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ObjectiveTo describe clinical and pathologic characteristics of corticobasal degeneration (CBD) with cognitive predominant problems during the disease course.MethodsIn a series of autopsy-confirmed cases of CBD, we identified patients with cognitive rather than motor predominant features (CBD-Cog), including 5 patients thought to have Alzheimer disease (AD) and 10 patients thought to have behavioral variant frontotemporal dementia (FTD). We compared clinical and pathologic features of CBD-Cog with those from a series of 31 patients with corticobasal syndrome (CBD-CBS). For pathologic comparisons between CBD-Cog and CBD-CBS, we used semiquantitative scoring of neuronal and glial lesion types in multiple brain regions and quantitative assessments of tau burden from image analysis.ResultsFive of 15 patients with CBD-Cog never had significant motor problems during their disease course. The most common cognitive abnormalities in CBD-Cog were executive and visuospatial dysfunction. The frequency of language problems did not differ between CBD-Cog and CBD-CBS. Argyrophilic grain disease, which is a medial temporal tauopathy associated with mild cognitive impairment, was more frequent in CBD-Cog. Apathy was also more frequent in CBD-Cog. Tau pathology in CBD-Cog was greater in the temporal and less in perirolandic cortices than in CBD-CBS.ConclusionA subset of patients with CBD has a cognitive predominant syndrome than can be mistaken for AD or FTD. Our findings suggest that distribution of tau cortical pathology (greater in temporal and less in perirolandic cortices) may be the basis of this uncommon clinical variant of CBD.

Objective: To use multiple serial MRI to assess rates and trajectories of brain and hippocampal atrophy in subjects with frontotemporal dementia (FTD) with progranulin (GRN) or microtubule-associated protein tau (MAPT) gene mutations. Methods: In this case-control study, we identified 8 subjects with mutations in GRN and 12 subjects with mutations in MAPT who had at least 2 serial MRIs. Serial MRIs were registered to baseline MRI for each subject using 9 df registration and rate of whole brain atrophy was calculated using the boundary-shift integral. Hippocampal volume was measured using Freesurfer. Mixed effects linear regression models were used to model volume change over time in both groups after adjusting for head size, age at baseline, and disease duration at baseline. Results: The annual rate of whole brain atrophy in the MAPT subjects was 2.4% per year (95% confidence interval [CI] 1.9-2.8). The GRN subjects showed a higher rate of whole brain atrophy at 3.5% per year (95% CI 2.8-4.2; p = 0.01). Rates of hippocampal atrophy were not different across the groups (MAPT = 7.8% [95% CI 3.9-12], GRN = 6.5% [95% CI 1.7-11], p = 0.66). Rates of whole brain atrophy in GRN, and hippocampal atrophy in MAPT, were associated with age, with older subjects showing slower rates of atrophy (p = 0.01 and p = 0.001). Conclusions: Subjects with FTD with GRN mutations have a faster rate of whole brain atrophy than subjects with FTD with MAPT mutations, with similar rates of hippocampal atrophy. Rates of atrophy in both groups were associated with age. These findings are important for future treatment trials in FTD that use rates of atrophy as an outcome measure. Neurology (R) 2011; 77: 393-398

Background: Corticobasal syndrome (CBS) can be associated with different underlying pathologies that are difficult to predict based on clinical presentation. The aim of this study was to determine whether patterns of atrophy on imaging could be useful to help predict underlying pathology in CBS. Methods: This was a case-control study of 24 patients with CBS who had undergone MRI during life and came to autopsy. Pathologic diagnoses included frontotemporal lobar degeneration (FTLD) with TDP-43 immunoreactivity in 5 (CBS-TDP), Alzheimer disease (AD) in 6 (CBS-AD), corticobasal degeneration in 7 (CBS-CBD), and progressive supranuclear palsy in 6 (CBS-PSP). Voxel-based morphometry and atlas-based parcellation were used to assess atrophy across the CBS groups and compared to 24 age- and gender-matched controls. Results: All CBS pathologic groups showed gray matter loss in premotor cortices, supplemental motor area, and insula on imaging. However, CBS-TDP and CBS-AD showed more widespread patterns of loss, with frontotemporal loss observed in CBS-TDP and temporoparietal loss observed in CBS-AD. CBS-TDP showed significantly greater loss in prefrontal cortex than the other groups, whereas CBS-AD showed significantly greater loss in parietal lobe than the other groups. The focus of loss was similar in CBS-CBD and CBS-PSP, although more severe in CBS-CBD. Conclusions: Imaging patterns of atrophy in CBS vary according to pathologic diagnosis. Widespread atrophy points toward a pathologic diagnosis of FTLD-TDP or AD, with frontotemporal loss suggesting FTLD-TDP and temporoparietal loss suggesting AD. On the contrary, more focal atrophy predominantly involving the premotor and supplemental motor area suggests CBD or PSP pathology.

Objective: To use diffusion tensor imaging (DTI) to assess gray matter and white matter tract diffusion in behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SMD), and progressive nonfluent aphasia (PNFA). Methods: This was a case-control study where 16 subjects with bvFTD, 7 with PNFA, and 4 with SMD were identified and matched by age and gender to 19 controls. All subjects had 3-T head MRI with a DTI sequence with diffusion encoding in 21 directions. Gray matter mean diffusivity (MD) was assessed using a region-of-interest (ROI) and voxel-level approach, and voxel-based morphometry was used to assess patterns of gray matter loss. White matter tract diffusivity (fractional anisotropy and radial diffusivity) was assessed by placing ROIs on tracts of interest. Results: In bvFTD, increased gray matter MD and gray matter loss were identified bilaterally throughout frontal and temporal lobes, with abnormal diffusivity observed in white matter tracts that connect to these regions. In SMD, gray matter loss and increased MD were identified predominantly in the left temporal lobe, with tract abnormalities observed in the inferior longitudinal fasciculus and uncinate fasciculus. In PNFA, gray matter loss and increased MD were observed in left inferior frontal lobe, insula, and supplemental motor area, with tract abnormalities observed in the superior longitudinal fasciculus. Conclusions: The diffusivity of gray matter is increased in regions that are atrophic in frontotemporal dementia, suggesting disruption of the cytoarchitecture of remaining tissue. Furthermore, damage was identified in white matter tracts that interconnect these regions, supporting the hypothesis that these diseases involve different and specific brain networks.

Background: Neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau proteins, are one of the pathologic hallmarks of Alzheimer disease (AD). We aimed to determine whether patterns of gray matter atrophy from antemortem MRI correlate with Braak staging of NFT pathology. Methods: Eighty-three subjects with Braak stage III through VI, a pathologic diagnosis of low- to high-probability AD, and MRI within 4 years of death were identified. Voxel-based morphometry assessed gray matter atrophy in each Braak stage compared with 20 pathologic control subjects (Braak stages 0 through II). Results: In pairwise comparisons with Braak stages 0 through II, a graded response was observed across Braak stages V and VI, with more severe and widespread loss identified at Braak stage VI. No regions of loss were identified in Braak stage III or IV compared with Braak stages 0 through II. The lack of findings in Braak stages III and IV could be because Braak stage is based on the presence of any NFT pathology regardless of severity. Actual NFT burden may vary by Braak stage. Therefore, tau burden was assessed in subjects with Braak stages 0 through IV. Those with high tau burden showed greater gray matter loss in medial and lateral temporal lobes than those with low tau burden. Conclusions: Patterns of gray matter loss are associated with neurofibrillary tangle (NFT) pathology, specifically with NFT burden at Braak stages III and IV and with Braak stage itself at higher stages. This validates three-dimensional patterns of atrophy on MRI as an approximate in vivo surrogate indicator of the full brain topographic representation of the neurodegenerative aspect of Alzheimer disease pathology.

Background: Leukoencephalopathy with neuroaxonal spheroids is a rare cause of severe, subacute dementia that usually presents in childhood and is inherited in an autosomal dominant pattern. The authors present clinical, radiologic, and pathologic features of adult-onset, sporadic cases mimicking cerebral-type progressive MS. Methods: Five patients referred to an MS subspecialty clinic from 1999 to 2006 suspected of having primary cerebral MS. All patients were reviewed clinically, radiologically, and pathologically at Mayo Clinic Rochester. Diagnostic brain biopsies were examined by two neuropathologists. Results: All patients had severe, progressive cognitive and motor impairment, often with prominently asymmetrical features and diffuse nonenhancing subcortical white matter lesions on brain MRI. Cerebrovascular and spinal cord imaging were normal. CSF showed elevated neuron-specific enolase without elevated oligoclonal bands or IgG index. Extensive evaluations for alternative diagnoses were unrevealing. Pathologic examination confirmed leukodystrophy with neuroaxonal spheroids and pigmented glia on all patients. Therapies initiated did not alter the severe progressive disease course. Conclusions: Leukoencephalopathy with neuroaxonal spheroids occurs sporadically, in adults, and mimics cerebral-type MS or other leukodystrophies. Brain biopsy may be diagnostic in life; however, no treatment is known to be effective. Pathologic diagnosis is important to avoid potentially toxic therapies aimed at CNS inflammatory diseases such as MS. GLOSSARY: FLAIR = fluid attenuation inversion recovery; NSE = neuron-specific enolase.

Background: Chronic liver failure may be associated with pallidal MRI T1 hyperintensity and heterogeneous neurologic syndromes, including parkinsonism, cognitive impairment, and others. Manganese accumulation may be responsible for the imaging and clinical findings. Objective: To measure manganese plus other metal concentrations in pallidum and additional brain regions and to examine the corresponding neuropathology in cases of chronic liver failure. Methods: Regional brain metal concentrations were measured in seven chronic liver failure cases, four with pallidal T1 hyperintensity and three with normal MRI, plus five controls. Neuropathologic examination employed α-synuclein and tau immunohistochemistry. Results: In patients with pallidal T1 hyperintensity, pallidal manganese concentrations were increased sevenfold over controls and over fourfold vs liver patients with normal MRI; manganese concentrations were also significantly elevated in all other brain regions. Copper was additionally increased in all brain regions, whereas other metal concentrations were similar to control values. Neuropathology revealed mild to moderate Alzheimer type II gliosis in the liver failure groups and negative α-synuclein and tau immunostaining except for one case (intermediate Alzheimer disease pathology). Conclusion: In chronic liver failure, manganese accumulation is responsible for the pallidal MRI T1 hyperintensity. Pallidal copper was also elevated in affected cases, but copper does not have the paramagnetic properties to generate isolated T1 hyperintensity. Basal ganglia manganese or copper accumulation may be responsible for the parkinsonism sometimes seen in chronic liver failure. Pallidal MRI T1 hyperintensity is a biomarker of manganese overload.

Pathologic changes in the superior cerebellar peduncles (SCP) are common in progressive supranuclear palsy (PSP), but atrophy of the SCP has never been systematically studied.To investigate the SCP width in PSP cases and controls with morphometric methods.The mean width of the SCP in transverse sections of the pons at the level of trigeminal nerve was determined in 48 PSP cases (29 men, 19 women; mean age 72.5 +/- 8.2 years) and 29 age-matched control subjects, many with neurodegenerative disorders that can be clinically mistaken for PSP. As the origin of the SCP is the cerebellar dentate nucleus, correlations were sought between SCP atrophy and severity of grumose degeneration in the dentate nucleus.The average width of the SCP was less in PSP (range 0.09 to 0.24 cm) than in controls (range 0.21 to 0.43 cm; Mann-Whitney U test, p0.001), including control cases that had been clinically misdiagnosed as PSP (range 0.26 to 0.41 cm). Severity of SCP atrophy normalized by brain weight correlated with disease duration (Spearman rank order correlation, r = 0.367, p = 0.028), suggesting that SCP atrophy is a relatively early feature of PSP. No correlation was found between grumose degeneration and SCP width.SCP atrophy is common in PSP and correlates with disease duration. Given that measurements of the SCP are within the resolution of MRI, it remains to be determined if SCP atrophy can be used as a diagnostic marker of PSP.

The authors assessed the frequency of spinal cord α-synuclein pathology in neurologically asymptomatic individuals older than 60 years of age (N = 106). Using α-synuclein immunohistochemistry, nine cases (8%) had incidental Lewy neurites in the intermediolateral column and at least some α-synuclein pathology in the dorsal motor nucleus of the vagus, locus ceruleus, and central raphe nucleus. Sparse α-synuclein pathology was also detected in the substantia nigra, basal forebrain, amygdala, or cortex in all but two cases.