Cortical neuroanatomical changes related to specific language impairments in primary progressive aphasia

Objective

Language function test-specific neural substrates in Korean patients with primary progressive aphasia (PPA) might differ from those in other causes of dementia and English-speaking PPA patients. We investigated the correlation between language performance tests and cortical thickness to determine neural substrates in Korean patients with PPA.

Materials and methods

Ninety-six patients with PPA were recruited from the memory clinic. To acquire neural substrates, we performed linear regression using the scores of each language test as a predictor, cortical thickness as an outcome and age, sex, years of education, and intracranial volume as confounders.

Results

Poor performance in each language function test was associated with lower cortical thickness in specific cortical regions: (1) object naming and the bilateral anterior to mid-portion of the lateral temporal and basal temporal regions; (2) semantic generative naming and the bilateral anterior to mid-portion of the lateral temporal and basal temporal regions; (3) phonemic generative naming and the left prefrontal and inferior parietal regions; and (4) comprehension and the left posterior portion of the superior and middle temporal regions. In particular, the neural substrates of the semantic generative naming test in PPA patients, left anterior to mid-portion of the lateral and basal temporal regions, quite differed from those in patients with other causes of dementia.

Conclusion

Our findings provide a better understanding of the different pathomechanisms for language impairments among PPA patients from those with other causes of dementia.

Detection and differentiation of ataxic and hypokinetic dysarthria in cerebellar ataxia and parkinsonian disorders via wave splitting and integrating neural networks

Dysarthria may present during the natural course of many degenerative neurological conditions. Hypokinetic and ataxic dysarthria are common in movement disorders and represent the underlying neuropathology. We developed an artificial intelligence (AI) model to distinguish ataxic dysarthria and hypokinetic dysarthria from normal speech and differentiate ataxic and hypokinetic speech in parkinsonian diseases and cerebellar ataxia. We screened 804 perceptual speech analyses performed in the Samsung Medical Center Neurology Department between January 2017 and December 2020. The data of patients diagnosed with parkinsonian disorders or cerebellar ataxia were included. Two speech tasks (numbering from 1 to 50 and reading nine sentences) were analyzed. We adopted convolutional neural networks and developed a patch-wise wave splitting and integrating AI system for audio classification (PWSI-AI-AC) to differentiate between ataxic and hypokinetic speech. Of the 395 speech recordings for the reading task, 76, 112, and 207 were from normal, ataxic dysarthria, and hypokinetic dysarthria subjects, respectively. Of the 409 recordings of the numbering task, 82, 111, and 216 were from normal, ataxic dysarthria, and hypokinetic dysarthria subjects, respectively. The reading and numbering task recordings were classified with 5-fold cross-validation using PWSI-AI-AC as follows: hypokinetic dysarthria vs. others (area under the curve: 0.92 ± 0.01 and 0.92 ± 0.02), ataxia vs. others (0.93 ± 0.04 and 0.89 ± 0.02), hypokinetic dysarthria vs. ataxia (0.96 ± 0.02 and 0.95 ± 0.01), hypokinetic dysarthria vs. none (0.86 ± 0.03 and 0.87 ± 0.05), and ataxia vs. none (0.87 ± 0.07 and 0.87 ± 0.09), respectively. PWSI-AI-AC showed reliable performance in differentiating ataxic and hypokinetic dysarthria and effectively augmented data to classify the types even with limited training samples. The proposed fully automatic AI system outperforms neurology residents. Our model can provide effective guidelines for screening related diseases and differential diagnosis of neurodegenerative diseases.

Two cases of non-fluent variant primary progressive aphasia with different pathological diagnoses

Non-fluent variant primary progressive aphasia (nfvPPA), a subtype of frontotemporal lobar dementia syndrome, has been proven to have various pathological diagnoses. A 63-year-old woman and 71-year-old man separately visited our clinic for language dysfunction. Both patients showed non-fluent speech. The female patient showed personality change accompanied by language dysfunction, while the male patient had parkinsonian symptoms such as bradykinesia and cogwheel rigidity. Both patients were clinically diagnosed with nfvPPA. Several years after the first visit, the patients died, and a brain autopsy was performed. On postmortem examination, the female patient was pathologically diagnosed with Pick’s disease, while the male patient was diagnosed with progressive supranuclear palsy. Our report suggests that nfvPPA patients might show distinct clinical features depending on underlying pathologies.

Clinical Characteristic in Primary Progressive Aphasia in Relation to Alzheimer's Disease Biomarkers

BACKGROUND

Primary progressive aphasia (PPA) is associated with amyloid-β (Aβ) pathology. However, clinical feature of PPA based on Aβ positivity remains unclear.

OBJECTIVE

We aimed to assess the prevalence of Aβ positivity in patients with PPA and compare the clinical characteristics of patients with Aβ-positive (A+) and Aβ-negative (A-) PPA. Further, we applied Aβ and tau classification system (AT system) in patients with PPA for whom additional information of in vivo tau biomarker was available.

METHODS

We recruited 110 patients with PPA (41 semantic [svPPA], 27 non-fluent [nfvPPA], 32 logopenic [lvPPA], and 10 unclassified [ucPPA]) who underwent Aβ-PET imaging at multi centers. The extent of language impairment and cortical atrophy were compared between the A+ and A-PPA subgroups using general linear models.

RESULTS

The prevalence of Aβ positivity was highest in patients with lvPPA (81.3%), followed by ucPPA (60.0%), nfvPPA (18.5%), and svPPA (9.8%). The A+ PPA subgroup manifested cortical atrophy mainly in the left superior temporal/inferior parietal regions and had lower repetition scores compared to the A-PPA subgroup. Further, we observed that more than 90% (13/14) of the patients with A+ PPA had tau deposition.

CONCLUSION

Our findings will help clinicians understand the patterns of language impairment and cortical atrophy in patients with PPA based on Aβ deposition. Considering that most of the A+ PPA patents are tau positive, understanding the influence of Alzheimer's disease biomarkers on PPA might provide an opportunity for these patients to participate in clinical trials aimed for treating atypical Alzheimer's disease.

Differences in neuroimaging features of early- versus late-onset nonfluent/agrammatic primary progressive aphasia

This study investigated distinct neuroimaging features measured by cortical thickness and subcortical structural shape abnormality in early-onset (EO, onset age <65 years) and late-onset (LO, onset age ≥65 years) nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA) patients. Cortical thickness and subcortical structural shape analyses were performed using a surface-based method from 38 patients with nfvPPA and 76 cognitively normal individuals. To minimize the effects of physiological aging, we used W-scores in comparisons between the groups. The EO-nfvPPA group exhibited more extensive cortical thickness reductions predominantly in the left perisylvian, lateral and medial prefrontal, temporal, posterior cingulate, and precuneus regions than the LO-nfvPPA group. The EO-nfvPPA group also exhibited significantly greater subcortical structural shape abnormality than the LO-nfvPPA group, mainly in the left striatum, hippocampus, and amygdala. Our findings suggested that there were differences in neuroimaging features between these groups by the age of symptom onset, which might be explained by underlying heterogeneous neuropathological differences or the age-related brain reserve hypothesis.

Relationships between [¹⁸F]-THK5351 Retention and Language Functions in Primary Progressive Aphasia

BACKGROUND AND PURPOSE

There are three distinct subtypes of primary progressive aphasia (PPA): the nonfluent/agrammatic variant (nfvPPA), the semantic variant (svPPA), and the logopenic variant (lvPPA). We sought to characterize the pattern of [¹⁸F]-THK5351 retention across all three subtypes and determine the topography of [¹⁸F]-THK5351 retention correlated with each neurolinguistic score.

METHODS

We enrolled 50 participants, comprising 13 PPA patients (3 nfvPPA, 5 svPPA, and 5 lvPPA) and 37 subjects with normal cognition (NC) who underwent 3.0-tesla magnetic resonance imaging, [¹⁸F]-THK5351 positron-emission tomography scans, and detailed neuropsychological tests. The PPA patients additionally participated in extensive neurolinguistic tests. Voxel-wise and region-of-interest-based analyses were performed to analyze [¹⁸F]-THK5351 retention.

RESULTS

The nfvPPA patients exhibited higher [¹⁸F]-THK5351 retention in the the left inferior frontal and precentral gyri. In svPPA patients, [¹⁸F]-THK5351 retention was elevated in the anteroinferior and lateral temporal cortices compared to the NC group (left>right). The lvPPA patients exhibited predominant [¹⁸F]-THK5351 retention in the inferior parietal, lateral temporal, and dorsolateral prefrontal cortices, and the precuneus (left>right). [¹⁸F]-THK5351 retention in the left inferior frontal area was associated with lower fluency scores. Comprehension was correlated with [¹⁸F]-THK5351 retention in the left temporal cortices. Repetition was associated with [¹⁸F]-THK5351 retention in the left inferior parietal and posterior temporal areas, while naming difficulty was correlated with retention in the left fusiform and temporal cortices.

CONCLUSIONS

The pattern of [¹⁸F]-THK5351 retention was well matched with clinical and radiological findings for each PPA subtype, in agreement with the anatomical and functional location of each language domain.

Differences in early speech patterns between Parkinson variant of multiple system atrophy and Parkinson's disease

In Parkinson variant of multiple system atrophy (MSA-P), patterns of early speech impairment and their distinguishing features from Parkinson's disease (PD) require further exploration. Here, we compared speech data among patients with early-stage MSA-P, PD, and healthy subjects using quantitative acoustic and perceptual analyses. Variables were analyzed for men and women in view of gender-specific features of speech. Acoustic analysis revealed that male patients with MSA-P exhibited more profound speech abnormalities than those with PD, regarding increased voice pitch, prolonged pause time, and reduced speech rate. This might be due to widespread pathology of MSA-P in nigrostriatal or extra-striatal structures related to speech production. Although several perceptual measures were mildly impaired in MSA-P and PD patients, none of these parameters showed a significant difference between patient groups. Detailed speech analysis using acoustic measures may help distinguish between MSA-P and PD early in the disease process.

Structural brain changes after traditional and robot-assisted multi-domain cognitive training in community-dwelling healthy elderly

The purpose of this study was to investigate if multi-domain cognitive training, especially robot-assisted training, alters cortical thickness in the brains of elderly participants. A controlled trial was conducted with 85 volunteers without cognitive impairment who were 60 years old or older. Participants were first randomized into two groups. One group consisted of 48 participants who would receive cognitive training and 37 who would not receive training. The cognitive training group was randomly divided into two groups, 24 who received traditional cognitive training and 24 who received robot-assisted cognitive training. The training for both groups consisted of daily 90-min-session, five days a week for a total of 12 weeks. The primary outcome was the changes in cortical thickness. When compared to the control group, both groups who underwent cognitive training demonstrated attenuation of age related cortical thinning in the frontotemporal association cortices. When the robot and the traditional interventions were directly compared, the robot group showed less cortical thinning in the anterior cingulate cortices. Our results suggest that cognitive training can mitigate age-associated structural brain changes in the elderly.

Is phonological-lexical representation preserved in moderate stage Alzheimer disease? Evidence from the efficacy of Korean syllabic cues

Patients with Alzheimer disease (AD) usually experience naming difficulty due to storage and access problems in phonological-lexical representation. Investigating naming response patterns followed by cueing may help us to understand the underlying mechanism of naming deficits in AD. A total of 221 patients with mild cognitive impairment and AD [Clinical Dementia Rating (CDR) 0.5, 1, 2] were included as subjects. Sixty items of the Korean version of the Boston Naming Test were given, and upon failure, semantic/syllabic cues were verbally presented. From the results, even in the CDR 2 group, which is considered to be a moderate stage of AD, syllabic cues significantly facilitated correct responses. Our findings are in contrast with previous studies conducted with English-speaking patients, which reported that phonological-lexical representation may have been disrupted in the moderate stage of AD, and that none of the cues facilitated correct word retrieval. The difference may be ascribed to the fact that direct access to the phonological-lexical representation via syllabic cues was possible in the confrontation naming task performed by the Korean patients. It can be concluded that phonological-lexical representation in moderate stage Korean AD might be partially preserved because syllabic cues in AD patients were effective in facilitating target words.

Agraphia caused by acute right parietal infarction

Injury in the dominant language hemisphere typically leads to agraphia, however we report a patient with agraphia after injury to the right angular gyrus. A 71-year-old Korean woman presented with the complaint of an inability to write for the last 7 days. The patient had been illiterate for most of her life, but had started learning to write Hangul, the Korean alphabet, at a welfare center 3 years ago. On language screening she was unable to write although she could read, and other language functions showed no abnormalities. Brain MRI showed acute infarction in the right angular gyrus. Her writing patterns displayed features of surface agraphia, indicative of phoneme-to-grapheme conversion with phonetic writing of targets. Additionally, she manifested visual errors. A functional MRI indicated that her left hemisphere was language dominant. This patient experienced agraphia resulting from pure impairment of visuo-constructive function after acute infarction in the right angular gyrus.

Postmorbid learning of saxophone playing in a patient with frontotemporal dementia

Some patients with frontotemporal dementia (FTD) show an artistic enhancement of musical abilities. However, no patients with FTD, to date, have been reported to be able to learn how to play a musical instrument after disease onset. Herein we describe a patient (J. K.) who had never played any musical instruments premorbidly, but who learned to play the saxophone after being diagnosed with a behavioral variant of FTD. He mastered a repertoire that consisted of 10 pieces of Korean folk songs over a period of three years. Furthermore, his saxophone skills were high enough to outperform other students in his class.

Amyloid deposition in early onset versus late onset Alzheimer's disease

BACKGROUND

Patients with early-onset Alzheimer's disease (EOAD) may differ from those with late-onset Alzheimer's disease (LOAD) in cognitive impairment profiles and clinical course. Postmortem studies also reported that EOAD has a greater pathologic burden than LOAD. We examined the effects of age at onset on the burden and distribution of amyloid plaques in patients with AD, using a statistical parametric mapping (SPM) and regions of interest (ROIs) analyses of the Pittsburgh compound B (PiB)-PET.

METHODS

We initially recruited 72 patients with AD who had completed the [11C] PiB-PET scan, but four patients were excluded due to familial AD or incomplete MRI data. Of the 68 patients, 61 were classified as PiB-positive (PiB+) and seven as PiB-negative (PiB-) using the measured global PiB uptake ratio values. Of the 61 patients with PiB+ AD, in order to maximize the effect of onset age, we excluded 20 patients in their 60 s. Thus among the remaining 41 patients, the amyloid deposition of only 17 patients with EOAD (age onset <60 years) and 24 patients with LOAD (onset age ≥70 years) were compared.

RESULTS

There were no significant differences in the global mean PiB index between EOAD and LOAD patients, whereas SPM and ROIs analyses showed that those with EOAD retained higher levels of PiB in the bilateral basal ganglia, bilateral thalamus, left superior temporal cortex, and left cuneus compared to those with LOAD.

CONCLUSION

Our findings demonstrated that EOAD patients differed from those with LOAD in the topography of amyloid deposition, which may partly account for the findings from previous studies that extrapyramidal symptoms and frontal dysfunction are more common in EOAD than in LOAD patients.

Pure word deafness in a patient with early-onset Alzheimer's disease: an unusual presentation

BACKGROUND AND PURPOSE

The occurrence of PWD in neurodegenerative disease is very rare, and this is the first report of it being related to early-onset AD. We describe a patient with early-onset Alzheimer's disease (AD) who presented with pure word deafness (PWD).

CASE REPORT

The patient had experienced PWD for 2 years, followed by other cognitive deficits suggestive of parietotemporal dysfunction. Brain imaging including (18)FDG-PET and [(11)C] PIB-PET supported the diagnosis of AD.

CONCLUSIONS

Our case highlights the clinical variability that characterizes early-onset AD.

Seoul Neuropsychological Screening Battery-dementia version (SNSB-D): a useful tool for assessing and monitoring cognitive impairments in dementia patients

The Seoul Neuropsychological Screening Battery (SNSB) is one of the standardized neuropsychological test batteries widely used in Korea. However, it may be a bit too lengthy for patients with decreased attention span; and it does not provide the score of global cognitive function (GCF), which is useful for monitoring patients longitudinally. We sought to validate a dementia version of SNSB (SNSB-D) that was shorter than the original SNSB and contained only scorable tests with a GCF score of 300. We administered SNSB-D to patients with mild cognitive impairment (MCI) (n=43) and Alzheimer's disease (AD) (n=93), and normal controls (NC) (n=77). MCI and AD groups had GCF scores significantly different from NC group, and GCF scores were able to distinguish patients with Clinical Dementia Rating of 0.5 and 1. Test-retest reliability was high, with a correlation coefficient of 0.918 for AD, 0.999 for MCI, and 0.960 for NC. The GCF score significantly correlated with the Mini-Mental State Examination (MMSE). Through ROC-curve analysis, GCF scores were found to yield more accurate diagnoses than the MMSE. The SNSB-D is a valid, reliable tool for assessing the overall cognitive function, and can be used to monitor cognitive changes in patients with dementia.

Hanja (Ideogram) alexia and agraphia in patients with semantic dementia

Posterior fusiform gyrus (BA 37) is responsible for Hanja (ideogram) alexia in stroke patients. Patients with semantic dementia (SD) have lesions in the basal temporal area. The close proximity in these two lesions and the fact that reading ideograms requires holistic processing as is necessary in recognition of objects, suggests a possibility that ideogram alexia/agraphia may occur in patients with SD. We established and carried out Hanja and Hangul (phonogram) reading/writing tasks on six SD patients and nine Alzheimer's disease (AD) patients as control to see if these two patient groups show dissociation in the two sets of tests. SPM analysis was performed on the SD patients' PET images to look for any dysfunctions in the posterior fusiform gyrus. The SD patients manifested Hanja alexia/agraphia whereas Hangul reading/writing ability was relatively preserved. There were group differences between SD and AD in the Hanja tasks but not in the Hangul tasks. The SPM analysis revealed no hypometabolism in the posterior fusiform gyrus, but only in the middle and the anterior part of the temporal gyrus. Dysfunction in the middle temporal gyrus (BA 21) may have disrupted the temporal lobe connections preventing the function of the posterior fusiform gyrus.

Secular trends in adult male smoking from 1992 to 2006 in South Korea: age-specific changes with evolving tobacco-control policies

OBJECTIVES

For years, South Korea has had one of the highest levels of tobacco use among males in the world, but a steady decline has been observed recently. This study examined how the smoking behaviour of male adults changed with age after the implementation of national tobacco control policies in 1995.

STUDY DESIGN

Repeated cross-sectional study using a national survey.

METHODS

Data were obtained from the 1992, 1995, 1999, 2003 and 2006 results of a repeated cross-sectional survey, the Social Statistics Survey. The smoking status of adult men was compared before (1992 and 1995 surveys) and after (1999, 2003 and 2006 surveys) the implementation of government-directed tobacco control policies using graphical methods and logistic regression analysis.

RESULTS

After the implementation of tobacco control policies, the percentage of current male smokers decreased while the percentage of former smokers increased markedly. Smoking prevalence among older men (aged 50 years or more) reduced initially, and this decline was more pronounced after the tobacco control policies were implemented. Smoking prevalence in younger men (aged 30-49 years) declined in 2003 when more comprehensive tobacco control policies were implemented.

CONCLUSIONS

This study suggests that comprehensive tobacco control policies in South Korea reduced smoking prevalence among males, initially among older men and later among both older men and younger men.

Semantic dementia combined with motor neuron disease

Up to 20% of patients with behavioural variants of frontotemporal dementia (FTD) also have motor neuron disease (MND); conversely, this comorbidity is rare in patients with language variants of FTD. A few patients have been reported with semantic dementia (SD) combined with MND. However, these patients demonstrated the clinical features of MND in the advanced stage. We report a patient with SD who also demonstrated MND symptoms in an earlier stage of the disease. A 61-year-old man visited our memory disorder clinic as a result of language disturbance and dysarthria of 8 months duration and facial recognition impairment of 3 months duration. Neuropsychological tests revealed anomic aphasia, prosopagnosia, and decreased semantic fluency. A brain MRI revealed significant atrophies localized in both anterior temporal lobes with a greater prominence on the right side. Clinical examination and electrophysiological studies confirmed a diagnosis of MND 17 months after the onset of the disease.

Neglect dyslexia: frequency, association with other hemispatial neglects, and lesion localization

Patients with right hemisphere injury often omit or misread words on the left side of a page or the beginning letters of single words (neglect dyslexia). Our study involving a large sample of acute right hemisphere stroke investigated (1) the frequency of neglect dyslexia (ND), (2) the association between ND and other types of contralesional hemispatial neglect (CN), (3) the effect of visual field defect (VFD) on ND, and (4) the anatomical substrates for ND. Participants were 138 consecutive patients with right hemisphere stroke who underwent a neglect test battery including a test for ND. ND was considered present if the patient misread or omitted the left portion of the word in three or more of the 25 target words. CN was noted in 80/138 (58.0%) patients while ND was found in 31/138 (22.5%) patients. Of the 80 patients with CN, the frequency of neglect based on ND test was only 37.5% while the frequency of neglect based on other neglect tasks ranged from 51.3% to 86.3%. The severity of neglect was a significant predictor for ND. VFD was also a significant predictor for the occurrence of ND but this effect disappeared when the severity of neglect was controlled. Patients with CN had lesions in the superior and middle temporal gyri, inferior parietal lobule, and posterior insular cortex; patients with ND had additional lesions in the lingual and fusiform gyri. In summary, ND was dissociated from other types of neglect and was most often associated with severe neglect. VFD contributed to the occurrence of ND. ND resulted from lesions of temporoparietal junction areas (inferior parietal/superior temporal gyri) combined with those of lingual/fusiform gyri.

Influence of Moving Background on Line Bisection Performance in the Normal Elderly Versus Patients with Hemispatial Neglect

OBJECTIVE

Previous studies have shown that when healthy young participants bisect stationary lines on a moving background (MB) or optokinetic stimulation, they perceive the stationary line moving in the opposite direction of the MB (illusory motion [IM]), and they displace their bisection mark in the direction of the IM. This study attempted to learn whether IM also influences attentional biases of the healthy elderly and patients with hemispatial neglect.

DESIGN

In experiment 1, healthy elderly participants and patients with neglect bisected lines in conditions where IM was absent or present. To better understand the MB dichotomy between the healthy elderly and neglect patients, in experiment 2, participants' eye movements were recorded using an infrared eye tracker.

RESULTS

In experiment 1, healthy elderly participants' biases occurred in the opposite direction of MB when IM was present but in the same direction of MB when IM was absent. In contrast, neglect patients' biases occurred in the same direction of MB regardless of conditions. Eye movements reflect the spatial direction of attention. In experiment 2, the healthy elderly participants were able to selectively attend to the line, whereas neglect patients were impaired in that they fixated on the line.

CONCLUSIONS

These results suggest that the healthy elderly can selectively fixate on a line, and with MB, they perceive the stationary line moving, resulting in a bisection bias in the direction of the IM. In contrast, when there is an MB, the patients with neglect are impaired in that they fixate on the line. Thus, they do not perceive IM; instead, they are primarily influenced by the MB.

Subcutaneous hyalohyphomycosis due to Cephalotheca foveolata in an immunocompetent host

We report the first case of subcutaneous hyalohyphomycosis caused by the genus Cephalotheca, which has not been reported to cause human infection. A 67-year-old immunocompetent farmer presented with a 10-year history of verrucous erythematous plaques on the right foot dorsum, great toe, heel and sole. Histopathology of the lesions revealed chronic granulomatous inflammation with numerous nonpigmented fungal spores in the dermis. Cultures of biopsy specimens on Sabouraud's dextrose agar for 2 weeks developed into yellowish brown, velvety colonies that subsequently turned black after 8 weeks because of the production of black cleistothecia indicating the teleomorph. On the basis of mycological features, scanning electron microscopic morphology and molecular analysis data, a new species of Cephalotheca was identified and designated Cephalotheca foveolata. Because there was no response to the antifungal agents administered, the patient was successfully treated by surgical excision with skin graft.