Deficits in startle-evoked arm movements increase with impairment following stroke

Honeycutt, Claire F.; Perreault, Eric J.

doi:10.1016/j.clinph.2013.12.102

Cited by 21 publications

(30 citation statements)

References 58 publications

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“…Previous reports at the elbow showed inappropriate flexor activity that lead to deviations away from stroke subject's intended target (Honeycutt and Perreault, 2012, Honeycutt and Perreault, 2013); however we did not find evidence of this in the hand indicated by a strong similarity between voluntary and startReact movement traces. It was previously hypothesized that the inappropriate flexor activity results from an unsuppressed classic startle reflex - the adoption of a crouched stance that is dominated by flexor activity in the upper limb (Honeycutt and Perreault, 2012).…”

Section: Discussioncontrasting

confidence: 99%

“…During startReact trials, the GO signal was replaced by a startling, high-intensity acoustic stimulus (128 dB) emitted from a loud speaker located behind the subject's head. StartReact protocols are similar to those in previous reports (Honeycutt, Kharouta, 2013, Honeycutt and Perreault, 2012, Honeycutt and Perreault, 2013). Command signals for WARNING, GO, and the startling acoustic stimulus were generated in MatLab and their analog signals recorded to ensure they were delivered at the appropriate latency.…”

Section: Methodssupporting

confidence: 67%

“…Further, we evaluated only moderately to mildly impaired individuals. The inappropriate flexor activity at the elbow is more dominant in more severely impaired individuals (Honeycutt and Perreault, 2013). …”

Section: Discussionmentioning

confidence: 99%

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Startling acoustic stimuli can evoke fast hand extension movements in stroke survivors

Honeycutt

Tresch

Perreault

2015

Clinical Neurophysiology

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Objective A startling loud acoustic stimulus can involuntarily elicit planned movements, a phenomenon referred to as startReact. Following stroke, startReact elbow flexion in stroke survivors are improved from voluntary movements. Specifically, startReact elbow flexion in unimpaired individuals is not statistically different from stroke survivors in terms of onset latency and muscle activation patterns. As hand movements are particularly impacted by stroke, our objective was to determine if startReact was intact in the hand following stroke. Methods Data were collected in 8 stroke survivors and 10 age-matched subjects performing hand extension following two non-startling acoustic stimuli representing “get ready” and “go” respectively. Randomly, the “go” was replaced with a startling acoustic stimulus. We hypothesized that 1) startReact would be intact during hand extension in stroke survivors and 2) that the latency of movement would be the same as in age-matched subjects. Results We found that startReact was intact in stroke subjects and further that the onset latency of these movements was not different from age-matched subjects. Conclusions We conclude that startReact is intact in the hand following stroke. Significance An intact startReact response indicates that this reflex may be an attractive therapeutic target for initiating hand extension in stroke survivors.

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Section: Discussioncontrasting

confidence: 99%

Section: Methodssupporting

confidence: 67%

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Startling acoustic stimuli can evoke fast hand extension movements in stroke survivors

Honeycutt

Tresch

Perreault

2015

Clinical Neurophysiology

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“…Previous studies have shown that startReact is robust across multiple individual joints, but startReact has also been shown to be more variable in kinematics such as mean peak displacement and peak angular velocity (Carlsen et al 2004a). Many previous studies restricted all joints not specifically related to the task (Carlsen et al 2004a; Maslovat et al 2011; Honeycutt and Perreault 2012, 2013) raising the question of whether startReact would be accurate during unrestricted multi-joint movements that more closely resemble functional reaching movements in everyday environments. Further, previous work to date (including our own) has primarily utilized statistical models that test for differences, not similarity, leaving in doubt if startReact movements were truly similar or simply “not different.” Our results show that multi-joint startReact movements are indeed equivalent to voluntarily-initiated movement demonstrating that startReact evokes a sophisticated motor plan with tuned direction, force, and muscle activation patterns that can be involuntarily initiated.…”

Section: Discussionmentioning

confidence: 99%

Startle evokes nearly identical movements in multi-jointed, two-dimensional reaching tasks

et al. 2018

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StartReact is the ability of the startle reflex to involuntarily release a planned movement in the presence of a loud acoustic stimulus resulting in muscle activity patterns and kinematics that are tightly regulated and scaled with the intended action. Previous studies demonstrated startReact’s robustness during simple single-joint reaching tasks and found no difference between startReact and voluntary movements for movement kinematics and muscle activation patterns. However, startReact has not been evaluated during multi-joint reaching movements with multiple degrees of freedom. It is unclear if startReact would evoke accurate and precise multi-joint reaching movements in an unrestricted workspace. Furthermore, if tested more rigorously, multi-joint startReact movement kinematics and muscle activation patterns might not be truly equivalent despite showing no difference through traditional ANOVAs. A previous study found multi-joint startReact was possible during unrestricted elbow and shoulder movement when reaching to a forward target. Therefore, we hypothesized that startReact would evoke similar multi-joint reaching movements for movement accuracy and muscle activation patterns when compared to voluntary movements in a multi-directional workspace. Expanding upon the previous study, our study uses a larger workspace and fully evaluates movement kinematics and muscle activations patterns. Results confirmed our hypothesis and found startReact movements were readily evoked in all directions. StartReact responses presented stereotypically earlier muscle activation, but the relative timing of agonist/antagonist firing pairs between startReact and voluntary movements remained similar. Results demonstrate that startReact is robustly present and equivalent in multi-joint reaching tasks and has potential clinical use for evaluating healthy and impaired movement.

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“…Unlike some other authors [4, 12, 13], we included all SAS trials in our analyses, regardless of whether a startle reflex was observed in SCM. Some previous studies on upper limb movements have reported small differences in SAS-induced reaction times between SCM+ and SCM− trials and argued that a startle reflex appears to be conditional to the StartReact effect [6, 7, 14].…”

Section: Discussionmentioning

confidence: 99%

A startling acoustic stimulus facilitates voluntary lower extremity movements and automatic postural responses in people with chronic stroke

et al. 2018

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A startling acoustic stimulus (SAS) involuntary releases prepared movements at accelerated latencies, known as the StartReact effect. Previous work has demonstrated intact StartReact in paretic upper extremity movements in people after stroke, suggesting preserved motor preparation. The question remains whether motor preparation of lower extremity movements is also unaffected after stroke. Here, we investigated StartReact effects on ballistic lower extremity movements and on automatic postural responses (APRs) following perturbations to standing balance. These APRs are particularly interesting as they are critical to prevent a fall following balance perturbations, but show substantial delays and poor muscle coordination after stroke. Twelve chronic stroke patients and 12 healthy controls performed voluntary ankle dorsiflexion movements in response to a visual stimulus, and responded to backward balance perturbations evoking APRs. Twenty-five percent of all trials contained a SAS (120 dB) simultaneously with the visual stimulus or balance perturbation. As expected, in the absence of a SAS muscle and movement onset latencies at the paretic side were delayed compared to the non-paretic leg and to controls. The SAS accelerated ankle dorsiflexion onsets in both the legs of the stroke subjects and in controls. Following perturbations, the SAS accelerated bilateral APR onsets not only in controls, but for the first time, we also demonstrated this effect in people after stroke. Moreover, APR inter- and intra-limb muscle coordination was rather weak in our stroke subjects, but substantially improved when the SAS was applied. These findings show preserved movement preparation, suggesting that there is residual (subcortical) capacity for motor recovery.

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Deficits in startle-evoked arm movements increase with impairment following stroke

Cited by 21 publications

References 58 publications

Startling acoustic stimuli can evoke fast hand extension movements in stroke survivors

Startling acoustic stimuli can evoke fast hand extension movements in stroke survivors

Startle evokes nearly identical movements in multi-jointed, two-dimensional reaching tasks

A startling acoustic stimulus facilitates voluntary lower extremity movements and automatic postural responses in people with chronic stroke

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