Dementia with Lewy bodies presenting as Logopenic variant primary progressive Aphasia

Turning the Spotlight to Cholinergic Pharmacotherapy of the Human Language System

Even though language is essential in human communication, research on pharmacological therapies for language deficits in highly prevalent neurodegenerative and vascular brain diseases has received little attention. Emerging scientific evidence suggests that disruption of the cholinergic system may play an essential role in language deficits associated with Alzheimer's disease and vascular cognitive impairment, including post-stroke aphasia. Therefore, current models of cognitive processing are beginning to appraise the implications of the brain modulator acetylcholine in human language functions. Future work should be directed further to analyze the interplay between the cholinergic system and language, focusing on identifying brain regions receiving cholinergic innervation susceptible to modulation with pharmacotherapy to improve affected language domains. The evaluation of language deficits in pharmacological cholinergic trials for Alzheimer's disease and vascular cognitive impairment has thus far been limited to coarse-grained methods. More precise, fine-grained language testing is needed to refine patient selection for pharmacotherapy to detect subtle deficits in the initial phases of cognitive decline. Additionally, noninvasive biomarkers can help identify cholinergic depletion. However, despite the investigation of cholinergic treatment for language deficits in Alzheimer's disease and vascular cognitive impairment, data on its effectiveness are insufficient and controversial. In the case of post-stroke aphasia, cholinergic agents are showing promise, particularly when combined with speech-language therapy to promote trained-dependent neural plasticity. Future research should explore the potential benefits of cholinergic pharmacotherapy in language deficits and investigate optimal strategies for combining these agents with other therapeutic approaches.

Aphasic mild cognitive impairment in prodromal dementia with Lewy bodies

Introduction

This study aimed to determine the characteristics of aphasic mild cognitive impairment (aphasic MCI), which is characterized by a progressive and relatively prominent language impairment compared with other cognitive impairments, in the prodromal phase of dementia with Lewy bodies (DLB).

Methods

Of the 26 consecutive patients with aphasic MCI who had been prospectively recruited at our hospital, 8 patients were diagnosed with prodromal DLB and underwent language, neurological, neuropsychological, and neuroimaging (N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography; IMP-SPECT) testing. Three of these patients also underwent cholinesterase inhibitor therapy with donepezil.

Results

In our aphasic MCI cohort, the clinical diagnosis of probable prodromal DLB accounted for more than 30% of cases; therefore, the presence of language impairment in prodromal DLB was not very uncommon. Five patients were diagnosed with progressive anomic aphasia and three with logopenic progressive aphasia. Anomic aphasia was characterized by apparent anomia but relatively preserved repetition and comprehension ability and logopenic progressive aphasia by anomia, phonemic paraphasia, and impaired repetition. IMP-SPECT revealed hypoperfusion of the temporal and parietal lobes in the left hemisphere in all but one patient. All patients who underwent cholinesterase inhibitor therapy with donepezil showed improvement in general cognitive function, including language function.

Discussion

The clinical and imaging features of aphasic MCI in prodromal DLB are similar to those observed in Alzheimer's disease. Progressive fluent aphasia, such as progressive anomic aphasia and logopenic progressive aphasia, is one of the clinical presentations in prodromal state of DLB. Our findings provide further insight into the clinical spectrum of prodromal DLB and may contribute to the development of medication for progressive aphasia caused by cholinergic insufficiency.

Diffuse Lewy body disease presenting as Parkinson's disease with progressive aphasia

Primary progressive aphasia (PPA) is a progressive language disorder often due to an underlying neurodegenerative disease. The most common pathologies associated with PPA include frontotemporal lobar degeneration (FTLD)-tau, FTLD-associated with transactivation response DNA-binding protein of 43 kDa (TDP-43) (FTLD-TDP), and Alzheimer's disease (AD). Accumulating evidence has suggested that Lewy body disease (LBD) can also be associated with PPA. We herein report a 78-year-old Caucasian woman who initially presented with levodopa-responsive parkinsonism at age 67 and later developed cognitive impairment, visual hallucinations, rapid eye movement sleep behavior disorder, and progressive aphasia, characterized by reduced spontaneous speech, word-finding difficulty, and difficulties in writing and reading. ¹⁸ Fluorodeoxyglucoase (FDG)-positron emission tomography (PET) performed at the age of 73 years identified hypometabolism in the frontal (right > left), temporal (left > right), and parietal (left > right) lobes. Neuropathological assessment revealed diffuse LBD (DLBD), AD, and TDP-43 stage 6 with prehippocampal sclerosis. Senile plaques were numerous, but only a few neurofibrillary tangles were present in the neocortex. The Braak neurofibrillary tangle stage was IV, and the Thal amyloid phase was 3. Lewy-related pathology was severe in the neocortex, as well as limbic cortices, basal forebrain, amygdala, and brainstem. Compared to 166 DLBD cases with a clinical diagnosis of dementia with Lewy bodies (DLB), the Lewy body count of the patient in this report was highest in the inferior parietal cortex, followed by midfrontal and superior temporal cortices. The findings suggest that severe cortical LBD pathology has contributed to her progressive aphasia. Autopsy cases of LBD presenting as PPA have been reported, but patients with PD and autopsy-proven DLBD who later developed progressive aphasia have not been reported. Our findings indicate that PD can be associated with progressive aphasia later in the disease course. Although uncommon, LBD should be considered as a differential diagnosis of progressive aphasia.

Lewy Body Disease is a Contributor to Logopenic Progressive Aphasia Phenotype

OBJECTIVE

The objective of this study was to describe clinical features, [18 F]-fluorodeoxyglucose (FDG)-positron emission tomography (PET) metabolism and digital pathology in patients with logopenic progressive aphasia (LPA) and pathologic diagnosis of diffuse Lewy body disease (DLBD) and compare to patients with LPA with other pathologies, as well as patients with classical features of probable dementia with Lewy bodies (pDLB).

METHODS

This is a clinicopathologic case-control study of 45 patients, including 20 prospectively recruited patients with LPA among whom 6 were diagnosed with LPA-DLBD. We analyzed clinical features and compared FDG-PET metabolism in LPA-DLBD to an independent group of patients with clinical pDLB and regional α-synuclein burden on digital pathology to a second independent group of autopsied patients with DLBD pathology and antemortem pDLB (DLB-DLBD).

RESULTS

All patients with LPA-DLBD were men. Neurological, speech, and neuropsychological characteristics were similar across LPA-DLBD, LPA-Alzheimer's disease (LPA-AD), and LPA-frontotemporal lobar degeneration (LPA-FTLD). Genetic screening of AD, DLBD, and FTLD linked genes were negative with the exception of APOE ε4 allele present in 83% of LPA-DLBD patients. Seventy-five percent of the patients with LPA-DLBD showed a parietal-dominant pattern of hy pometabolism; LPA-FTLD - temporal-dominant pattern, whereas LPA-AD showed heterogeneous patterns of hypometabolism. LPA-DLBD had more asymmetrical hypometabolism affecting frontal lobes, with relatively spared occipital lobe in the nondominantly affected hemisphere, compared to pDLB. LPA-DLBD had minimal atrophy on gross brain examination, higher cortical Lewy body counts, and higher α-synuclein burden in the middle frontal and inferior parietal cortices compared to DLB-DLBD.

INTERPRETATION

Whereas AD is the most frequent underlying pathology of LPA, DLBD can also be present and may contribute to the LPA phenotype possibly due to α-synuclein-associated functional impairment of the dominant parietal lobe. ANN NEUROL 2021;89:520-533.

"Semantic variant primary progressive aphasia" due to comorbidity of Lewy body disease and a previous cerebral venous infarction in the left anterior temporal lobe: A case report

Primary progressive aphasia (PPA) is a neurological syndrome characterized by progressive language impairment. Various neurodegenerative disorders cause PPA. Dementia with Lewy bodies (DLB) is one known cause of PPA, and little is known about this association. Almost all published cases of PPA associated with DLB are the logopenic variant of PPA. Here, we describe the novel case of a patient with DLB presenting clinical features of the semantic variant PPA (svPPA). A 75-year-old woman was referred to our hospital with a 2-year history of progressive anomia and amnesia. Two months before admission, she had been experiencing visual hallucinations, and at the age of 60 years, she had venous infarction in the left temporal lobe, which she recovered from without any residual symptoms. Upon admission to our hospital, she displayed anomia, impaired single-word comprehension, and surface dyslexia with preserved repetition and speech production. These symptoms met the criteria for the diagnosis of svPPA. ¹²³I-ioflupane single-photon emission computed tomography and ¹²³I-meta-iodobenzylguanidine myocardial scintigraphy indicated DLB. Thus, she was administered donepezil, and this dramatically improved her symptoms. We hypothesize that the combination of DLB with the previous asymptomatic venous thrombosis in the left temporal lobe may have contributed to the “svPPA” in this patient. In conclusion, we show that PPA associated with DLB could be treated with donepezil, and we suggest that donepezil should be pursued as a treatment option for PPA.

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Primary progressive aphasia is characterized by progressive language impairment.

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We report a case of primary progressive aphasia and dementia with Lewy bodies.

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MRI showed a previously found asymptomatic lesion in the left temporal lobe.

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A cholinesterase inhibitor improved cognitive functions, including language.

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Comorbidity disrupted the recovery of temporal lobe function and impaired language.

Primary Progressive Aphasia: Toward a Pathophysiological Synthesis

PURPOSE OF REVIEW

The term primary progressive aphasia (PPA) refers to a diverse group of dementias that present with prominent and early problems with speech and language. They present considerable challenges to clinicians and researchers.

RECENT FINDINGS

Here, we review critical issues around diagnosis of the three major PPA variants (semantic variant PPA, nonfluent/agrammatic variant PPA, logopenic variant PPA), as well as considering 'fragmentary' syndromes. We next consider issues around assessing disease stage, before discussing physiological phenotyping of proteinopathies across the PPA spectrum. We also review evidence for core central auditory impairments in PPA, outline critical challenges associated with treatment, discuss pathophysiological features of each major PPA variant, and conclude with thoughts on key challenges that remain to be addressed. New findings elucidating the pathophysiology of PPA represent a major step forward in our understanding of these diseases, with implications for diagnosis, care, management, and therapies.