Great Toe Strength (GTS) is a potential clinical biomarker that has been associated with functional mobility and health; Additionally, GTS has been identified in the literature as one of the early symptoms of chemotherapy-induced peripheral neuropathy (CIPN). The purpose of this research study is to evaluate GTS in individuals with CIPN and healthy adults using ToeScale and see how it relates to nerve issues from chemotherapy. Additionally, we aim to assess the usability of the novel GTS assessment device, ToeScale among the participants. As a part of this study visit, you will complete some questionnaires followed by GTS and balance and gait assessments.

Chemotherapy-induced peripheral neuropathy, or CIPN, is a common side effect of cancer treatment. It affects about 30-40% of people with cancer and up to 100% of those who receive chemotherapy that can harm nerves. One of the early signs of CIPN is weakness in the muscles of the great toe, which is associated with movement and balance.

Current methods used to measure the strength of the great toe muscles have several drawbacks. They are not very sensitive to changes in strength, require expensive equipment or trained professionals, and can be subjective. To address these limitations, a new portable device called ToeScale was developed. This study aims to:

1. Check if the ToeScale device is a valid measure of great toe strength (GTS) in people with CIPN and how different GTS is among age- and sex- matched healthy adults.
2. Explore the relationship between great toe strength and the severity of CIPN symptoms.
3. Assess how easy it is for participants to use the ToeScale device.

In simpler terms, this study wants to see if the new device is reliable and accurate, how well it measures GTS in people with CIPN, and whether it's easy to use.

Eligibility Criteria for Chemotherapy-Induced Peripheral Neuropathy (CIPN) group:

Inclusion Criteria:

• At least 18 years of old with the ability to independently raise and low (extend or flex) the great toe
• Able to consent and complete questionnaires in English independently and have normal to corrected vision (self-reported)
• Within 3 - 6 months of starting chemotherapy and a confirmed diagnosis of CIPN using the current clinical reference standard of Nerve conduction study.

Exclusion Criteria:

• Comorbidities including but not limited to diabetes, arthritis, hypertension, thyroid disease, and heart disease, . that have been reported to be associated with the incidence of peripheral neuropathy and/or progression of CIPN.
• Toe deformities or impairments not caused by CIPN (including but not limited to hallux valgus/varus, hallux limitus, hallux rigidus, hammer toe deformity, claw toe, bunions, webbed toes)
• Self-reported impairment or impact on the strength of the foot, ankle, and/or great toe due to past medical or surgical history.

Eligibility Criteria for Healthy Control group: The participants recruited for this group will be age- and sex- matched to the CIPN group

• Inclusion Criteria:
• At least 18 years of old with the ability to independently raise and low (extend or flex) the great toe
• Able to consent and complete questionnaires in English independently and have normal to corrected vision (self-reported)
• No known health conditions that have been reported to be associated with different impairements in mobility, balance, and muscle strength (particularly in the lower extremity)

Individuals with CIPN and age- and sex- matched healthy controls will be recruited for this study. The recruitment will primarily rely on the resources availale through and rehabilitation specialists working within the University of Florida (UF) Health Cancer Center as well as UF Health Hospitals.

The de-identified data might be shared with permission from the funder and PI per request and as appropriate.

After completion of study and publication of the results from the primary outcomes.

Only de-identified data will be shared with permission from the funder and PI per request.