Dataset Information

Multimodal predictors for Alzheimer disease in nonfluent primary progressive aphasia.

ABSTRACT:

Objective

Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) are hypothesized to cause clinically distinct forms of primary progressive aphasia (PPA) that predominantly affect expressive speech. AD is thought to cause logopenic progressive aphasia (LPA), and FTLD may cause progressive nonfluent aphasia (PNFA). We sought to determine the value of clinical characterization, neuropsychological analysis, and MRI atrophy in predicting pathology of LPA and PNFA.

Methods

Patients with LPA (n = 19) and patients with PNFA (n = 19) were evaluated with neuropsychological assessments, structural MRI, CSF analysis, and neuropathologic examination.

Results

Twelve of 19 patients with LPA (63%) and 6 of 19 patients with PNFA (32%) had neuropathologic findings or CSF biomarkers consistent with AD. Neuropsychological testing showed that naming was more impaired in patients with AD, and letter-guided fluency was more affected in patients with a non-AD disorder. Voxel-based morphometry analysis revealed that in patients with AD, patients with LPA and PNFA had significant posterior-superior temporal atrophy; in patients with non-AD, patients with LPA had peri-Sylvian atrophy and patients with PNFA had dorsolateral prefrontal and insular atrophy. Receiver operator characteristic curve analysis showed that combining neuropsychological testing with MRI atrophy pattern had 90% specificity for pathology or CSF biomarkers consistent with AD, and combining clinical features with neuropsychological analysis had 100% sensitivity for pathology or CSF biomarkers consistent with AD.

Conclusions

Neither PPA phenotyping nor imaging alone is a reliable predictor of pathology. Multimodal predictors, such as combining neuropsychological testing with MRI analysis, can improve noninvasive prediction of underlying pathology in nonfluent forms of PPA.

SUBMITTER: Hu WT

PROVIDER: S-EPMC2931765 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature

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Publications

Multimodal predictors for Alzheimer disease in nonfluent primary progressive aphasia.

Hu W T WT McMillan C C Libon D D Leight S S Forman M M Lee V M-Y VM Trojanowski J Q JQ Grossman M M

Neurology 20100801 7

<h4>Objective</h4>Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) are hypothesized to cause clinically distinct forms of primary progressive aphasia (PPA) that predominantly affect expressive speech. AD is thought to cause logopenic progressive aphasia (LPA), and FTLD may cause progressive nonfluent aphasia (PNFA). We sought to determine the value of clinical characterization, neuropsychological analysis, and MRI atrophy in predicting pathology of LPA and PNFA.<h4>Methods</h4 ...[more]

PMID: 20713948

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Project description:Crossed aphasia has been reported mainly as post-stroke aphasia resulting from brain damage ipsilateral to the dominant right hand. Here, we described a case of a crossed nonfluent/agrammatic primary progressive aphasia (nfvPPA), who developed a corticobasal syndrome (CBS). We collected clinical, cognitive, and neuroimaging data for four consecutive years from a 55-year-old right-handed lady (JV) presenting with speech disturbances. 18-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) and DaT-scan with (123)I-Ioflupane were obtained. Functional MRI (fMRI) during a verb naming task was acquired to characterize patterns of language lateralization. Diffusion tensor MRI was used to evaluate white matter damage within the language network. At onset, JV presented with prominent speech output impairment and right frontal atrophy. After 3 years, language deficits worsened, with the occurrence of a mild agrammatism. The patient also developed a left-sided mild extrapyramidal bradykinetic-rigid syndrome. The clinical picture was suggestive of nfvPPA with mild left-sided extrapyramidal syndrome. At this time, voxel-wise SPM analyses of (18)F-FDG PET and structural MRI showed right greater than left frontal hypometabolism and damage, which included the Broca's area. DaT-scan showed a reduced uptake in the right striatum. FMRI during naming task demonstrated bilateral language activations, and tractography showed right superior longitudinal fasciculus (SLF) involvement. Over the following year, JV became mute and developed frank left-sided motor signs and symptoms, evolving into a CBS clinical picture. Brain atrophy worsened in frontal areas bilaterally, and extended to temporo-parietal regions, still with a right-sided asymmetry. Tractography showed an extension of damage to the left SLF and right inferior longitudinal fasciculus. We report a case of crossed nfvPPA followed longitudinally and studied with advanced neuroimaging techniques. The results highlight a complex interaction between individual premorbid developmental differences and the clinical phenotype.

Project description:BackgroundA subset of patients with the nonfluent variant of primary progressive aphasia (PPA) exhibit concomitant single-word comprehension problems, constituting a 'mixed variant' phenotype. This phenotype is rare and currently not fully characterized. The aim of this study was twofold: to assess the prevalence and nature of single-word comprehension problems in the nonfluent variant and to study multimodal imaging characteristics of atrophy, tau, and amyloid burden associated with this mixed phenotype.MethodsA consecutive memory-clinic recruited series of 20 PPA patients (12 nonfluent, five semantic, and three logopenic variants) were studied on neurolinguistic and neuropsychological domains relative to 64 cognitively intact healthy older control subjects. The neuroimaging battery included high-resolution volumetric magnetic resonance imaging processed with voxel-based morphometry, and positron emission tomography with the tau-tracer [18F]-THK5351 and amyloid-tracer [11C]-Pittsburgh Compound B.ResultsSeven out of 12 subjects who had been classified a priori with nonfluent variant PPA showed deficits on conventional single-word comprehension tasks along with speech apraxia and agrammatism, corresponding to a mixed variant phenotype. These mixed variant cases included three females and four males, with a mean age at onset of 65 years (range 44-77 years). Object knowledge and object recognition were additionally affected, although less severely compared with the semantic variant. The mixed variant was characterized by a distributed atrophy pattern in frontal and temporoparietal regions. A more focal pattern of elevated [18F]-THK5351 binding was present in the supplementary motor area, the left premotor cortex, midbrain, and basal ganglia. This pattern was closely similar to that seen in pure nonfluent variant PPA. At the individual patient level, elevated [18F]-THK5351 binding in the supplementary motor area and premotor cortex was present in six out of seven mixed variant cases and in five and four of these cases, respectively, in the thalamus and midbrain. Amyloid biomarker positivity was present in two out of seven mixed variant cases, compared with none of the five pure nonfluent cases.ConclusionsA substantial proportion of PPA patients with speech apraxia and agrammatism also have single-word comprehension deficits. At the neurobiological level, the mixed variant shows a high degree of similarity with the pure nonfluent variant of PPA.Trial registrationEudraCT, 2014-002976-10 . Registered on 13-01-2015.

Project description:ImportanceDespite being characterized as a disorder of language production, nonfluent/agrammatic variant primary progressive aphasia (nfvPPA) is frequently associated with auditory symptoms. However, to our knowledge, peripheral auditory function has not been defined in this condition.ObjectiveTo assess peripheral hearing function in individuals with nfvPPA compared with healthy older individuals and patients with Alzheimer disease (AD).Design, setting, and participantsThis cross-sectional single-center study was conducted at the Dementia Research Centre of University College London between August 2015 and July 2018. A consecutive cohort of patients with nfvPPA and patients with AD were compared with healthy control participants. No participant had substantial otological or cerebrovascular disease; all eligible patients fulfilling diagnostic criteria and able to comply with audiometry were included.Main outcomes and measuresWe measured mean threshold sound levels required to detect pure tones at frequencies of 500, 1000, 2000, 4000, and 6000 Hz in the left and right ears separately; these were used to generate better-ear mean and worse-ear mean composite hearing threshold scores and interaural difference scores for each participant. All analyses were adjusted for participant age.ResultsWe studied 19 patients with nfvPPA (9 female; mean [SD] age, 70.3 [9.0] years), 20 patients with AD (9 female; mean [SD] age, 69.4 [8.1] years) and 34 control participants (15 female; mean [SD] age, 66.7 [6.3] years). The patients with nfvPPA had significantly higher scores than control participants on better-ear mean scores (patients with nfvPPA: mean [SD], 36.3 [9.4] decibels [dB]; control participants: 28.9 [7.3] dB; age-adjusted difference, 5.7 [95% CI, 1.4-10.0] dB; P = .01) and worse-ear mean scores (patients with nfvPPA: 42.2 [11.5] dB; control participants: 31.7 [8.1] dB; age-adjusted difference, 8.5 [95% CI, 3.6-13.4] dB; P = .001). The patients with nfvPPA also had significantly higher better-ear mean scores than patients with AD (patients with AD: mean [SD] 31.1 [7.5] dB; age-adjusted difference, 4.8 [95% CI, 0.0-9.6] dB; P = .048) and worse-ear mean scores (patients with AD: mean [SD], 33.8 [8.2] dB; age-adjusted difference, 7.8 [95% CI, 2.4-13.2] dB; P = .005). The difference scores (worse-ear mean minus better-ear mean) were significantly higher in the patients with nfvPPA (mean [SD], 5.9 [5.2] dB) than control participants (mean [SD], 2.8 [2.2] dB; age-adjusted difference, 2.8 [95% CI, 0.9-4.7] dB; P = .004) and patients with AD (mean [SD], 2.8 [2.1] dB; age-adjusted difference, 3.0 [95% CI, 0.9-5.1] dB; P = .005).Conclusions and relevanceIn this study, patients with nfvPPA performed worse on pure-tone audiometry than healthy older individuals or patients with AD, and the difference was not attributable to age or general disease factors. Cases of nfvPPA were additionally associated with increased functional interaural audiometric asymmetry. These findings suggest conjoint peripheral afferent and more central regulatory auditory dysfunction in individuals with nfvPPA.

Dataset Information

Multimodal predictors for Alzheimer disease in nonfluent primary progressive aphasia.

Objective

Methods

Results

Conclusions

Publications

Multimodal predictors for Alzheimer disease in nonfluent primary progressive aphasia.

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