Publications by authors named "Hugo Botha"

Background: Mayo Test Drive (MTD): Mayo Test Development through Rapid Iteration, Validation and Expansion, is a web-based remote cognitive assessment platform for self-administered neuropsychological measures with previously demonstrated validity and reliability. We examined the usability of MTD and hypothesized that completion rates would be greater than 90%. We explored whether completion and participation rates differed by cognitive status and demographic factors.

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Introduction: Apraxia of speech (AOS) is a motor speech disorder characterized by sound distortions, substitutions, deletions, and additions; slow speech rate; abnormal prosody; and/or segmentation between words and syllables. AOS can result from neurodegeneration, in which case it can be accompanied by the primary agrammatic aphasia (PAA), which when presenting together are called AOS+PAA. AOS can also be the sole manifestation of neurodegeneration, termed primary progressive AOS (PPAOS).

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Nerve conduction F-wave studies contain critical information about subclinical motor dysfunction which may be used to diagnose patients with amyotrophic lateral sclerosis (ALS). However, F-wave responses are highly variable in morphology, making waveform interpretation challenging. Artificial Intelligence techniques can extract time-frequency features to provide new insights into ALS diagnosis and prognosis.

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Importance: Although 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established cross-sectional biomarker of brain metabolism in dementia with Lewy bodies (DLB), the longitudinal change in FDG-PET has not been characterized.

Objective: To investigate longitudinal FDG-PET in prodromal DLB and DLB, including a subsample with autopsy data, and report estimated sample sizes for a hypothetical clinical trial in DLB.

Design, Setting, And Participants: Longitudinal case-control study with mean (SD) follow-up of 3.

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Background And Purpose: In idiopathic normal pressure hydrocephalus (iNPH) patients, cerebrospinal fluid (CSF) flow is typically evaluated with a cardiac-gated two-dimensional (2D) phase-contrast (PC) MRI through the cerebral aqueduct. This approach is limited by the evaluation of a single location and does not account for respiration effects on flow. In this study, we quantified the cardiac and respiratory contributions to CSF movement at multiple intracranial locations using a real-time 2D PC-MRI and evaluated the diagnostic value of CSF dynamics biomarkers in classifying iNPH patients.

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Background And Purpose: Idiopathic normal pressure hydrocephalus (iNPH) is a cerebrospinal fluid (CSF) dynamics disorder as evidenced by the delayed ascent of radiotracers over the cerebral convexity on radionuclide cisternography. However, the exact mechanism causing this disruption remains unclear. Elucidating the pathophysiology of iNPH is crucial, as it is a treatable cause of dementia.

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Objectives: To describe a case of spinocerebellar ataxia presenting with progressive apraxia of speech (AOS).

Methods: A 54-year-old man with progressive speech changes was seen clinically and referred to our observational research program on degenerative speech and language disorders. He underwent detailed speech-language and neurologic assessments and multimodal neuroimaging studies.

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Article Synopsis
  • - The study investigates isolated REM sleep behavior disorder (iRBD) and its links to neurodegenerative diseases, focusing on gender differences and younger adults, which are less explored compared to older males.
  • - Researchers followed 372 participants (186 women and 186 men with iRBD), finding that women were diagnosed at a younger age than men and that over 12% converted to a neurodegenerative disorder within roughly 6 years.
  • - Key findings indicate that older age at diagnosis is a significant factor for phenoconversion risk, with lower risk observed in those using antidepressants or having chronic pain, while higher risk was noted in individuals with vascular issues.
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There are recognized neuroimaging regions of interest in typical Alzheimer's disease which have been used to track disease progression and aid prognostication. However, there is a need for validated baseline imaging markers to predict clinical decline in atypical Alzheimer's Disease. We aimed to address this need by producing models from baseline imaging features using penalized regression and evaluating their predictive performance on various clinical measures.

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Introduction: Transcribing disordered speech can be useful when diagnosing motor speech disorders such as primary progressive apraxia of speech (PPAOS), who have sound additions, deletions, and substitutions, or distortions and/or slow, segmented speech. Since transcribing speech can be a laborious process and requires an experienced listener, using automatic speech recognition (ASR) systems for diagnosis and treatment monitoring is appealing. This study evaluated the efficacy of a readily available ASR system (wav2vec 2.

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Background: A definitive diagnosis of progressive supranuclear palsy (PSP) can only be established through neuropathological evaluations where four cardinal tau lesions are identified. Relationships between regional tau burden and disease duration/age at death is unclear.

Objective: To investigate relationships between tau burden in different brain regions and disease duration and age at death in PSP and determine whether association are influenced by PSP subtype (subcortical/cortical) or co-pathologies.

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Article Synopsis
  • Electrophysiologic changes in neurodegenerative disorders like Alzheimer's and Lewy Body disease can be identified using EEG, providing insight into disease severity.
  • Traditional EEG analysis is limited by biases from preset feature selection; this study uses a data-driven tensor decomposition method to extract key EEG activity features during resting states.
  • By analyzing data from over 11,000 patients, the researchers developed an algorithm to differentiate cognitive impairment and dementia types based on identifiable EEG patterns, which showed correlations with mental status and biomarkers.
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  • - Nonverbal oral apraxia (NVOA) is a condition affecting the ability to perform voluntary oromotor movements without physical weakness; this study aimed to explore its relationship with various neurodegenerative diseases and their clinical or neuroimaging traits.
  • - The study analyzed 104 autopsy-confirmed patients, finding that 60.6% developed NVOA, primarily in individuals diagnosed with primary progressive apraxia of speech and its variants; those with NVOA showed specific brain atrophy patterns, particularly in the left frontal cortex.
  • - Pathologies linked to NVOA included progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD); importantly, a significant number of patients exhibited
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Digital quantification of gait can be used to measure aging- and disease-related decline in mobility. Gait performance also predicts prognosis, disease progression, and response to therapies. Most gait analysis systems require large amounts of space, resources, and expertise to implement and are not widely accessible.

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Article Synopsis
  • Progressive supranuclear palsy (PSP) is a complex neurodegenerative disease characterized by diverse clinical symptoms, and this study explores patterns of brain atrophy and metabolic changes associated with different PSP subtypes.
  • A total of 111 PSP patients were analyzed using both MRI and FDG-PET scans to identify how these imaging techniques correlate with specific clinical features like postural instability and ocular motor issues.
  • Results indicate that imaging techniques are more effective at identifying the presence of symptoms rather than their severity, with FDG-PET being particularly good at detecting cortical abnormalities and MRI better at identifying subcortical issues, highlighting distinct neuroanatomical predictors for various symptoms.
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Predominant limbic degeneration has been associated with various underlying aetiologies and an older age, predominant impairment of episodic memory and slow clinical progression. However, the neurological syndrome associated with predominant limbic degeneration is not defined. This endeavour is critical to distinguish such a syndrome from those originating from neocortical degeneration, which may differ in underlying aetiology, disease course and therapeutic needs.

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Primary progressive aphasia (PPA) variants present with distinct disruptions in speech-language functions with little known about the interplay between affected and spared regions within the speech-language network and their interaction with other functional networks. The Neurodegenerative Research Group, Mayo Clinic, recruited 123 patients with PPA (55 logopenic (lvPPA), 44 non-fluent (nfvPPA) and 24 semantic (svPPA)) who were matched to 60 healthy controls. We investigated functional connectivity disruptions between regions within the left-speech-language network (Broca, Wernicke, anterior middle temporal gyrus (aMTG), supplementary motor area (SMA), planum temporale (PT) and parietal operculum (PO)), and disruptions to other networks (visual association, dorsal-attention, frontoparietal and default mode networks (DMN)).

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Objective: To evaluate the performance of Alzheimer disease (AD) cerebrospinal fluid (CSF) biomarkers in a tertiary neurology clinic setting with high frequency of non-AD cases, including normal pressure hydrocephalus (NPH).

Methods: There were 534 patients who underwent AD CSF biomarkers (Roche Elecsys Aβ42, p-Tau181, total-Tau) from April 1, 2020, through April 23, 2021. A behavioral neurologist blinded to CSF results assigned a clinical diagnosis retrospectively on the basis of consensus criteria, and a neuroradiologist blinded to the diagnosis and CSF studies graded brain magnetic resonance images for indicators of CSF dynamics disorders.

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Background: Large curated data sets are required to leverage speech-based tools in health care. These are costly to produce, resulting in increased interest in data sharing. As speech can potentially identify speakers (ie, voiceprints), sharing recordings raises privacy concerns.

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Purpose: We describe the communication challenges of four patients with a neurodegenerative disorder consistent with behavioral variant frontotemporal dementia (bvFTD), characterized by early behavioral and personality changes. By describing their clinical profiles, we identify common barriers to functional communication in this population and provide recommendations for how speech-language pathologists (SLPs) might contribute to minimizing them.

Method: Four patients with bvFTD were selected from a cohort of patients with progressive communication impairments.

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Article Synopsis
  • Some patients accidentally say "yes" when they mean "no," and this can happen with gestures too.
  • This problem is linked to certain brain conditions, but scientists don’t fully understand why it happens or when it shows up.
  • A study of patients with speech issues found that those who had this mix-up did worse on tests of brain function and had less brain activity in specific areas related to controlling responses.
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Progressive apraxia of speech (PAOS) is a 4R tauopathy characterized by difficulties with motor speech planning. Neurodegeneration in PAOS targets the premotor cortex, particularly the supplementary motor area (SMA), with degeneration of white matter (WM) tracts connecting premotor and motor cortices and Broca's area observed on diffusion tensor imaging (DTI). We aimed to assess flortaucipir uptake across speech-language-related WM tracts identified using DTI tractography in PAOS.

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Article Synopsis
  • The study examines early deposition patterns of amyloid-β (Aβ) plaques in the neocortex of individuals, using Pittsburgh compound B (PiB) PET scans from 1,088 participants.
  • Researchers found that early Aβ loading primarily occurs in the temporal, cingulate, and occipital regions, with similar patterns observed in individuals with and without the apolipoprotein ε4 gene.
  • The analysis identified distinct clusters of early amyloid deposition, which could be important for improving diagnostic methods and understanding how Alzheimer’s disease develops.
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Progressive supranuclear palsy is a neurodegenerative disease characterized by the deposition of four-repeat tau in neuronal and glial lesions in the brainstem, cerebellar, subcortical and cortical brain regions. There are varying clinical presentations of progressive supranuclear palsy with different neuroimaging signatures, presumed to be due to different topographical distributions and burden of tau. The classic Richardson syndrome presentation is considered a subcortical variant, whilst progressive supranuclear palsy with predominant speech and language impairment is considered a cortical variant, although the pathological underpinnings of these variants are unclear.

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Article Synopsis
  • - The study investigated the safety of ventriculoperitoneal shunt placement in older patients with idiopathic normal pressure hydrocephalus (iNPH) who were either on anticoagulation therapy or not.
  • - Out of 234 patients reviewed, those on anticoagulants experienced a higher incidence of tract hemorrhage post-surgery (11.1% vs. 2.5%), but rates of other hemorrhagic complications were similar across both groups.
  • - The findings highlight the common use of anticoagulants in the iNPH patient population and suggest careful monitoring may be necessary for those undergoing shunt placement.
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