotype. Additionally, it aims to evaluate the potential of polyglutamine staining as a neuropathological screening. We genotyped the HTT gene CAG repeat number and APOE-ℰ isoforms in a cohort of patients with neuropathological diagnoses of tauopathies (n=588), including 34 corticobasal degeneration (CBD), 98 progressive supranuclear palsy (PSP) and 456 Alzheimer's disease (AD). Furthermore, we genotyped a control group of 1070 patients, of whom 44 were neuropathologic controls. We identified significant differences in the number of patients with pathological HTT expansions in the CBD group (2.7%) and PSP group (3.2%) compared to control subjects (0.2%). A significant increase in the size of the HTT CAG repeats was found in the AD compared to the control group, influenced by the presence of the Apoliprotein E (APOE)-ℰ4 isoform. Post-mortem assessments uncovered tauopathy pathology with positive polyglutamine aggregates, with a slight predominance in the neostriatum for PSP and CBD cases and somewhat greater limbic involvement in the AD case. Our results indicated a link between HTT CAG repeat expansion with other non-HD pathology, suggesting they could share common neurodegenerative pathways. These findings support that genetic or histological screening for HTT repeat expansions should be considered in tauopathies.

Corticobasal degeneration: An update

Corticobasal degeneration (CBD) is one of the primary tauopathies with a disease onset in the 5th to 7th decade. CBD is a progressive condition of unknown aetiology, which is characterised neuropathologically by neuronal loss, astrogliosis and deposition of filamentous tau inclusions, composed entirely of 4-repeat tau isoforms, in neurons and glial cells in cerebral cortical areas, basal ganglia, brainstem and cerebellar nuclei. The term CBD is now a neuropathological diagnostic one and for the canonical clinical syndrome associated with CBD neuropathological changes, the corticobasal syndrome (CBS) term is used. In addition to CBS, the clinical spectrum also includes a behavioural variant of frontotemporal dementia syndrome, speech disorders, Richardson’s syndrome and, rarely, posterior cortical syndrome. In addition to CBD, CBS can also be caused by other pathologies. A number of genetic risk factors of CBD have been identified. As specific biomarkers confirming CBD as the underlying pathology responsible for CBS or other clinical manifestations are still lacking, for a definitive diagnosis of CBD neuropathological investigation is required. Recent cryo-electron microscopic studies have proven that CBD is a distinct tauopathy associated with a unique molecular structure of the tau filaments, which firmly differentiates it from other primary tauopathies. 

Upper motor neuron-predominant motor neuron disease presenting as atypical parkinsonism: A clinicopathological study

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by upper and lower motor neuron signs. There are, however, cases where upper motor neurons (UMNs) are predominantly affected, leading to clinical presentations of UMN-dominant ALS or primary lateral sclerosis. Furthermore, cases exhibiting an UMN-predominant pattern of motor neuron disease (MND) presenting with corticobasal syndrome (CBS) have been sparsely reported. This study aims to clarify the clinicopathological features of patients with UMN-predominant MND. We reviewed 24 patients with UMN-predominant MND with TDP-43 pathology in the presence or absence of frontotemporal lobar degeneration. Additionally, we reviewed the medical records of patients with pathologically-confirmed corticobasal degeneration (CBD) who received a final clinical diagnosis of CBS (n = 10) and patients with pathologically-confirmed progressive supranuclear palsy (PSP) who received a final clinical diagnosis of PSP syndrome (n = 10). Of 24 UMN-predominant MND patients, 20 had a clinical diagnosis of an atypical parkinsonian disorder, including CBS (n = 11) and PSP syndrome (n = 8). Only two patients had antemortem diagnoses of motor neuron disease. UMN-predominant MND patients with CBS less frequently exhibited apraxia than those with CBD, and they were less likely to meet clinical criteria for possible or probable CBS. Similarly, UMN-predominant MND patients with PSP syndrome less often met clinical criteria for probable PSP than PSP patients with PSP syndrome. Our findings suggest that UMN-predominant MND can mimic atypical parkinsonism, and should be considered in the differential diagnosis of CBS and PSP syndrome, in particular when criteria are not met.

Clinical Manifestations

BACKGROUND

Corticobasal syndrome (CBS) corresponds to a clinical phenotype with heterogeneous neuropathology, including corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), Alzheimer's disease (AD), and synucleinopathies such as Lewy Body Disease (LBD), in rare cases. Previous reports of CBS-LBD describe patients with diffuse LBD, a younger age of onset and occasionally lacking core features like REM sleep Behavior Disorder (RBD).

METHOD

We present a young patient with CBS who had a rapid progression and was found to have a high burden of limbic LBD and high AD co-pathology at autopsy.

RESULT

A 58-year-old right-handed woman consulted for progressively worsening apraxia, writing, and visuospatial difficulties over the year prior to presentation. She had minimal short-term memory loss initially, did not have RBD nor visual hallucinations and remained independent in activities of daily living. She scored 20/30 on the Montreal Cognitive Assessment, with difficulties in visuospatial and executive tasks. The neurological exam showed predominant apraxia, asymmetric parkinsonism and sensory neglect, all left-sided. The brain MRI confirmed striking asymmetric atrophy affecting the right parieto-temporal lobes. Cerebrospinal fluid (CSF) demonstrated decreased Abeta 42/tau index and elevated total and phosphorylated tau. Her condition progressed quickly over the next year, and she passed away four years after diagnosis. Brain autopsy showed asymmetric moderate-severe cortical atrophy with abundant phospho-synuclein positive Lewy bodies extending to the temporal but not frontal/parietal cortices, consistent with limbic (transitional) LBD and high Alzheimer's disease co-pathology (A3, B3, C3). There was severe Lewy body pathology in the hippocampal CA2 subfield, prominent phospho-tau in the substantia nigra, severe neuron loss in the locus coeruleus, and severe gliosis in the motor cortex.

CONCLUSION

AD and LBD commonly occur together, but the frequency of AD and LBD as a cause of CBS is unknown. Here, we add to the literature of co-pathology in CBS and consider that early age and rapid progression could suggest dual pathology and potential synergistic effects. CSF testing limited to AD biomarkers will miss this dual pathology. Thus, CSF α-synuclein seeding amplification may help identify patients with dual AD-LBD pathology and assist prognostication.

Legumain/asparaginyl endopeptidase-resistant tau fibril fold produces corticobasal degeneration-specific C-terminal tau fragment

Corticobasal degeneration (CBD) is a major four-repeat tauopathy along with progressive supranuclear palsy (PSP). Although detergent-insoluble 37-40-kDa carboxyl-terminal tau fragments (CTFs) are hallmarks of CBD pathology, the process of their formation is unknown. This study monitored the formation of CBD-type fibrils that exhibit astrocytic plaques, a characteristic CBD pathology, using its biochemical properties different from those of Alzheimer's disease/PSP-type fibrils. Tau fibrils from patients with CBD were amplified in non-astrocytic cultured cells, which maintained CBD-specific biochemical properties. We found that the lysosomal protease Legumain (LGMN) was involved in the generation of CBD-specific 37-40-kDa CTFs. While LGMN cleaved tau fibrils at Asn167 and Asn368 in the brain tissues of patients with Alzheimer's disease and PSP, tau fibrils from patients with CBD were predominantly resistant to cleavage at Asn368 by LGMN, resulting in the generation of CBD-specific CTFs. LGMN preference in tau fibrils was lost upon unraveling the tau fibril fold, suggesting that the CBD-specific tau fibril fold contributes to CBD-specific CTF production. From these findings, we found a way to differentiate astrocytic plaque from tufted astrocyte using the anti-Asn368 LGMN cleavage site-specific antibody. Inoculation of tau fibrils amplified in non-astrocytic cells into the mouse brain reproduced LGMN-resistant tau fibrils and recapitulated anti-Asn368-negative astrocytic plaques, which are characteristic of CBD pathology. This study supports the existence of disease-specific tau fibrils and contribute to further understanding of the tauopathy diagnosis. Our tau propagation mouse model using cellular tau seeds may contribute to uncovering disease mechanisms and screening for potential therapeutic compounds.

Subcortical tau burden correlates with regional brain atrophy and plasma markers in four-repeat tauopathy parkinsonism

Background18F-florzolotau positron emission tomography (PET) assists in the in vivo diagnosis of progressive supranuclear palsy (PSP).ObjectiveWe aimed to investigate the relationship between 18F-florzolotau uptake and clinical severity, structural volume changes, and plasma markers in four-repeat tauopathies.MethodsA total of 80 participants were recruited: 35 with PSP (11 with PSP-Richardson syndrome and 24 with PSP non-Richardson syndrome), 9 with corticobasal syndrome (CBS), 10 with Alzheimer's disease (AD), 8 with Parkinson's disease, and 18 controls. All participants underwent 18F-florzolotau PET, brain magnetic resonance imaging (MRI), and plasma biomarker investigation (total and phosphorylated tau [pTau181], neurofilament light chain, and glial fibrillary acidic protein [GFAP]).Results18F-Florzolotau uptake was significantly higher in the subcortical regions of the pallidum, subthalamic nucleus (STN), midbrain, red nucleus, and raphe nucleus in PSP patients compared to the other groups (all p < 0.01). Subcortical tau tracer retention assisted in distinguishing PSP and CBS from controls (AUC = 0.836, p < 0.001). Tau tracer retention could differentiate PSP and CBS from AD in cortical (p < 0.001) and subcortical regions (p = 0.028). The motor severity of PSP positively correlated with tau burden in STN (p = 0.044) and substantia nigra (p = 0.035). Tau tracer uptake was associated with cortical volume changes in CBS (p = 0.031), PSP non-Richardson syndrome (p = 0.003), and AD (p = 0.044). Cortical tau retention correlated with plasma levels of GFAP (p = 0.001) and pTau181 (p = 0.036).ConclusionsSubcortical 18F-Florzolotau uptake assist the diagnosis of 4R tauopathy parkinsonism. Additionally, regional tau burden contributes to structural brain volume changes and correlates with plasma levels of GFAP and pTau181.

Pathomechanisms of neuropsychiatric disturbances in atypical parkinsonian disorders: a current view

Multiple system atrophy (MSA), corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) are the most common atypical parkinsonisms. These adult-onset and lethal neurodegenerative disorders of unknown etiology are clinically characterized by varying combinations of autonomic, levodopa-poorly responsive parkinsonsm, motor, non-motor, cerebellar syndromes, behavioral, cognitive and other neuropsychiatric disorders. Although their pathological hallmarks are different-MSA α-synucleinopathy, CBD and PSP 4-repeat (4R) tauopathies-their neuropsychiatric disturbances include anxiety, depression, agitations, attention-executive dysfunctions, less often compulsive and REM sleep behavior disorders (RBD), which may contribute to disease progression and reduced quality of life (QoL) of patients and caregivers. The present paper reviews the prevalence and type of neuropsychiatric profile in these atypical parkinsonian syndromes, their neuroimaging, and pathogenic backgrounds based on extensive literature research. MSA patients show anxiety, apathy (depression), initial RBD, attentional and executive dysfunction; PSP patients present with apathy, depression, disinhibition, and to a lesser extent, anxiety and agitation; CBD patients are featured by executive and visuospatial dysfunctions, irritability, alien limb phenomena, sleep and language disorders. Neuropsychiatric disorders in these syndromes are often similar, due to disruption of prefronto-subcortical (limbic) and striato-thalamo-cortical circuitries or default mode and attention network disorder. This supports the concept that they are brain network disorders due to complex pathogenic mechanisms related to the basic proteinopathies that are still poorly understood. Psychotic symptoms, hallucinations and delusions are rare. Neuropsychiatric changes in these disorders are often premature and anticipate motor dysfunctions; their assessment and further elucidation of their pathogenesis are warranted as a basis for early diagnosis and adequate treatment of these debilitating comorbidities.