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- Creators: Daliri, Ayoub
- Member of: Theses and Dissertations
Description
Previous research has showed that auditory modulation may be affected by pure tone
stimuli played prior to the onset of speech production. In this experiment, we are examining the
specificity of the auditory stimulus by implementing congruent and incongruent speech sounds in
addition to non-speech sound. Electroencephalography (EEG) data was recorded for eleven adult
subjects in both speaking (speech planning) and silent reading (no speech planning) conditions.
Data analysis was accomplished manually as well as via generation of a MATLAB code to
combine data sets and calculate auditory modulation (suppression). Results of the P200
modulation showed that modulation was larger for incongruent stimuli than congruent stimuli.
However, this was not the case for the N100 modulation. The data for pure tone could not be
analyzed because the intensity of this stimulus was substantially lower than that of the speech
stimuli. Overall, the results indicated that the P200 component plays a significant role in
processing stimuli and determining the relevance of stimuli; this result is consistent with role of
P200 component in high-level analysis of speech and perceptual processing. This experiment is
ongoing, and we hope to obtain data from more subjects to support the current findings.
stimuli played prior to the onset of speech production. In this experiment, we are examining the
specificity of the auditory stimulus by implementing congruent and incongruent speech sounds in
addition to non-speech sound. Electroencephalography (EEG) data was recorded for eleven adult
subjects in both speaking (speech planning) and silent reading (no speech planning) conditions.
Data analysis was accomplished manually as well as via generation of a MATLAB code to
combine data sets and calculate auditory modulation (suppression). Results of the P200
modulation showed that modulation was larger for incongruent stimuli than congruent stimuli.
However, this was not the case for the N100 modulation. The data for pure tone could not be
analyzed because the intensity of this stimulus was substantially lower than that of the speech
stimuli. Overall, the results indicated that the P200 component plays a significant role in
processing stimuli and determining the relevance of stimuli; this result is consistent with role of
P200 component in high-level analysis of speech and perceptual processing. This experiment is
ongoing, and we hope to obtain data from more subjects to support the current findings.
ContributorsTaylor, Megan Kathleen (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Transcranial Current Stimulation (TCS) is a long-established method of modulating neuronal activity in the brain. One type of this stimulation, transcranial alternating current stimulation (tACS), is able to entrain endogenous oscillations and result in behavioral change. In the present study, we used five stimulation conditions: tACS at three different frequencies (6Hz, 12Hz, and 22Hz), transcranial random noise stimulation (tRNS), and a no-stimulation sham condition. In all stimulation conditions, we recorded electroencephalographic data to investigate the link between different frequencies of tACS and their effects on brain oscillations. We recruited 12 healthy participants. Each participant completed 30 trials of the stimulation conditions. In a given trial, we recorded brain activity for 10 seconds, stimulated for 12 seconds, and recorded an additional 10 seconds of brain activity. The difference between the average oscillation power before and after a stimulation condition indicated change in oscillation amplitude due to the stimulation. Our results showed the stimulation conditions entrained brain activity of a sub-group of participants.
ContributorsChernicky, Jacob Garrett (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel out the resulting sensory feedback. Currently, there are no published accounts of the perception of tactile signals for motor tasks and contexts related to the lips during both speech planning and production. In this study, we measured the responsiveness of the somatosensory system during speech planning using light electrical stimulation below the lower lip by comparing perception during mixed speaking and silent reading conditions. Participants were asked to judge whether a constant near-threshold electrical stimulation (subject-specific intensity, 85% detected at rest) was present during different time points relative to an initial visual cue. In the speaking condition, participants overtly produced target words shown on a computer monitor. In the reading condition, participants read the same target words silently to themselves without any movement or sound. We found that detection of the stimulus was attenuated during speaking conditions while remaining at a constant level close to the perceptual threshold throughout the silent reading condition. Perceptual modulation was most intense during speech production and showed some attenuation just prior to speech production during the planning period of speech. This demonstrates that there is a significant decrease in the responsiveness of the somatosensory system during speech production as well as milliseconds before speech is even produced which has implications for speech disorders such as stuttering and schizophrenia with pronounced deficits in the somatosensory system.
ContributorsMcguffin, Brianna Jean (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown that SEM enhances single joint movements that are usually performed with difficulty. While the presence of SEM in the stroke survivor population advances scientific understanding of movement capabilities following a stroke, published studies using the SEM phenomenon only examined one joint. The ability of SEM to generate multi-jointed movements is understudied and consequently limits SEM as a potential therapy tool. In order to apply SEM as a therapy tool however, the biomechanics of the arm in multi-jointed movement planning and execution must be better understood. Thus, the objective of our study was to evaluate if SEM could elicit multi-joint reaching movements that were accurate in an unrestrained, two-dimensional workspace. Data was collected from ten subjects with no previous neck, arm, or brain injury. Each subject performed a reaching task to five Targets that were equally spaced in a semi-circle to create a two-dimensional workspace. The subject reached to each Target following a sequence of two non-startling acoustic stimuli cues: "Get Ready" and "Go". A loud acoustic stimuli was randomly substituted for the "Go" cue. We hypothesized that SEM is accessible and accurate for unrestricted multi-jointed reaching tasks in a functional workspace and is therefore independent of movement direction. Our results found that SEM is possible in all five Target directions. The probability of evoking SEM and the movement kinematics (i.e. total movement time, linear deviation, average velocity) to each Target are not statistically different. Thus, we conclude that SEM is possible in a functional workspace and is not dependent on where arm stability is maximized. Moreover, coordinated preparation and storage of a multi-jointed movement is indeed possible.
ContributorsOssanna, Meilin Ryan (Author) / Honeycutt, Claire (Thesis director) / Schaefer, Sydney (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Startle-evoked-movement (SEM), the involuntary release of a planned movement via a startling stimulus, has gained significant attention recently for its ability to probe motor planning as well as enhance movement of the upper extremity following stroke. We recently showed that hand movements are susceptible to SEM. Interestingly, only coordinated movements of the hand (grasp) but not individuated movements of the finger (finger abduction) were susceptible. It was suggested that this resulted from different neural mechanisms involved in each task; however it is possible this was the result of task familiarity. The objective of this study was to evaluate a more familiar individuated finger movement, typing, to determine if this task was susceptible to SEM. We hypothesized that typing movements will be susceptible to SEM in all fingers. These results indicate that individuated movements of the fingers are susceptible to SEM when the task involves a more familiar task, since the electromyogram (EMG) latency is faster in SCM+ trials compared to SCM- trials. However, the middle finger does not show a difference in terms of the keystroke voltage signal, suggesting the middle finger is less susceptible to SEM. Given that SEM is thought to be mediated by the brainstem, specifically the reticulospinal tract, this suggest that the brainstem may play a role in movements of the distal limb when those movements are very familiar, and the independence of each finger might also have a significant on the effect of SEM. Further research includes understanding SEM in fingers in the stroke population. The implications of this research can impact the way upper extremity rehabilitation is delivered.
ContributorsQuezada Valladares, Maria Jose (Author) / Honeycutt, Claire (Thesis director) / Santello, Marco (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The brain uses the somatosensory system to interact with the environment and control movements. Additionally, many movement disorders are associated with deficits in the somatosensory sensory system. Thus, understanding the somatosensory system is essential for developing treatments for movement disorders. Previous studies have extensively examined the role of the somatosensory system in controlling the lower and upper extremities; however, little is known about the contributions of the orofacial somatosensory system. The overall goal of this study was to determine factors that influence the sensitivity of the orofacial somatosensory system. To measure the somatosensory system's sensitivity, transcutaneous electrical current stimulation was applied to the skin overlaying the trigeminal nerve on the lower portion of the face. After applying stimulation, participants' sensitivity was determined through the detection of the electrical stimuli (i.e., perceptual threshold). The data analysis focused on the impact of (1) stimulation parameters, (2) electrode placement, and (3) motor tasks on the perceptual threshold. The results showed that, as expected, stimulation parameters (such as stimulation frequency and duration) influenced perceptual thresholds. However, electrode placement (left vs. right side of the face) and motor tasks (lip contraction vs. rest) did not influence perceptual thresholds. Overall, these findings have important implications for designing and developing therapeutic neuromodulation techniques based on trigeminal nerve stimulation.
ContributorsKhoury, Maya Elie (Author) / Daliri, Ayoub (Thesis advisor) / Patten, Jake (Committee member) / Liss, Julie (Committee member) / Arizona State University (Publisher)
Created2022
Description
Objective: Previous studies have observed that adults with dyslexia display a reduced N1 gating when exposed to repetitive stimuli. Robust gating is associated with the ability to recognize familiar stimuli and identify the stimuli that will need novel memory representations formed. This study investigates if the mismatch negativity component in electroencephalographic-produced Event-Related Potentials (ERPs) is affected as well by diminished memory forming in adults with dyslexia. Additionally, signal/ noise processing for auditory-based memory recollection and thus word learning is explored. Methods: Nineteen adults with dyslexia and 18 adult controls participated in a classic auditory oddball electroencephalographic experiment here referred to as DIFF, to indicate that the tones differed in frequency, while incorporating a decision-making task that signified participant tonal discrimination. Mismatch Negativity (MMN) amplitudes (AMPs) and latencies were collected from ERPs. Behavioral data consisting of reaction time (RT) and accuracy (ACC) of tone choice were documented.
Results: Group differences for accuracy and reaction time in the DIFF task were highly significant. The dyslexic group produced longer reaction times and with less accuracy than the control group. The Mismatch Negativity amplitude and latency collected did not differ significantly between groups, however, correlations to other variables obtained from similar studies consisting of the same participant group were observed. Linear regression models indicated predictions for accuracy and reaction time results based upon WID scores (Word Identification Test) and SWE scores (Sight Word Efficiency) respectfully.
Conclusions: Neural processing speed and the ability to form permanent memory representations of auditory sound bites for retrieval is dampened in dyslexic populations.
Significance: To better illuminate and understand the neural mechanisms of dyslexia, specifically auditory processing, with the goal of improving outcomes in individuals with dyslexia through more efficient therapy treatment options.
ContributorsAbrams, Gabrielle Renee (Author) / Peter, Beate (Thesis advisor) / Rogalsky, Corianne (Committee member) / Rao, Aparna (Committee member) / Arizona State University (Publisher)
Created2022
Description
Stroke is the leading cause of long-term disability in the U.S., with up to 60% of strokescausing speech loss. Individuals with severe stroke, who require the most frequent, intense speech therapy, often cannot adhere to treatments due to high cost and low success rates. Therefore, the ability to make functionally significant changes in individuals with severe post- stroke aphasia remains a key challenge for the rehabilitation community. This dissertation aimed to evaluate the efficacy of Startle Adjuvant Rehabilitation Therapy (START), a tele-enabled, low- cost treatment, to improve quality of life and speech in individuals with severe-to-moderate stroke. START is the exposure to startling acoustic stimuli during practice of motor tasks in individuals with stroke. START increases the speed and intensity of practice in severely impaired post-stroke reaching, with START eliciting muscle activity 2-3 times higher than maximum voluntary contraction. Voluntary reaching distance, onset, and final accuracy increased after a session of START, suggesting a rehabilitative effect. However, START has not been evaluated during impaired speech. The objective of this study is to determine if impaired speech can be elicited by startling acoustic stimuli, and if three days of START training can enhance clinical measures of moderate to severe post-stroke aphasia and apraxia of speech. This dissertation evaluates START in 42 individuals with post-stroke speech impairment via telehealth in a Phase 0 clinical trial. Results suggest that impaired speech can be elicited by startling acoustic stimuli and that START benefits individuals with severe-to-moderate post-stroke impairments in both linguistic and motor speech domains. This fills an important gap in aphasia care, as many speech therapies remain ineffective and financially inaccessible for patients with severe deficits. START is effective, remotely delivered, and may likely serve as an affordable adjuvant to traditional therapy for those that have poor access to quality care.
ContributorsSwann, Zoe Elisabeth (Author) / Honeycutt, Claire F (Thesis advisor) / Daliri, Ayoub (Committee member) / Rogalsky, Corianne (Committee member) / Liss, Julie (Committee member) / Schaefer, Sydney (Committee member) / Arizona State University (Publisher)
Created2022
Description
Speech and music are traditionally thought to be primarily supported by different hemispheres. A growing body of evidence suggests that speech and music often rely on shared resources in bilateral brain networks, though the right and left hemispheres exhibit some domain-specific specialization. While there is ample research investigating speech deficits in individuals with right hemisphere lesions and amusia, fewer investigate amusia in individuals with left hemisphere lesions and aphasia. Many of the fronto-temporal-parietal regions in the left hemisphere commonly associated with speech processing and production are also implicated in bilateral music processing networks. The current study investigates the relationship between damage to specific regions of interest within these networks, and an individual’s ability to successfully match the pitch and rhythm of a presented melody. Twenty-seven participants with chronic-stroke lesions were given a melody repetition task to hum short novel piano melodies. Participants underwent structural MRI acquisition and were administered an extensive speech and cognitive battery. Pitch and rhythm scores were calculated by correlating participant responses and target piano notes. Production errors were calculated by counting trials with responses that don’t match the target melody’s note count. Overall, performance varied widely, and rhythm scores were significantly correlated. Working memory scores were significantly correlated with rhythm scores and production errors, but not pitch scores. Broca’s area lesions were not associated with significant differences in any of the melody repetition measures, while left Heschl’s gyrus lesions were associated with worse performance on pitch, rhythm, and production errors. Lower rhythm scores were associated with lesions including both the left anterior and posterior superior temporal gyrus, and in participants with damage to the left planum temporale. The other regions of interest were not consistently associated with poorer pitch scores or production errors. Although the present study does have limitations, the current study suggests lesions to left hemisphere regions thought to only affect speech also affect musical pitch and rhythm processing. Therefore, amusia should not be characterized solely as a right hemisphere disorder. Instead, musical abilities of individuals with left hemisphere stroke and aphasia should be characterized to better understand their deficits and mechanisms of impairment.
ContributorsWojtaszek, Mallory (Author) / Rogalsky, Corianne (Thesis advisor) / Daliri, Ayoub (Committee member) / Patten, Kristopher (Committee member) / Arizona State University (Publisher)
Created2022
Description
Studies using transcranial direct current stimulation (tDCS) to enhance motor training areoften irreproducible. This may be partly due to differences in stimulation parameters across
studies, but it is also plausible that uncontrolled placebo effects may interact with the true
‘treatment’ effect of tDCS. Thus, the purpose of this study was to test whether there was a
placebo effect of tDCS on motor training and to identify possible mechanisms of such an effect.
Fifty-one participants (age: 22.2 ± 4.16; 26 F) were randomly assigned to one of three groups:
active anodal tDCS (n=18), sham tDCS (n=18), or no stimulation control (n=15). Participant
expectations about how much tDCS could enhance motor function and their general suggestibility
were assessed. Participants then completed 30 trials of functional upper extremity motor training
with or without online tDCS. Stimulation (20-min, 2mA) was applied to the right primary motor
cortex (C4) in a double-blind, sham-controlled fashion, while the control group was unblinded and
not exposed to any stimulation. Following motor training, expectations about how much tDCS
could enhance motor function were assessed again for participants in the sham and active tDCS
groups only. Results showed no effect of active tDCS on motor training (p=.67). However, there
was a significant placebo effect, such that the collapsed sham and active tDCS groups improved
more during motor training than the control group (p=.02). This placebo effect was significantly
influenced by post-training expectations about tDCS (p=.0004). Thus, this exploratory study
showed that there is a measurable placebo effect of tDCS on motor training, likely driven by
participants’ perceptions of whether they received stimulation. Future studies should consider
placebo effects of tDCS and identify their underlying mechanisms in order to leverage them in
clinical care.
ContributorsHAIKALIS, NICOLE (Author) / Schaefer, Sydney Y (Thesis advisor) / Honeycutt, Claire (Committee member) / Daliri, Ayoub (Committee member) / Arizona State University (Publisher)
Created2022