Cancer related cognitive impairment (CRCI) is a common side effect of treatment of cancer during and after chemotherapy and is seen in patients with non-central nervous system( non-CNS) cancer. Though common after chemotherapy, other treatments such as hormone therapies and targeted therapies can also cause cognitive deficits.. The self-reported prevalence of cognitive complains in cancer survivors was 75% in a large web based study with non CNS cancers . The clinical presentation of these cognitive impairments include memory deficits, difficulty with learning attention, concentration, reasoning, processing speed, executive functions and visuospatial skills. Therefore the cognitive impairment can have a negative impact on quality of life, daily functioning and ability to work in patients with cancer while undergoing treatment and while in remission.

Acquired Peripheral Neuropathy (APN) is another common side effect of treatment for cancer. While majority of the peripheral neuropathy symptoms are due to neurotoxic chemotherapy agents resulting in chemotherapy-induced peripheral neuropathy (CIPN), neuropathy symptoms can also occur as paraneoplastic, immune-mediated, or neoplastic neuropathies. The reported prevalence of CIPN is 68% within first month after chemotherapy and continued to be present in 47% of the survivors even 6 years later. The clinical presentation of the CIPN includes numbness, tingling, or burning, neuropathic pain, decrease of muscle tone and coordination, and loss of balance. The symptoms tends to begin distally in the fingers and toes and moves proximally through the extremities. CIPN is typically associated with treatment using platinum based drugs, taxanes, epothilones, vinca alkaloids, bortezomib and thalidomide.

Individuals with CIPN are significantly more likely to suffer falls and fall related injuries. In breast cancer survivors with neuropathy, 40.9% experienced falls on both flat surfaces and non-flat surfaces during upright activities. Gait is a complex functional activity that requires the integration of the musculoskeletal, sensory, neurological, and cognitive systems. Significant gait variability in step width and step length with forward walking has been reported in cancer survivors with peripheral neuropathy compared to healthy controls. However, normal daily walking does not include just walking in a forward direction, but rather it involves walking in different directions such as walking backwards to sit in a chair. Although gait variability has been reported with forward walking, the gait variability while walking backwards in patients with cancer with APN has not been investigated previously.

Cognitive impairment has been strongly associated with decreased performance in dual task abilities and higher number of falls in older adults. Performing concurrent tasks such as walking and talking or walking and texting is a normal aspect of life. Concurrent performance of two tasks with distinct motor and cognitive demands has been associated with increased fall risk in older adults. Ability to do such dual task (DT) has shown to be declined in persons with cognitive and motor impairments. Ability to perform DT has been also reported to be affected in persons with diabetic peripheral neuropathy. There is only one reported study that evaluated the cognitive and sensory deficits associated with orbital stability in gait on treadmill during single and dual task in cancer survivors with and without peripheral neuropathy. However, walking on the treadmill at fixed speed does not translate to the real-world adaptations on overground walking in different directions with the added challenge of a cognitive task. Though cognitive and peripheral neuropathy symptoms are reported in patients with non- CNS cancers who are undergoing treatment and while in remission, ability to perform dual task with forward and backward walking has not been assessed in this population and not compared with an age and gender matched control without peripheral neuropathy. Additionally, it is important to investigate what cognitive, motor and sensory impairments can predict fall risk and decreased quality of life in this population compared to an age and gender matched control.

The purpose of this proposed exploratory pilot study is to evaluate the dual task cost of variable walking in individuals diagnosed with cancer treatment induced peripheral neuropathy compared to age and gender matched individuals without peripheral neuropathy. backward walking on an over ground computerized mat. A secondary purpose will be to identify what type of cognitive, motor and sensory impairments can correlate quality of life in individuals diagnosed with cancer treatment induced peripheral neuropathy and can predict fall risk in this population compared to compared to age and gender.