DSpace Repository :: Browsing by Author "Attaripour, Sanaz"

Browsing by Author "Attaripour, Sanaz"

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BacAv, a new free online platform for clinical back-averaging
(2020) Vial Undurraga, Felipe; Attaripour, Sanaz; McGurrin, Patrick; Hallett, Mark
Objective. The back-average technique is very useful to study the relation between the activity in the cortex and the muscles. It has two main clinical applications, Bereitschaftspotential (BP) recording and myoclonus studies. The BP is a slow wave negativity originating in the supplementary motor cortex and premotor cortex that precedes voluntary movements. This wave also precedes involuntary movements in functional movement disorders (FMD), and it can be used as a helpful diagnostic tool. For the myoclonus studies, the back-average technique is very important to help localizing the source of the myoclonus. The hardware needed to do BP or myoclonus studies is standard and available in any electrophysiology lab, but there are not many software solutions to do the analysis. In this article together with describing the methodology that we use for recording clinical BPs and myoclonus, we present BacAv, an online free application that we developed for the purpose of doing back-average analysis. Methods: BacAv was developed in “R” language using Rstudio, a free integrated development environment. The recommended parameters for the data acquisition for BP recording and myoclonus studies are given in this section. Results: The platform was successfully developed, is able to read txt files, look for muscle bursts, segment the data, and plot the average. The parameters of the algorithm that look for the muscle bursts can be adapted according to the characteristics of the dataset. Conclusion: We have developed software for clinicians who do not have sophisticated equipment to do back-averaging. Significance: This tool will make this useful analysis method more available in a clinical environment.
Differentiating tics from functional (psychogenic) movements with electrophysiological tools
(2019) Vial, Felipe; Attaripour, Sanaz; Hallett, Mark
Objective: We report on two patients that presented to our clinic with the differential diagnosis of functional movement disorder vs tic disorder. Case reports: The first patient is a 23-year-old woman with a 3-year history of repetitive involuntary neck flexion movements. The second patient is a 59-year-old man with a 10-month history of involuntary trunk jerks. In both cases, the polyelectromyographic study and the observation of Bereitschaftspotential helped us in making the final diagnosis. Significance: The use of electrophysiological tools can be helpful in making the distinction between functional movement disorders and tic disorders.
Electrophysiological Evidence for Functional (Psychogenic) Essential Palatal Tremor
(2020) Vial Undurraga, Felipe; Akano, Emmanuel; Attaripour, Sanaz; McGurrin, Patrick; Hallett, Mark
Background: There is little published work describing the electrophysiological characteristics of essential palatal tremor, a condition now believed by many to be a functional (psychogenic) movement disorder. Case Report: Here we combine electroencephalography and electromyography with time-locked video recordings to document two cases of essential palatal tremor in which a definitive diagnosis is achieved using these electrophysiological tools. Discussion: We believe that sharing how these objective tools can be used to diagnose a functional movement disorder, as well as providing more published evidence to support the functional origin of essential palatal myoclonus, will help to diagnose this condition in the future.
KCNN2 Mutation in Pediatric Tremor Myoclonus Dystonia Syndrome with Electrophysiological Evaluation
(2022) Lavenstein, Bennett; McGurrin, Patrick; Attaripour, Sanaz; Vial Undurraga, Felipe; Hallett, Mark
Background: Here we combine clinical, electrophysiological, and genetic findings to phenotype an unusual childhood movement disorder in a patient with a rare form of KCNN2 mutation. Case report: A 10-year-old male presented with a clinical syndrome of tremor and myoclonus. Electrophysiology demonstrated muscle activity indicative of myoclonus dystonia, an observation that was not appreciated clinically. Genetic testing revealed an abnormality in the KCNN 2 gene, not present in the parents, known to cause dystonia, as the etiology. Discussion: The value of utilizing noninvasive, electrophysiological recording in pediatric movement disorders expands the precision of diagnosis, potentially informing treatment when correlated with clinical and genetic findings.
Patterns of brain activity in choice or instructed go and no-go tasks
(2025) Attaripour, Sanaz; McGurrin, Patrick; Vial Undurraga, Felipe; Hallett, Mark
The goal of this study was to investigate the decision making process for choosing what movements to make. We used electroencephalography (EEG) to investigate patterns of the contingent negative variation (CNV) associated with free-choice decisions to move or abstain, comparing them to conditions where actions were commanded. Our primary hypothesis was that choice tasks would differ significantly from each other and exhibit EEG patterns akin to their command-driven counterparts after the decisions were made, at least, in the 50 ms block of time prior to movement. A secondary analysis evaluated post hoc comparisons of time, in 50 ms blocks, to understand the temporal development of the CNV for each condition. We also conducted an exploratory analysis of EEG event-related desynchronization (ERD) to identify patterns of brain activity associated with the decision-making process. This approach was taken due to the exploratory nature of our hypotheses concerning the spatial and temporal characteristics of EEG activity during these free-choice versus commanded tasks. We studied 12 right-handed healthy volunteers (7 women, mean age 53 years, range 39-73 years) with no prior history of neurological or major psychiatric illness. A CNV paradigm encompassing commanded and choice tasks was devised, with a 2500 ms interval between S1 and S2, while recording EEG and electromyography (EMG). S1 provided full information about the upcoming task, which was to be executed at the time of S2. We assessed CNV and explored whole scalp EEG activity, including both voltage as well as power in the alpha and beta frequency ranges. Clear and similar CNVs were observed for command and choice go tasks prior to the movements, contrasting with near-zero CNVs for the command and choice no-go tasks. Separation of CNVs for command go and no-go tasks occurred around 1600 ms post-S1, and choice CNVs separated about 2150 ms post-S1. Exploratory analysis revealed that beta power provided information about decision and preparation processes much earlier. The left dorsolateral prefrontal cortex (DLPFC) exhibited the initial sign of decision approximately 500 ms post-S1 for all tasks, with subsequent preparation for movement or restraint involving distinct activity in various brain regions. The localization of effects in the left DLPFC was determined by visual analysis of the informative electrode sites. The CNVs separate about 2 s after S1, and it appears that this process represents preparation for movement (or no movement). Exploration of the beta activity suggests an earlier decision process which leads eventually to subsequent task preparation and activation. Choice decisions lag slightly behind command decisions, with the CNV apparently reflecting motor implementation rather than the decision-making process. In a simple motor task with an exploratory analysis, both commanded and choice-based decisions are rapidly initiated in the left DLPFC. While the CNV distinguishes between go and no-go conditions, it primarily appears to signify preparation for implementation of the task following the earlier decision. Further controlled studies will be needed to confirm these results.
Purposely Induced Tics: Electrophysiology
(2020) McGurrin, Patrick; Attaripour, Sanaz; Vial Undurraga, Felipe; Hallett, Mark
Tics are non-rhythmic movements that can be simple or complex. Clinically, they may appear as quick voluntary movements (50–200 ms), but can also be longer and more sustained (>300 ms). These movements are often described as being predictable. An inner tension builds which is relieved by the movement in most cases, and the movement can be suppressed for some time. Most patients report a feeling of relief once they release the movement, and therefore do not prolong the suppression. Thus, to some extent, the movement is under voluntary control. Tics have been called “unvoluntary”; a movement between voluntary and involuntary behavior.4 Here we present a person who can purposely induce tics. Simultaneous electroencephalography (EEG) and electromyographic (EMG) activity were recorded to capture the Bereitschaftspotential (BP) to explore the physiology of this phenomenon.

Browsing by Author "Attaripour, Sanaz"

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