# Upper-Extremity Torque Perceptual Impairments in Chronic Hemiparetic Stroke

> **NIH NIH K25** · NORTHWESTERN UNIVERSITY · 2020 · $128,229

## Abstract

Project Summary
 In the USA, 5.6 million individuals with stroke face great difficulty performing activities of daily living, probably
in part because they are unable to accurately judge the forces they generate with their two arms. The impact of
this impairment on completing activities of daily living is unknown, but prior work suggests that the effect is
substantial, particularly during bimanual tasks. I propose to examine the cause of the impairment, as well as to
quantify its magnitude during unimanual and bimanual perceptual tasks. Furthermore, I propose to assess the
plausibility of my novel hypothesis to explain the reason for force perceptual impairments by using a mechanistic
probe. During the experimental testing, I will use custom mechatronic systems of my own design to control the
user’s applied forces and to obtain quantitative outcome measures. Based on findings from this proposal, I will
gain an improved understanding of the extent to which force perceptual impairments impact sensorimotor ability
of individuals with stroke when executing unimanual and bimanual tasks.
 We know that after a hemiparetic stroke an individual’s paretic arm lacks the strength and control of their
non-paretic arm. Therefore, these individuals with stroke must relearn to use their arms to interact with the
world. For unimanual tasks, they normally relearn how to use each arm independently. For bimanual tasks,
individuals with stroke nearly always learn to use their paretic arm to assist their non-paretic arm, not vice
versa. Consequently, I propose the following novel central hypothesis: force perception is i) intact within
each arm during unimanual tasks and ii) impaired only in the unusual condition when the non-paretic arm
must assist the paretic arm to execute bimanual tasks. In turn, I propose that force perceptual impairments
are important to investigate since they may hinder the ability of individuals with stroke to safely deal with
unfamiliar and potentially dangerous bimanual tasks, such as when a knife slips while slicing a tomato.
 My proposed research and training plan benefits from its ability to unite engineers, neuroscientists, and
clinicians to quantify changes in force perception following stroke. To test my central hypothesis, I will assess
elbow force perceptual ability during unimanual and bimanual tasks, and I will test the neuroplasticity of
force perceptual impairments by using bimanual training. Combined with my proposed automated,
quantitative, mechatronic assessment tools, I provide a novel approach to mitigating maladaptive changes to
perception following stroke and other brain injuries. Knowledge gained from this proposal can change the way
clinicians approach rehabilitation by highlighting the importance of intact force perception during daily activities.

## Key facts

- **NIH application ID:** 9948709
- **Project number:** 5K25HD096116-03
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Netta Gurari
- **Activity code:** K25 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $128,229
- **Award type:** 5
- **Project period:** 2018-08-20 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9948709

## Citation

> US National Institutes of Health, RePORTER application 9948709, Upper-Extremity Torque Perceptual Impairments in Chronic Hemiparetic Stroke (5K25HD096116-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9948709. Licensed CC0.

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