John J Sidtis

John J Sidtis
Nathan Kline Institute · Geriatrics

Ph.D.

About

356
Publications
18,930
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10,282
Citations
Additional affiliations
February 2001 - present
Nathan Kline Institute
Position
  • Researcher

Publications

Publications (356)
Article
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Background Functional brain imaging has become the dominant approach to the study of brain-behavior relationships. Unfortunately, the behavior half of the equation has been relegated to second-class status when it is not ignored completely. Different approaches to connectivity, based on temporally correlated physiological events across the brain, h...
Article
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Recent studies have demonstrated that details of verbal material are retained in memory. Further, converging evidence points to a memory-enhancing effect of emotion such that memory for emotional events is stronger than memory for neutral events. Building upon this work, it appears likely that verbatim sentence forms will be remembered better when...
Article
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Background: Disordered speech production, dysarthria, is a common characteristic of the spinocerebellar ataxias (SCA). Although dysarthric features differ across SCAs, a previous analysis revealed that a combination of regional cerebral blood flow (rCBF) in the left inferior frontal region and the right caudate predicted syllable rate, a pattern r...
Article
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Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an effective treatment for Parkinson's disease (PD) but can have an adverse effect on speech. In normal speakers and in those with spinocerebellar ataxia, an inverse relationship between regional cerebral blood flow (rCBF) in the left inferior frontal (IFG) region and the ri...
Article
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The relationship between speech and singing in cerebral function is not fully understood. The effects of focal brain damage on pitch, timing, and rhythm in speech and singing were retrospectively investigated in two persons diagnosed with dysprosodic speech following cerebral vascular accidents; both were experienced singers. Participant 1 suffered...
Chapter
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To understand what the speaking brain tells us about functional imaging, it is important to realize what brains that cannot speak, that speak nonsense, or speak poorly tell us. In the century before positron emission and nuclear magnetic resonance were harnessed for neurobiological research, brain-behavior relationships were identified and studied...
Article
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Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an effective and widely used tool in the treatment of Parkinson's disease (PD). STN-DBS has varied effects on speech. Clinical speech ratings suggest worsening following STN-DBS, but quantitative intelligibility, perceptual, and acoustic studies have produced mixed and inconsi...
Preprint
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Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an effective and widely used tool in the treatment of Parkinson’s disease (PD). STN-DBS has varied effects on speech. Clinical speech ratings suggest worsening following STN-DBS, but quantitative intelligibility, perceptual, and acoustic studies have produced mixed and inconsi...
Article
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Studies of voice recognition in biology suggest that long exposure may not satisfactorily represent the voice acquisition process. The current study proposes that humans can acquire a newly familiar voice from brief exposure to spontaneous speech, given a personally engaging context. Studies have shown that arousing and emotionally engaging experie...
Article
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Contemporary imaging techniques have increased the potential for establishing how brain regions interact during spoken language. Some imaging methods report bilateral changes in brain activity during speech, whereas another approach finds that the relationship between individual variability in speech measures and individual variability in brain act...
Article
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Formulaic language forms about one-fourth of everyday talk. Formulaic (fixed expressions) and novel (grammatical language) differ in important characteristics. The features of idioms, slang, expletives, proverbs, aphorisms, conversational speech formulas, and other fixed expressions include ranges of length, flexible cohesion, memory storage, nonli...
Article
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Formulaic expressions naturally convey affective content. The unique formal and functional characteristics of idioms, slang, expletives, proverbs, conversational speech formulas, and the many other conventional expressions in this repertory have been well-described: these include unitary form, conventionalized and non-literal meanings, and reliance...
Article
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Language has been modeled as a rule governed behavior for generating an unlimited number of novel utterances using phonological, syntactic, and lexical processes. This view of language as essentially propositional is expanding as the role of formulaic expressions (e.g., you know, have a nice day, how are you?) is increasingly recognized. The basic...
Article
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Objective: Parkinson’s disease (PD), caused by basal ganglia dysfunction, is associated with motor disturbances including dysarthria. Stimulation of the subthalamic nucleus, a preferred treatment targeting basal ganglia function, improves features of the motor disorder, but has uncertain effects on speech. We studied speech during contrasting st...
Article
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This report describes an unusual presentation of a voice disorder arising from inability to coordinate the three components of motor speech: respiration, phonation, and articulation. These systems were individually intact, as demonstrated by laryngoscopy, motor speech examination, and treatment methods achieving success under controlled conditions....
Article
Rationale and objectives: Early prediction of incipient Alzheimer's disease (AD) dementia in individuals with mild cognitive impairment (MCI) is important for timely therapeutic intervention and identifying participants for clinical trials at greater risk of developing AD. Methods to predict incipient AD in MCI have mostly utilized cross-sectional...
Article
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Electrical stimulation of subthalamic nuclei (STN) is a widely used therapy in Parkinson’s disease (PD). While deep brain stimulation (DBS) of the STN alters the neurophysiological activity in basal ganglia, the therapeutic mechanism has not been established. A positron emission tomography (PET) study of cerebral blood flow (CBF) during speech prod...
Article
The effects of the DBS on speech remain controversial. This approach used intelligibility by listeners and acoustic parameters as measures of conversation and repeated speech. Persons with DBS-STN provided conversational speech samples and then repeated portions of their conversation in both on and off stimulation. Excerpts were arranged for a list...
Article
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Despite bilateral brain activation during speech tasks, we have shown that performance is predicted by a blood flow increase in the left inferior frontal region and decrease in the right caudate, consistent with classic lesion studies. This study characterized the structural connections between these brain areas using diffusion tensor imaging and e...
Article
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Background: Stimulation of the subthalamic nuclei (STN) is an effective treatment for Parkinson’s disease, but complaints of speech difficulties after surgery have been difficult to quantify. Speech measures do not convincingly account for such reports. Objective: This study examined STN stimulation effects on vowel production, in order to probe wh...
Article
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Adapted from the work of Kahana and colleagues (e.g., Kahana, 1996), we present two measures of order of recall in neuropsychological free recall tests. These are the position on the study list of the first recalled item, and the degree of variability in the order in which items are reported at test (i.e., the temporal distance across the first fou...
Article
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Production of formulaic expressions (conversational speech formulas, pause fillers, idioms, and other fixed expressions) is excessive in left hemisphere and deficient in right hemisphere and subcortical stroke. Alzheimer's (AD) speakers, having functional basal ganglia, reveal abnormally high proportions. Persons with Parkinson's disease (PD), havi...
Article
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Schemata are expressions that are fixed except for slots available for novel words (I’m not a …person). Our goals were to quantify speakers’ knowledge, examine semantic flexibility in open slots, and compare performance data in two generations of speakers using cloze procedures in formulaic expressions, schemata open slots, fixed portions of schema...
Article
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Background: Corpus callosum (CC) size and shape have been previously studied in Alzheimer's disease (AD) with the majority of studies having been cross-sectional. Due to the large variance in normal CC morphology, cross-sectional studies are limited in statistical power. Determining individual rates of change requires longitudinal data. Physiologi...
Article
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Vowels provide the acoustic foundation of communication through speech and song, but little is known about how the brain orchestrates their production. Positron emission tomography was used to study regional cerebral blood flow during sustained production of the vowel /a/. Acoustic and blood flow data from 13, normal, right-handed, native speakers...
Article
Background: The benzodiazepine lorazepam is widely utilized in the treatment of elderly individuals with anxiety disorders and related conditions. Negative effects of acute lorazepam administration on cognitive performance, especially memory, have been reported in both previously untreated elderly and in individuals who have received short term (u...
Article
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Background: Repetition occurs plentifully in normal conversation, but empirical studies of the pragmatic use of repetition are rare and pragmatic repetition, defined as verbal repetition in conversational use, in disordered language has not been systematically investigated. Applying a method of analysis that was piloted utilising normal discourse,...
Article
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The present study examined pausing patterns in spontaneous speech as a measure of the effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) on parkinsonian speech. Pauses reflect various aspects of speech and language processes, including motor initiation and linguistic planning. Relatively little attention has been given to pause...
Article
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Background: Alzheimer's disease (AD) has been shown to be associated with shrinkage of the corpus callosum mid-sagittal cross-sectional area (CCA). Objective: To study temporal rates of corpus callosum atrophy not previously reported for early AD. Methods: We used longitudinal MRI scans to study the rates of change of CCA and circularity (CIR)...
Article
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The corpus callosum (CC) is the largest fiber bundle connecting the left and right cerebral hemispheres. It has been a region examined extensively for indications of various pathologies, including Alzheimer's disease (AD). Almost all previous studies of the CC in AD have been concerned with its size, particularly its mid-sagittal cross-sectional ar...
Article
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One of the cognitive changes associated with Alzheimer's disease is a diminution of the primacy effect, i.e., the tendency toward better recall of items studied early on a list compared with the rest. We examined whether learning and recall of primacy words predicted subsequent cognitive decline in 204 elderly subjects who were non-demented and cog...
Article
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Initial shortening of stem vowels in three-word derivational paradigms (e.g., zip, zipper, zippering) was studied in persons with Parkinson's disease (PWPD) with and without deep brain stimulation (DBS), and in normal speakers. Seven PWPD without DBS, 7 PWPD with DBS ON (DBSN) or OFF (DBSF), and 6 healthy control (CON) persons were studied. Stimuli...
Article
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A special instance of formulaic expression is the linguistic schema: most of the expression is fixed, with one or more slots left open for insertion of novel words, such as I can _____ with one hand tied behind my back. This study aimed to determine whether native speakers demonstrate knowledge of the fixed portions of the schemata and flexibility...
Article
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The National Institute of Mental Health strategic plan for advancing psychiatric neuroscience calls for an acceleration of discovery and the delineation of developmental trajectories for risk and resilience across the lifespan. To attain these objectives, sufficiently powered datasets with broad and deep phenotypic characterization, state-of-the-ar...
Article
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A number of studies have reported that, "relative to brain size," the midsagittal corpus callosum cross-sectional area (CCA) in females is on average larger than in males. However, others suggest that these may be spurious differences created in the CCA-to-brain-size ratio because brain size tends to be larger in males. To help resolve this controv...
Article
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In motor speech disorders, dysarthric features impacting intelligibility, articulation, fluency and voice emerge more saliently in conversation than in repetition, reading or singing. A role of the basal ganglia in these task discrepancies has been identified. Further, more recent studies of naturalistic speech in basal ganglia dysfunction have rev...
Article
The Simplest Distinction in Functional Anatomy: Language LateralizationDo Imaging Signals Reflect the Mind, Neuronal Activity, or Something Else?Is More Better? Is More Necessary?Conceptual-Methodological IssuesHow Much Can We Really See?Functional Anatomy: What is the Appropriate Level of Resolution?Can We Interpret the Peaks Without the Valleys (...
Article
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Major depressive disorder is common in the elderly, and symptoms are often not responsive to conventional antidepressant treatment, especially in the long term. Soluble oligomeric and aggregated forms of amyloid beta peptides, especially amyloid beta 42, impair neuronal and synaptic function. Amyloid beta 42 is the main component of plaques and is...
Article
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Chronic, high-frequency electrical stimulation of the subthalamic nuclei (STNs) has become an effective and widely used therapy in Parkinson's disease (PD), but the therapeutic mechanism is not understood. Stimulation of the STN is believed to reorganize neurophysiological activity patterns within the basal ganglia, whereas local field effects exte...
Article
Full-text available
Connectivity analyses have become increasingly important in functional imaging. When used to describe the functional anatomy of a specific behavior, these analyses are generally applied to a subset of the data that demonstrate significant differences when experimental conditions are contrasted. Such data reduction is sub-optimal for a systems appro...
Article
Background: Healthy and cognitively-intact elderly carriers of APOE e4, an established risk factor for late-onset Alzheimer’s disease (LOAD), present more pronounced memory deficits following acute administration of lorazepam than non-e4 carriers. However, among non-e4 carriers, there is considerable individual variability. Variants in the length i...
Article
To the Editor: Dr Yaffe and colleagues reported that a lower β-amyloid 42/40 level in plasma was associated with greater cognitive decline during a 9-year period in nondemented elderly persons.1 Use of certain psychotropic medications, especially benzodiazepines2,3 and other medications with central anticholinergic effects,4,5 is quite common in el...
Article
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Advances in neurobiology are providing new opportunities to investigate the neurological systems underlying motor speech control. This study explores the perceptual characteristics of the speech of three genotypes of spino-cerebellar ataxia (SCA) as manifest in four different speech tasks. Speech samples from 26 speakers with SCA were perceptually...
Article
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A variable poly-T polymorphism in the TOMM40 gene, which is in linkage disequilibrium with APOE, was recently implicated with increased risk and earlier onset age for late-onset Alzheimer's disease in APOE ε3 carriers. To elucidate potential neurobiological mechanisms underlying this association, we compared the effect of TOMM40 poly-T variants to...
Article
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Speaking, which naturally occurs in different modes or "tasks" such as conversation and repetition, relies on intact basal ganglia nuclei. Recent studies suggest that voice and fluency parameters are differentially affected by speech task. In this study, the authors examine the effects of subcortical functionality on voice and fluency, comparing me...
Article
The monoamine hypothesis ascribes an important role to the under activity of brain monoamines such as 5-HT, noradrenaline and dopamine to the pathophysiology of depression. This view emerged more than 50 years ago and has guided development of most medications currently used for the treatment of this disorder. However, large numbers of depressed in...
Article
Retrograde facilitation (RF) of information learned prior to acute oral administration of trihexyphenidyl, a preferential muscarinic M1 receptor antagonist which impairs new learning, was studied in 24 healthy elderly subjects. The relationship between the RF induced by this anticholinergic drug and the APOE epsilon4 allele was also examined. Acute...