Clinical phenotypes of progressive aphasia

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.

OUP accepted manuscript

Primary progressive aphasia, a neurodegenerative syndrome, presents mainly with language impairment. Both semantic and logopenic variants are fluent variants of primary progressive aphasia. Before the research criteria of primary progressive aphasia were proposed, progressive fluent aphasias, such as progressive anomic aphasia, transcortical sensory aphasia and Wernicke’s aphasia, were reported as classical progressive fluent aphasias seen in Alzheimer’s disease. However, since the research criteria of primary progressive aphasia were established, classical fluent variants (other than semantic and logopenic variants) have been neglected and have not been included in the current classification of primary progressive aphasia. This study aimed to determine whether unclassified fluent variants (other than semantic and logopenic variants) can be manifestations of primary progressive aphasia. This study also reconfirmed the characteristics of classical progressive fluent aphasia, such as progressive anomic aphasia, progressive transcortical sensory aphasia and progressive Wernicke’s aphasia as unclassified fluent variants of primary progressive aphasia, using comparison with the current model of primary progressive aphasia. Twelve consecutive patients with an unclassified fluent variant other than semantic or logopenic variant underwent language, neurological, neuropsychological and neuroimaging (MRI and single-photon emission computed tomography) testing. Based on comprehensive language tests, we redefined the diagnoses as primary progressive anomic aphasia (n = 8), primary progressive transcortical sensory aphasia (n = 3) and primary progressive Wernicke’s aphasia (n = 1). Anomic aphasia was characterized by anomia but preserved repetition and comprehension; transcortical sensory aphasia by relatively preserved repetition but poor word comprehension; and Wernicke’s aphasia by poor repetition and word comprehension. In patients with anomic aphasia, voxel-based morphometry of MRI data revealed cortical atrophy, which was most prominent in the temporoparietal lobes, with no obvious lateralization; in two-thirds of patients with transcortical sensory aphasia and in one patient with Wernicke’s aphasia, it revealed atrophy, predominantly in the left temporoparietal lobe. Statistical analysis of single-photon emission computed tomography using three-dimensional stereotactic surface projections revealed patterns of left-sided hypoperfusion in the majority of patients. The temporal and parietal lobes were involved in all cases; the degree of hypoperfusion was higher in patients with transcortical sensory aphasia or Wernicke’s aphasia than in patients with anomic aphasia. The present study demonstrated the clinical and imaging features of 12 patients with an unclassified fluent variant of primary progressive aphasia, which we redefined as primary progressive anomic aphasia, primary progressive transcortical sensory aphasia and primary progressive Wernicke’s aphasia. Classical fluent variants other than semantic and logopenic variants can be found in primary progressive aphasia.

First Symptoms of Primary Progressive Aphasia and Alzheimer's Disease in Brazilian Individuals

Background: Primary Progressive Aphasia (PPA) is characterized by progressive language impairment due to focal degeneration of brain areas related to linguistic processing. The detection and differential diagnosis of PPA can be difficult with clinical features that may overlap with features of other neurological conditions, such as Alzheimer's disease (AD). The scientific production on PPA in Latin American patients is still scarce. This study investigated the first symptoms in a Brazilian sample of patients with PPA in comparison with AD patients.

Method: We compared the first symptoms reported by caregivers of people with PPA (n = 20; semantic variant n = 8, non-fluent variant n = 7, logopenic variant n = 3, and unclassified cases n = 2) and AD (n = 16). Data were collected through the application of a structured questionnaire that was presented in an interview format to the caregiver who knew the patient best.

Results: Anomia, paraphasias and motor speech difficulties were the first symptoms capable of differentiating patients with PPA from those with AD, while memory was exclusive of AD. Among the PPA variants, anomia was the initial symptom associated with the semantic variant, while motor speech difficulties were associated with the non-fluent variant. The results are discussed considering the unique cultural and sociodemographic characteristics of this studied population.

Conclusion: This study demonstrated that some of the initial symptoms of PPA patients may be unique to clinical variants of PPA and of AD, and their investigation may be useful for the early and differential diagnosis of this population.

Primary Progressive Aphasia as a Prodromal State of Dementia With Lewy Bodies: A Case Report

Dementia with Lewy bodies (DLB) is the second most common form of dementia in the elderly, and various clinical symptoms, including olfactory dysfunction, dysautonomia, depression, and rapid eye movement sleep behavior disorders (RBD), occur in patients with the prodromal state of DLB. We herein describe a case of a 72-years-old right-handed woman who exhibited primary progressive aphasia (PPA) as a prodromal state of DLB and took cholinesterase inhibitors (donepezil). At 4.5 years after aphasia onset, she exhibited all the core clinical features of DLB, including visual hallucinations, fluctuating cognition, RBD, and Parkinsonism, as well as progressive language impairment. She showed reduced dopamine transporter (DAT) uptake (assessed by DAT single-photon emission computed tomography imaging) in the striatum and decreased cardiac uptake (determined by ¹²³I-metaiodobenzylguanidine myocardial scintigraphy), which are indicative biomarkers of DLB. Thus, this patient met all the criteria for probable DLB. Notably, the unique feature of this case was the presentation of PPA, which is seldom observed in typical DLB. Moreover, cholinergic enhancement (donepezil, 5 mg daily) improved her language function and global cognitive function, although mild aphasia remained. The findings provide valuable insights into the spectrum of the prodromal state of DLB and shed light on the development of the medication for PPA caused by cholinergic insufficiency.