Objective: The supplementary motor area (SMA) demonstrates abnormal beta activity (13-30 Hz) during speech and limb movement tasks in neurological conditions such as Parkinson's disease (PD). Transcranial Alternating Current Stimulation (tACS) has demonstrated promising improvements in motor and non-motor functions by entraining endogenous neural oscillations. We conducted an exploratory study on the modulatory effects of personalized beta high-definition (HD)-tACS over the left SMA on speech production and limb movement.
View Article and Find Full Text PDFSpinal Cord Stimulation (SCS) has been a cornerstone in managing chronic pain since the late 1960s. However, traditional SCS is often associated with variable efficacy and side effects, driving the development of advanced techniques like high-frequency SCS (hSCS). Previous studies have demonstrated that the power of high-frequency cerebral oscillations increases as a function of stimulus intensity and plays a critical role in local neural processing of peripheral sensory stimuli.
View Article and Find Full Text PDFJ Fluency Disord
March 2025
Non-invasive neuromodulation methods such as transcranial Direct Current Stimulation (tDCS) and Transcranial Magnetic Stimulation (TMS), have been extensively utilized to enhance treatment efficacy for various neurogenic communicative disorders. Recently, these methods have gained attention for their potential to reveal more about the underlying nature of stuttering and serve as adjunct therapeutic approaches for stuttering intervention. In this review, we present existing research and discuss critical factors that might influence the efficacy of these interventions, such as location, polarity, intensity, and duration of stimulation, as well as the impact of combined behavioral training.
View Article and Find Full Text PDFTransient disruption or permanent damage to the left Frontal Aslant Tract (FAT) is associated with deficits in speech production. The present study examined the application of theta (4 Hz) high-definition transcranial alternating current stimulation (HD-tACS) over the left SMA and IFG -as a part of FAT- as a potential multisite protocol to modulate neural and behavioral correlates of speech motor control. Twenty-one young adults participated in three counterbalanced sessions in which they received in-phase, anti-phase, and sham theta HD-tACS.
View Article and Find Full Text PDFBackground: Deep brain stimulation (DBS) reliably ameliorates cardinal motor symptoms in Parkinson's disease (PD) and essential tremor (ET). However, the effects of DBS on speech, voice and language have been inconsistent and have not been examined comprehensively in a single study.
Objective: We conducted a systematic analysis of literature by reviewing studies that examined the effects of DBS on speech, voice and language in PD and ET.
The supplementary motor area (SMA) is implicated in planning, execution, and control of speech production and limb movement. The SMA is among putative generators of pre-movement EEG activity which is thought to be neural markers of motor planning. In neurological conditions such as Parkinson's disease, abnormal pre-movement neural activity within the SMA has been reported during speech production and limb movement.
View Article and Find Full Text PDFEvidence suggests that speech and limb movement inhibition are subserved by common neural mechanisms, particularly within the right prefrontal cortex. In a recent study, we found that cathodal stimulation of right dorsolateral prefrontal cortex (rDLPFC) differentially modulated P3 event-related potentials for speech versus limb inhibition. In the present study, we further analyzed these data to examine the effects of cathodal high-definition transcranial direct current stimulation (HD-tDCS) over rDLPFC on frontal theta - an oscillatory marker of cognitive control - in response to speech and limb inhibition, during a Go/No-Go task in 21 neurotypical adults.
View Article and Find Full Text PDFEvents are a fundamentally important part of our understanding of the world. How lexical concepts denoting events are represented in the brain remains controversial. We conducted two experiments using event and object nouns matched on a range of psycholinguistic variables, including concreteness, to examine spatial and temporal characteristics of event concepts.
View Article and Find Full Text PDFEvidence suggests that perceptual and action related features of concepts are grounded in the corresponding sensory-motor networks in the human brain. However, less is known about temporal features of event concepts (e.g.
View Article and Find Full Text PDFFront Psychiatry
August 2023
Objective: Substance use disorder (SUD) is a significant public health issue with a high mortality rate. Deep brain stimulation (DBS) has shown promising results in treating SUD in certain cases. In this study, we conducted a meta-analysis to evaluate the efficacy of DBS in the treatment of SUD and reduction of relapse rates.
View Article and Find Full Text PDFEvidence suggests that planning and execution of speech and limb movement are subserved by common neural substrates. However, less is known about whether they are supported by a common inhibitory mechanism. P3 event-related potentials (ERPs) is a neural signature of motor inhibition, which are found to be generated by several brain regions including the right dorsolateral prefrontal cortex (rDLPFC).
View Article and Find Full Text PDFFront Hum Neurosci
February 2023
Deep brain stimulation (DBS) of the subthalamic nucleus (STN), which consistently improves limb motor functions, shows mixed effects on speech functions in Parkinson's disease (PD). One possible explanation for this discrepancy is that STN neurons may differentially encode speech and limb movement. However, this hypothesis has not yet been tested.
View Article and Find Full Text PDFExperimental evidence suggests that modality-specific concept features such as action, motion, and sound partially rely on corresponding action/perception neural networks in the human brain.Little is known, however, about time-related features of concepts. We examined whether temporal features of concepts recruit networks that subserve time perception in the brain in an EEG study using event and object nouns.
View Article and Find Full Text PDFFront Hum Neurosci
September 2022
The contribution of action-perception systems of the brain to lexical semantics remains controversial. Here, we used high-definition transcranial direct current stimulation (HD-tDCS) in healthy adults to examine the role of primary (left hand motor area; HMA) and higher-order (left anterior inferior parietal lobe; aIPL) action areas in action-related word processing (action verbs and manipulable nouns) compared to non-action-related control words (non-action verbs and non-manipulable nouns). We investigated stimulation-related effects at three levels of semantic processing: subliminal, implicit, and explicit.
View Article and Find Full Text PDFBush et al. (2022) highlight that brain recordings examining speech production can be significantly affected by microphonic artifact, which would change the interpretation of these kinds of data. While these findings are vital in determining whether data are artifactual or physiological in origin, frequencies were only examined up to 250 Hz (i.
View Article and Find Full Text PDFCommunication difficulties are a ubiquitous symptom of Parkinson's disease and include changes to both motor speech and language systems. Communication challenges are a significant driver of lower quality of life. They are associated with decreased communication participation, social withdrawal, and increased risks for social isolation and stigmatization in persons with Parkinson's disease.
View Article and Find Full Text PDFPurpose: Subthalamic nucleus (STN) and globus pallidus interna (GPI) are the two most common sites for deep brain stimulation (DBS) in people with Parkinson's disease (PWP). Voice impairments are a common symptom of Parkinson's disease and information about voice outcomes with DBS is limited. Most studies in speech-language pathology have focused on STN-DBS and few have examined the effects of GPI-DBS.
View Article and Find Full Text PDFObjective: We used a classical motor reaction time paradigm to examine the effects of Parkinson's disease (PD) on the mechanisms of speech production and upper limb movement.
Methods: Electro-encephalography (EEG) signals were recorded in PD and control groups during speech vowel production and button press tasks in response to temporally predictable and unpredictable visual stimuli.
Results: Motor reaction times were slower in PD vs.
Neuropsychologia
August 2021
The extent to which action and perception systems of the brain are involved in semantic comprehension remains controversial. Whether figurative language, such as metaphors and idioms, is grounded in sensory-motor systems is especially contentious. Here, we used high-definition transcranial direct current stimulation (HD-tDCS) in healthy adults to examine the role of the left-hemisphere motor cortex during the comprehension of action sentences, relative to comprehension of sentences with visual verbs.
View Article and Find Full Text PDFNeuropsychologia
November 2020
Parkinson's disease (PD), which involves basal ganglia degeneration, affects language as well as motor function. However, which aspects of language are impaired in PD and under what circumstances remains unclear. We examined whether lexical and grammatical aspects of language are differentially affected in PD, and whether this dissociation is moderated by sex as well as the degree of basal ganglia degeneration.
View Article and Find Full Text PDFDeveloping a clearer understanding of impairments that underlie the behavioral characteristics of aphasia is essential for the development of targeted treatments and will help inform theories of speech motor control. Impairments in sensorimotor integration of speech in individuals with conduction aphasia have previously been implicated in their repetition deficits. However, much less is known about the extent to which these integrative deficits occur outside of conduction aphasia and how this manifests behaviorally in areas other than speech repetition.
View Article and Find Full Text PDFNormal aging is associated with decline of motor timing mechanisms implicated in planning and execution of movement. Evidence from previous studies has highlighted the relationship between neural oscillatory activities and motor timing processing in neurotypical younger adults; however, it remains unclear how normal aging affects the underlying neural mechanisms of movement in older populations. In the present study, we recorded EEG activities in two groups of younger and older adults while they performed randomized speech and limb motor reaction time tasks cued by temporally predictable and unpredictable sensory stimuli.
View Article and Find Full Text PDFNeural interactions between sensorimotor integration mechanisms play critical roles in voice motor control. We investigated how high-definition transcranial direct current stimulation (HD-tDCS) of the left ventral motor cortex modulates neural mechanisms of sensorimotor integration during voice motor control. HD-tDCS was performed during speech vowel production in an altered auditory feedback (AAF) paradigm in response to upward and downward pitch-shift stimuli.
View Article and Find Full Text PDFJ Neurolinguistics
August 2019
Parkinson's disease (PD), which involves the degeneration of dopaminergic neurons in the basal ganglia, has long been associated with motor deficits. Increasing evidence suggests that language can also be impaired, including aspects of syntactic and lexical processing. However, the exact pattern of these impairments remains somewhat unclear, for several reasons.
View Article and Find Full Text PDFNeurological deficits can cause a wide range of motor symptoms in patients with Parkinson's disease (PD). However, our understanding about the effects of PD on the underlying neural mechanisms of motor function has remained elusive. In the present study, we investigated the relationship between PD pathology and neurological deficits in planning and execution mechanisms of motor timing during speech production and limb movement.
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