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1.  Grammatical comprehension deficits in non-fluent/agrammatic primary progressive aphasia 
Importance
Grammatical comprehension difficulty is an essential supporting feature of the non-fluent/agrammatic variant of primary progressive aphasia (naPPA), but well-controlled clinical measures of grammatical comprehension are unavailable.
Objective
To develop a measure of grammatical comprehension and examine this comparatively in PPA variants and behavioural-variant frontotemporal degeneration (bvFTD) and to assess the neuroanatomic basis for these deficits with volumetric grey matter atrophy and whole-brain fractional anisotropy (FA) in white matter tracts.
Design
Case–control study.
Setting
Academic medical centre.
Participants
39 patients with variants of PPA (naPPA=12, lvPPA=15 and svPPA=12), 27 bvFTD patients without aphasia and 12 healthy controls.
Main outcome measure
Grammatical comprehension accuracy.
Results
Patients with naPPA had selective difficulty understanding cleft sentence structures, while all PPA variants and patients with bvFTD were impaired with sentences containing a centre-embedded subordinate clause. Patients with bvFTD were also impaired understanding sentences involving short-term memory. Linear regressions related grammatical comprehension difficulty in naPPA to left anterior-superior temporal atrophy and reduced FA in corpus callosum and inferior frontal-occipital fasciculus. Difficulty with centre-embedded sentences in other PPA variants was related to other brain regions.
Conclusions and relevance
These findings emphasise a distinct grammatical comprehension deficit in naPPA and associate this with interruption of a frontal-temporal neural network.
doi:10.1136/jnnp-2013-305749
PMCID: PMC3925677  PMID: 24039027
2.  The Organization and Anatomy of Narrative Comprehension and Expression in Lewy Body Spectrum Disorders 
Neuropsychology  2012;26(3):368-384.
Objective
Patients with Lewy body spectrum disorders (LBSD) such as Parkinson’s disease (PD), Parkinson’s disease with dementia (PDD), and dementia with Lewy bodies (DLB) exhibit deficits in both narrative comprehension and narrative expression. The present research examines the hypothesis that these impairments are due to a material-neutral deficit in organizational executive resources rather than to impairments of language per se. We predicted that comprehension and expression of narrative would be similarly affected and that deficits in both expression and comprehension of narrative would be related to the same anatomic distribution of prefrontal disease.
Method
We examined 29 LBSD patients and 26 healthy seniors on their comprehension and expression of narrative discourse. For comprehension, we measured accuracy and latency in judging events with high and low associativity from familiar scripts such as “going fishing.” The expression task involved maintaining the connectedness of events while narrating a story from a wordless picture book.
Results
LBSD patients were impaired on measures of narrative organization during both comprehension and expression relative to healthy seniors. Measures of organization during narrative expression and comprehension were significantly correlated with each other. These measures both correlated with executive measures but not with neuropsychological measures of lexical semantics or grammar. Voxel-based morphometry revealed overlapping regressions relating frontal atrophy to narrative comprehension, narrative expression, and measures of executive control.
Conclusions
Difficulty with narrative discourse in LBSD stems in part from a deficit of organization common to comprehension and expression. This deficit is related to prefrontal cortical atrophy in LBSD.
doi:10.1037/a0027115
PMCID: PMC3348419  PMID: 22309984
Parkinson’s disease; speech; language; dementia with Lewy bodies
3.  SENTENCE PROCESSING IN LEWY BODY SPECTRUM DISORDER: THE ROLE OF WORKING MEMORY 
Brain and Cognition  2012;78(2):85-93.
Prior work has related sentence processing to executive deficits in non-demented patients with Parkinson’s disease (PD). We extended this investigation to patients with dementia with Lewy bodies (DLB) and PD dementia (PDD) by examining grammatical and working memory components of sentence processing in the full range of patients with Lewy body spectrum disorder (LBSD). Thirty-three patients with LBSD were given a two-alternative, forced-choice sentence-picture matching task. Sentence type, working memory, and grammatical structure were systematically manipulated in the sentences. We found that patients with PDD and DLB were significantly impaired relative to non-demented PD patients and healthy controls. The deficit in PDD/DLB was most pronounced for sentences lengthened by the strategic placement of an additional prepositional phrase and for sentences with an additional proposition due to a center-embedded clause. However, there was no effect for subject-relative versus object-relative grammatical structure. An MRI voxel-based morphometry analysis in a subset of patients showed significant gray matter thinning in the frontal lobe bilaterally, and this extended to temporal, parietal and occipital regions. A regression analysis related sentence processing difficulty in LBSD to frontal neocortex, including inferiorprefrontal, premotor, and dorsolateral prefrontal regions, as well as right superior temporal cortex. These findings are consistent with the hypothesis that patients with PDD and DLB have difficulty processing sentences with increased working memory demands and that this deficit is related in part to their frontal disease.
doi:10.1016/j.bandc.2011.12.004
PMCID: PMC3265703  PMID: 22218297
Lewy body; Parkinson’s; sentence processing; working memory; MRI; prefrontal
4.  Impairments of Speech Fluency in Lewy Body Spectrum Disorder 
Brain and Language  2011;120(3):290-302.
Few studies have examined connected speech in demented and non-demented patients with Parkinson’s disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions.
doi:10.1016/j.bandl.2011.09.004
PMCID: PMC3299896  PMID: 22099969
Parkinson’s disease; speech; language; fluency; dementia with Lewy bodies
5.  The Organization of Narrative Discourse in Lewy Body Spectrum Disorder 
Brain and language  2011;119(1):30-41.
Narrative discourse is an essential component of day-to-day communication, but little is known about narrative in Lewy Body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's disease with dementia (PDD), and dementia with Lewy bodies (DLB). We performed a detailed analysis of a semi-structured speech sample in 32 non-aphasic patients with LBSD, and we related their narrative impairments to gray matter (GM) atrophy using voxel-based morphometry. We found that patients with PDD and DLB have significant difficulty organizing their narrative speech. This was correlated with deficits on measures of executive functioning and speech fluency. Regression analyses associated this deficit with reduced cortical volume in inferior frontal and anterior cingulate regions. These findings are consistent with a model of narrative discourse that includes executive as well as language components and with an impairment of the organizational component of narrative discourse in patients with PDD and DLB.
doi:10.1016/j.bandl.2011.05.006
PMCID: PMC3163000  PMID: 21689852
Parkinson's disease; discourse; speech; language; Dementia with Lewy bodies
6.  Non-Fluent Speech in Frontotemporal Lobar Degeneration 
Journal of neurolinguistics  2009;22(4):370-383.
We investigated the cognitive and neural bases of impaired speech fluency, a central feature of primary progressive aphasia. Speech fluency was assessed in 35 patients with frontotemporal lobar degeneration (FTLD) who presented with progressive non-fluent aphasia (PNFA, n=11), semantic dementia (SemD, n=12), or a social and executive disorder without aphasia (SOC/EXEC, n=12). Fluency was quantified as the number of words per minute in an extended, semi-structured speech sample. This was related to language characteristics of the speech sample and to neuropsychological measures. PNFA patients were significantly less fluent than controls and other FTLD patients. Fluency correlated with grammatical expression but not with speech errors or executive difficulty. SemD and SOC/EXEC patients were also less fluent than controls. In SemD, fluency was associated with semantically limited content. In SOC/EXEC, fluency was associated with executive limitations. Voxel-based morphometry analyses of high-resolution MRI related fluency to gray matter volume in left inferior frontal, insula, and superior temporal regions for the entire cohort of FTLD patients. This region overlapped partially distinct atrophic areas in each FTLD subgroup. It thus appears to play a crucial role in speech fluency, which can be interrupted in different ways in different FTLD subgroups.
doi:10.1016/j.jneuroling.2008.12.001
PMCID: PMC3238501  PMID: 22180700
frontotemporal dementia; progressive aphasia; MRI; speech fluency
7.  The New Classification of Primary Progressive Aphasia into Semantic, Logopenic, or Nonfluent/Agrammatic Variants 
Primary progressive aphasia (PPA), typically resulting from a neurodegenerative disease such as frontotemporal lobar degeneration or Alzheimer’s disease, is characterized by a progressive loss of specific language functions with relative sparing of other cognitive domains. Three variants of PPA are now recognized: semantic variant, logopenic variant, and nonfluent/agrammatic variant. We discuss recent work characterizing the neurolinguistic, neuropsychological, imaging and pathologic profiles associated with these variants. Improved reliability of diagnoses will be increasingly important as trials for etiology-specific treatments become available. We also discuss the implications of these syndromes for theories of language function.
doi:10.1007/s11910-010-0140-4
PMCID: PMC2963791  PMID: 20809401
Primary progressive aphasia (PPA); Semantic variant PPA (svPPA); Semantic dementia (SD); Semantic PPA (PPA-S); Logopenic variant PPA (lvPPA); Logopenic progressive aphasia (LPA); Logopenic PPA (PPA-L); Nonfluent/agrammatic variant PPA (navPPA); Progressive nonfluent aphasia (PNFA); Agrammatic PPA (PPA-G); Frontotemporal dementia (FTD, FTLD); Alzheimer’s disease (AD)
8.  SPEECH ERRORS IN PROGRESSIVE NON-FLUENT APHASIA 
Brain and language  2010;113(1):13-20.
The nature and frequency of speech production errors in neurodegenerative disease have not previously been precisely quantified. In the present study, 16 patients with a progressive form of nonfluent aphasia (PNFA) were asked to tell a story from a wordless children’s picture book. Errors in production were classified as either phonemic, involving language-based deformations that nevertheless result in possible sequences of English speech segments; or phonetic, involving a motor planning deficit and resulting in non-English speech segments. The distribution of cortical atrophy as revealed by structural MRI scans was examined quantitatively in a subset of PNFA patients (N=7). The few errors made by healthy seniors were only phonemic in type. PNFA patients made more than four times as many errors as controls. This included both phonemic and phonetic errors, with a preponderance of errors (82%) classified as phonemic. The majority of phonemic errors were substitutions that shared most distinctive features with the target phoneme. The systematic nature of these substitutions is not consistent with a motor planning deficit. Cortical atrophy was found in prefrontal regions bilaterally and peri-Sylvian regions of the left hemisphere. We conclude that the speech errors produced by PNFA patients are mainly errors at the phonemic level of language processing and are not caused by a motor planning impairment.
doi:10.1016/j.bandl.2009.12.001
PMCID: PMC2839014  PMID: 20074786
Progressive non-fluent aphasia; phonology; speech errors
9.  Impaired Information Integration Contributes to Communication Difficulty in Corticobasal Syndrome 
Objective
To investigate the cognitive and neural correlates of discourse impairment in corticobasal syndrome (CBS).
Background
Difficulty communicating is a frequent clinical manifestation in patients with CBS. However, the mechanisms underlying this disabling problem are not well understood.
Methods
Twenty patients with CBS and 8 healthy seniors narrated a picture story. Narratives were analyzed for maintenance of the narrative theme, identification of the overall point of the story (global connectedness), and connectedness between consecutive events (local connectedness). Discourse measures were correlated with performance on cognitive tasks and with cortical atrophy as determined by magnetic resonance imaging voxel-based morphometry.
Results
Patients with CBS referred to the narrative theme significantly less frequently than controls. Global connectedness was intact in only 6 of 20 CBS patients (30%), but preserved in all controls. Local connectedness was significantly diminished in patients relative to controls. Discourse performance in CBS was related to tasks requiring higher-order integration of visual material, but not to basic visuospatial/visuoperceptual, language, or memory function. Discourse impairment was directly related to atrophy in the right parietal lobe and bilateral dorsolateral prefrontal cortex.
Conclusions
Our findings suggest that impaired information integration in CBS, related to parieto-frontal disease, interferes with patients’ ability to narrate a coherent story.
doi:10.1097/WNN.0b013e3181c5e2f8
PMCID: PMC2930985  PMID: 20299856
corticobasal syndrome; volumetric MRI; discourse; inferior parietal lobe; dorsolateral prefrontal cortex

Results 1-9 (9)