Is the pathology of corticobasal syndrome predictable in life?

Corticobasal syndrome (CBS) has been associated with a heterogeneous spectrum of pathologies with an increasing number of reports of Alzheimer's type pathology. There is, however, no means of predicting pathology of CBS in vivo at present. We compared the clinical features of patients presenting with CBS who have either pathologic changes of classic corticobasal degeneration (CBD) or Alzheimer's disease (AD) at post‐mortem to identify predictors of the specific pathological processes in life. Twelve patients with CBS were followed prospectively; six had AD and six had classic CBD neuropathology. After review of the presenting clinical features, we identified nine potential predictor variables, compared their frequency in the two groups, and performed a discriminant function analysis. Initial episodic memory complaints and poor performance on the combined orientation‐memory subtest of the Addenbrooke's Cognitive Examination (ACE) reliably predicted AD pathology while varying combinations of early frontal‐lobe type behavioral symptoms, nonfluent language disturbance, orobuccal apraxia, and utilization behavior predicted CBD pathology ante‐mortem. CBS is frequently associated with Alzheimer's disease pathology. Early episodic memory impairment versus early behavioral symptomatology appears to best predict AD or CBD pathology in life. © 2009 Movement Disorder Society     

Alzheimer's disease and corticobasal degeneration presenting as corticobasal syndrome

The aim of this article is to compare patients with Alzheimer's disease (AD) pathology and corticobasal degeneration pathology (CBD) presenting as corticobasal syndrome (CBS). Clinicopathologic series was used. Five patients with AD and 11 patients with CBD were clinically diagnosed with CBS. Patients with AD pathology had an earlier age of onset than patients with CBD pathology (58 vs. 68 years, P = 0.004), but the two groups had similar disease duration and core features of CBS. Tremors were only present in CBD cases (73%, P = 0.026), but myoclonus was more common in AD than CBD (80 vs. 18%, P = 0.036). Neuropsychological testing showed similar degrees of memory impairment and attentional deficits. ^99mTc‐HMPAO SPECT imaging demonstrated parietal hypoperfusion in AD patients and frontotemporal hypoperfusion in CBD patients. AD patients with clinical CBS have similar characteristics to CBD patients. Functional brain imaging may have greater utility than the clinical and neuropsychological features in differentiating AD presenting as CBS from CBD. © 2009 Movement Disorder Society     

Dystonia in corticobasal degeneration: a review of the literature on 404 pathologically proven cases

Dystonia is considered one of the classical features of corticobasal degeneration and is reported in up to 83% in clinical, not pathologically confirmed, series. Here, we aimed to establish the frequency and the clinical characteristics of dystonia in CBD by reviewing the literature on 404 pathologically proven cases. Further, we aimed to identify the frequency and characteristics of dystonia in all described phenotypes with CBD pathology. Dystonia was present in only 37.5% of the 296 cases with adequate information. The majority of the cases with dystonia presented with a corticobasal syndrome, and dystonia occurred in the first 2 years from disease onset, affecting the upper limb. In cases with dystonia that presented with a "dementia" phenotype, dystonia tended to appear later in the disease course and to more affect the cervical region and the face. With regard to the distribution of the phenotypes, fifty-four percent of 374 cases presented as corticobasal syndrome, 15% as frontotemporal dementia, and 10.7% as progressive supranuclear palsy. Dystonia and myoclonus were present in about half of all cases with corticobasal syndrome, implying that these features may not be as frequent in corticobasal syndrome as are akinetic-rigid syndrome and apraxia (100% and 86.3%, respectively). Dystonia and myoclonus almost co-occurred in our analysis, suggesting a possible association. In conclusion, despite dystonia being an inclusion criterion in all sets of clinical criteria for corticobasal degeneration, this was present in only one third of the pathologically proven cases presented here. More accurate characterization of dystonia in corticobasal degeneration would be of importance for clinical diagnosis and development of treatment strategies.     

Abnormal cytoskeletal pathology peculiar to corticobasal degeneration is different from that of Alzheimer's disease or progressive supranuclear palsy

An autopsy case of clinically diagnosed “corticobasal degeneration (CBD)” was investigated. In addition to status spongiosus and neuronal achormasia around the central sulcus, cortical pyramidal neurons and thread-like structures were densely stained by Gallyas stain and tau immunohistochemistry, but apparent fibrillary structures like Alzheimer's disease neurofibrillary tangle were absent. Bodian, methenamine-Bodian, Congo red, thioflavin S, or Bielshowsky stains failed to visualize these structures. They were not stained by immunohistochemical stain with anti-ubiquitin antibody. The widespread cytoskeletal pathology, which is distinct from that in Alzheimer's disease or progressive supranuclear palsy, is suggestive of CBD.     

The diagnostic challenge of corticobasal degeneration: distinction between clinical syndrome and pathology

Corticobasal degeneration (CBD) is a neurodegenerative disease characterised by linear progression, asymmetrical and extrapyramidal symptoms such as rigor and dystonia, as well as by variable cortical symptoms including apraxia, cortical sensory deficits, the alien limb phenomenon and myoclonism of the reflexes. Pathological changes of CBD consist of characteristic taupathology in the gray and white matter. However, there are also patients with neurodegenerative diseases with a different underlying pathology that nevertheless appear clinically as CBD. For that reason, the term corticobasal syndrome (CBS) is commonly used to describe the clinical features, whereas the term CBD is reserved for the pathological entity. Moreover, patients with the typical pathology of CBD can present clinical signs consistent with a clinical diagnosis of Alzheimer's disease (AD) or progressive supranuclear palsy (PSP). We demonstrate this clinico-pathological heterogeneity by presenting two illustrative case reports. The first patient developed the typical clinical symptoms of progressive supranuclear palsy, while exhibiting pathologically CBD. The second patient showed clinical signs of CBS, although pathologically she was diagnosed with Alzheimer's disease. These exemplary cases underscore the need to distinguish carefully between the clinical syndrome of CBS and the pathologically defined entity of CBD.     

Relationship between frontotemporal dementia and corticobasal degeneration/progressive supranuclear palsy

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) were described as separate entities, but prior to that an extrapyramidal variety of Pick's disease was recognized. Subsequently a pathological overlap between these conditions and clinical overlap between frontotemporal dementia, primary progressive aphasia, corticobasal degeneration syndrome and more recently PSP was recognized. Initially only the movement disorder had been emphasized, but now the behavioral and language symptoms are considered common. The syndromes of frontotemporal dementia/Pick's disease can be produced by underlying CBD, PSP or Pick pathology as well as with neural inclusions of the motor neuron disease type. The concept of this overlap has been confirmed genetically finding a similar spectrum of pathology with different tau mutations and even with tau negative pathology, which could be a deficiency of normal tau. The overlap of CBD with PSP and both with PPA and FTD allows to consider these relatively rare conditions as part of a more commonly occurring degenerative disease than previously recognized.     

The many faces of corticobasal degeneration

Corticobasal degeneration (CBD) has characteristic neuropathological features, but is a clinically heterogeneous disorder. It can present with various clinical syndromes. The corticobasal syndrome (CBS) is the best recognized and over the course of the illness may be the most common manifestation. Dementia, progressive non-fluent aphasia, speech apraxia, progressive supranuclear palsy (PSP)-like syndrome and posterior cortical atrophy syndrome are other presentations of CBD. The CBS is not specific for the pathology of CBD. Patients presenting as CBS have CBD as the underlying pathology in about 55% of the cases, PSP pathology in 20%, Pick's disease in 7%, and non tau pathology in the remaining. CBS is a sensitive clinical phenotype for tau pathology. Patients with CBS could potentially be candidates for therapies aiming to modify tau biochemistry.     

Progressive supranuclear palsy combined with Alzheimer's disease: A clinicopathological study of two autopsy cases

We present here the clinicopathological characteristics of two autopsy‐confirmed cases comorbid of progressive supranuclear palsy (PSP) and Alzheimer's disease (AD). Histopathologically, the amount and distribution of neurofibrillary tangles (NFTs) in the basal ganglia and brainstem fulfilled the pathological criteria of PSP proposed by the National Institute of Neurological Disorders and Stroke – The Society for PSP (NINDS‐SPSP). The Braak stages of senile plaques and NFTs were stage C and stage V in Case 1, and stage C and stage IV in Case 2. These neuropathological findings confirmed that the two patients had combined PSP with AD. Our patients presented clinically with executive dysfunction prior to memory disturbance as an early symptom. Not only neurological symptoms such as gait disturbance, supranuclear ophthalmoplegia and pseudobulbar palsy, but emotional and personality changes and delirium were prominent. Therefore, symptoms of subcortical dementia of PSP were more predominant than AD‐related symptoms in the present two patients. Comorbid PSP and AD further complicates the clinical picture and makes clinical diagnosis even more difficult.     

Typical cerebral metabolic patterns in neurodegenerative brain diseases

The differential diagnosis of neurodegenerative brain diseases on clinical grounds is difficult, especially at an early disease stage. Several studies have found specific regional differences of brain metabolism applying [¹⁸F]‐fluoro‐deoxyglucose positron emission tomography (FDG‐PET), suggesting that this method can assist in early differential diagnosis of neurodegenerative brain diseases. We have studied patients who had an FDG‐PET scan on clinical grounds at an early disease stage and included those with a retrospectively confirmed diagnosis according to strictly defined clinical research criteria. Ninety‐six patients could be included of which 20 patients with Parkinson's disease (PD), 21 multiple system atrophy (MSA), 17 progressive supranuclear palsy (PSP), 10 corticobasal degeneration (CBD), 6 dementia with Lewy bodies (DLB), 15 Alzheimer's disease (AD), and 7 frontotemporal dementia (FTD). FDG PET images of each patient group were analyzed and compared to18 healthy controls using Statistical Parametric Mapping (SPM5). Disease‐specific patterns of relatively decreased metabolic activity were found in PD (contralateral parietooccipital and frontal regions), MSA (bilateral putamen and cerebellar hemispheres), PSP (prefrontal cortex and caudate nucleus, thalamus, and mesencephalon), CBD (contralateral cortical regions), DLB (occipital and parietotemporal regions), AD (parietotemporal regions), and FTD (frontotemporal regions). The integrated method addressing a spectrum of various neurodegenerative brain diseases provided means to discriminate patient groups also at early disease stages. Clinical follow‐up enabled appropriate patient inclusion. This implies that an early diagnosis in individual patients can be made by comparing each subject's metabolic findings with a complete database of specific disease related patterns. © 2010 Movement Disorder Society     

Clinical features differentiating patients with postmortem confirmed progressive supranuclear palsy and corticobasal degeneration

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are often clinically confused with each other because they share a rapid disease progression, parkinsonism that responds poorly or transiently to levodopa therapy, and associated signs (e.g., ocular abnormalities, pyramidal signs and cognitive involvement). To improve the accuracy in diagnosing these disorders, this study examined the clinical features of 51 patients pathologically diagnosed with PSP and CBD. Logistic regression analysis identified two sets of predictors (models) for CBD patients, one consisting of asymmetric parkinsonism, cognitive disturbances at onset and instability and falls at first clinic visit, and the other one of asymmetric parkinsonism, cognitive disturbances at symptom onset and speech disturbances. While PSP patients often had severe postural instability at onset, symmetric parkinsonism, vertical supranuclear gaze palsy, speech and frontal lobe-type features, CBD patients presented with lateralized motor (e.g., parkinsonism, dystonia or myoclonus) and cognitive signs (e.g., ideomotor apraxia, aphasia or alien limb). On the other hand, CBD patients presenting with an alternate phenotype characterized by early severe frontal dementia and bilateral parkinsonism were generally misdiagnosed. PSP patients without vertical supranuclear gaze palsy were misdiagnosed. Recognizing the features which differentiate these disorders and the less obvious disease presentations as well as developing an increased index of suspicion will improve the diagnostic accuracy of these disorders.

     

Pathological heterogeneity in progressive supranuclear palsy and corticobasal degeneration

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are sporadic neurodegenerative disorders of late adult life. Focal asymmetric cortical atrophy with ballooned neurons, nigral degeneration, and tau‐positive neuronal and glial lesions in both the gray and white matter, especially astrocytic plaques in the affected cerebral cortex, are characteristic features of CBD. While cortical involvement may occur in PSP, ballooned neurons are sparse and limited to the limbic system, and tufted astrocytes are abundant in the precentral gyrus and striatum. The present findings suggest that PSP and CBD are distinct pathological entities. However, there exist ‘atypical’ cases of PSP and CBD. Severe cortical involvement or asymmetric cortical atrophy can be seen in PSP. Ballooned neurons are sparse or difficult to detect in some cases of CBD, in spite of typical cortical tau pathology. Cortical symptoms are absent or only mild in ‘minimal change’ CBD. Moreover, several neurodegenerative disorders can underlie CBD. This pathological heterogeneity leads to difficulty in the clinical and pathological diagnosis of both disorders.     

An autopsied case of corticobasal degeneration presenting with frontotemporal dementia followed by myoclonus

A Japanese woman developed frontotemporal dementia (FTD)‐like symptoms of abnormal behavior, such as stereotyped behavior and disinhibition. The patient developed these symptoms at the age of 59 years, although aphasia symptoms were not apparent at early disease stages. Progressive parkinsonism was dominant on the left side, and conspicuous myoclonus was recognized in the late disease stage. MRI indicated severe, right side‐dominant frontotemporal lobe atrophy with white matter degeneration. Brainstem and cerebellar atrophy were also observed. The patient underwent gastrostomy 7 years after the onset of her symptoms and died at the age of 70 years. Neuropathological examination showed diffuse neuron loss with gliosis and tissue rarefaction in the frontotemporal lobe, particularly in the right anterior portion of the frontal lobe. Spongiform changes and ballooned neurons were also observed in the frontotemporal cortex, particularly in the superficial layer and deeper layers, respectively. Gallyas‐Braak silver staining and anti‐phosphorylated tau immunostaining indicated numerous argyrophilic and tau‐positive structures, including pretangles, astrocytic plaques, coiled bodies and neuropil threads. We speculate that the myoclonus observed in the present case was at least partly caused by or related to the spongiform change and ballooned neurons in the cerebral cortex. The clinical phenotypes of corticobasal degeneration (CBD) vary considerably, and the clinical presentation of the present patient was compatible with frontal behavioral‐spatial syndrome in the early disease stage. However, in the later disease stages, her symptoms were reflective of corticobasal syndrome. Because it is not rare for the clinical phenotype to change along with disease progression in cases of CBD, we should consider CBD in cases presenting with FTD at symptom onset.     

Chameleons and mimics: Progressive supranuclear palsy and corticobasal degeneration

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are neurodegenerative disorders that show parkinsonism as their main symptom. Both PSP and CBD are sporadic tauopathies associated with hyperphosphorylated four-repeat tau aggregation in neurons and glial cells. The characteristic pathologies of PSP are midbrain atrophy and the appearance of tufted astrocytes and globose-type neurofibrillary tangles. PSP shows severe degeneration in the globus pallidus, substantia nigra, subthalamic nucleus, and cerebellar dentate nuclei. Conversely, the characteristic pathologies of CBD are cortical atrophy and the appearance of astrocytic plaques and argyrophilic threads. CBD is associated with severe degeneration in the cerebral white matter, substantia nigra, and globus pallidus. Clinical symptoms depend on the topographical distribution and severity of degeneration rather than on the type of aggregated protein or inclusions. PSP and CBD present clinically differential diagnostic difficulties because of their overlapping pathological distributions.     

Corticobasal degeneration: a pathologically distinct 4R tauopathy

Corticobasal degeneration (CBD) is a rare, progressive neurodegenerative disorder with onset in the 5(th) to 7(th) decade of life. It is associated with heterogeneous motor, sensory, behavioral and cognitive symptoms, which make its diagnosis difficult in a living patient. The etiology of CBD is unknown; however, neuropathological and genetic evidence supports a pathogenetic role for microtubule-associated protein tau. CBD pathology is characterized by circumscribed cortical atrophy with spongiosis and ballooned neurons; the distribution of these changes dictates the patient's clinical presentation. Neuronal and glial tau pathology is extensive in gray and white matter of the cortex, basal ganglia, diencephalon and rostral brainstem. Abnormal tau accumulation within astrocytes forms pathognomonic astrocytic plaques. The classic clinical presentation, termed corticobasal syndrome (CBS), comprises asymmetric progressive rigidity and apraxia with limb dystonia and myoclonus. CBS also occurs in conjunction with other diseases, including Alzheimer disease and progressive supranuclear palsy. Moreover, the pathology of CBD is associated with clinical presentations other than CBS, including Richardson syndrome, behavioral variant frontotemporal dementia, primary progressive aphasia and posterior cortical syndrome. Progress in biomarker development to differentiate CBD from other disorders has been slow, but is essential in improving diagnosis and in development of disease-modifying therapies.     

Pathologic heterogeneity in clinically diagnosed corticobasal degeneration.

BACKGROUND: Early reports suggested that corticobasal degeneration (CBD) is a distinct clinicopathologic entity. Because patients have had a fairly consistent constellation of clinical and laboratory findings, many have proposed that the pathologic diagnosis can be surmised with confidence during life. OBJECTIVE: To analyze the pathologic findings in a large series of cases with clinically diagnosed CBD. METHODS: Using the medical research linkage system of the Mayo Clinic for the period January 1990 to December 1997, we identified cases diagnosed during life with CBD who subsequently underwent autopsy. All patients had progressive asymmetric rigidity and apraxia (except one with rigidity but no apraxia) with other findings, suggesting additional cortical and basal ganglionic dysfunction. All cases underwent standardized neuropathologic examination with the distribution and severity of the pathologic changes determined for each case and the pathologic diagnoses based on currently accepted criteria. RESULTS: Thirteen cases were identified. The pathologic diagnoses were CBD in seven, AD in two, and one each for progressive supranuclear palsy, Pick's disease, nonspecific degenerative changes, and Creutzfeldt-Jakob disease. Two cases had negligible basal ganglia and nigral degeneration despite previously having obvious extrapyramidal signs. However, all patients had focal or asymmetric cortical atrophy with coexisting neuronal loss and gliosis with or without status spongiosis, which was maximal in the parietal and frontal cortical regions. CONCLUSIONS: The constellation of clinical features considered characteristic of CBD is associated with heterogeneous pathologies. Furthermore, this syndrome can occur in the absence of basal ganglia and nigral degeneration. The one invariable pathologic abnormality in patients with this syndrome, however, is asymmetric parietofrontal cortical degeneration. At present, accurate diagnosis of CBD requires tissue examination.     

Primitive reflex evaluation in the clinical assessment of extrapyramidal syndromes

The aim of the present study was to evaluate the role of primitive reflexes (PRs) as additional alert sign in routine clinical practice in patients with extrapyramidal syndrome. We considered glabellar, snout, palmomental and grasp reflexes in patients with mild stage of Lewy body dementia (LBD), corticobasal degeneration, progressive supranuclear palsy or Parkinson disease (PD). We also enrolled mild Alzheimer disease (AD) patients, and healthy subjects, as controls. LBD patients showed the highest prevalence of PRs compared with the other groups. The odds ratio of the risk of LBD in PRs ≥ 2 was 27.9 (95% CI 2.9–269.0) compared with control group, 14.6 (95% CI 2.7–79.6) compared with mild AD, and 19.7 (95% CI 3.7–104.3) compared with PD. These data suggest that the occurrence of combination of PRs might be an useful additional warning sign of possible diffuse Lewy body pathology more than other causes of extrapyramidal syndrome.     

“Atypical” atypical parkinsonism: New genetic conditions presenting with features of progressive supranuclear palsy,corticobasal degeneration,or multiple system atrophy—A diagnostic guide

Recently, a number of genetic parkinsonian conditions have been recognized that share some features with the clinical syndromes of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and multiple system atrophy (MSA), the classic phenotypic templates of atypical parkinsonism. For example, patients with progranulin, dynactin, or ATP13A gene mutations may have vertical supranuclear gaze palsy. This has made differential diagnosis difficult for practitioners. In this review, our goal is to make clinicians aware of these genetic disorders and provide clinical clues and syndromic associations, as well as investigative features, that may help in diagnosing these disorders. The correct identification of these patients has important clinical, therapeutic, and research implications. © 2013 Movement Disorder Society     

Increased tau burden in the cortices of progressive supranuclear palsy presenting with corticobasal syndrome.

The objective of this study is to better define the pathological characteristics of pathologically proven progressive supranuclear palsy (PSP) presenting with the corticobasal syndrome (CBS). PSP is characterized by early falls, vertical supranuclear ophthalmoplegia, and axial rigidity, whereas asymmetric limb features, including rigidity, bradykinesia, apraxia, alien limb phenomena, and cortical sensory loss are characteristic of CBS. We investigated clinicopathological characteristics of 5 cases of PSP that presented with CBS (CBS-PSP). Comprehensive pathological analysis was undertaken to determine the presence of concomitant pathological processes as well as quantitative tau burden in cortical regions of CBS-PSP, compared with 8 typical PSP cases (Typ-PSP). The clinical features in the CBS-PSP cases included asymmetrical features, apraxia, alien limb phenomena, and progressive aphasia. All cases had Parkinsonism, and vertical supranuclear ophthalmoplegia was noted in all but 1 case of CBS-PSP. Secondary neuropathological diagnoses included argyrophilic grain disease (AGD) in 1 of the 8 cases of Typ-PSP, whereas Alzheimer's disease (AD), Lewy body disease, AGD, and vascular disease was found in 3 cases of CBS-PSP. Image analysis of cortical tau burden performed in 8 Typ-PSP and 3 CBS-PSP cases revealed a significant increased tau burden in mid-frontal and inferior-parietal cortices in the CBS-PSP cases. This study demonstrates that when PSP presents as CBS, it is most likely due to either a concurrent cortical pathology from a secondary process such as AD or from the primary pathology of PSP extending into cortical areas that are primarily and commonly affected in CBD.     

Atypical parkinsonian syndromes: a general neurologist's perspective

The differential diagnosis of atypical parkinsonian syndromes is challenging. These severe and often rapidly progressive neurodegenerative disorders are clinically heterogeneous and show significant phenotypic overlap. Here, clinical, imaging, neuropathological and genetic features of multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration and frontotemporal lobar degeneration (FTLD) are reviewed. The terms corticobasal degeneration and FTLD refer to pathologically confirmed cases of corticobasal syndrome and frontotemporal dementia (FTD). Frontotemporal lobar degeneration clinically presents as the behavioral variant FTD, semantic variant primary progressive aphasia (PPA), non‐fluent agrammatic variant PPA, logopenic variant PPA and FTD associated with motor neuron disease. While progressive supranuclear palsy and corticobasal syndrome have been called Parkinson‐plus syndromes in the past, they are now classified as FTD‐related disorders, reflecting that they pathologically differ from α‐synucleinopathies like multiple system atrophy and Parkinson disease. The contribution of genetic factors to atypical parkinsonian syndromes is increasingly recognized. Genes involved in the etiology of FTLD include MAPT, GRN and C9orf72. Novel neuroimaging techniques, including tau positron emission tomography imaging, are being investigated. Multimodal magnetic resonance imaging approaches and automated magnetic resonance imaging volume segmentation techniques are being evaluated for optimized differential diagnosis. Current treatment options are symptomatic, and disease modifying therapies are under active investigation.     

Anatomical differences between CBS‐corticobasal degeneration and CBS‐Alzheimer's disease

We compare patterns of gray matter loss on MRI in subjects presenting as corticobasal syndrome (CBS) with Alzheimer disease pathology (CBS‐AD) to those presenting as CBS with corticobasal degeneration pathology (CBS‐CBD). Voxel‐based morphometry was used to compare patterns of gray matter loss in pathologically confirmed CBS‐AD subjects (n = 5) and CBS‐CBD subjects (n = 6) to a group of healthy controls (n = 20), and to each other. Atlas based parcellation using the automated anatomic labeling atlas was also utilized in a region‐of‐interest analysis to account for laterality. The CBS‐AD subjects were younger at the time of scan when compared with CBS‐CBD subjects (median: 60 years vs. 69; P = 0.04). After adjusting for age at time of MRI scan, the CBS‐AD subjects showed loss in posterior frontal, temporal, and superior and inferior parietal lobes, while CBS‐CBD showed more focal loss predominantly in the posterior frontal lobes when compared with controls. In both CBS‐AD and CBS‐CBD groups, there was basal ganglia volume loss, yet relative sparing of hippocampi. On direct comparisons between the two subject groups, CBS‐AD showed greater loss in both temporal and inferior parietal cortices than CBS‐CBD. No regions showed greater loss in the CBS‐CBD group compared to the CBS‐AD group. These findings persisted when laterality was taken into account. In subjects presenting with CBS, prominent temporoparietal, especially posterior temporal and inferior parietal, atrophy may be a clue to the presence of underlying AD pathology. © 2010 Movement Disorder Society