Assessments with Double Simultaneous Tactile Stimulation following Stroke: A Scoping Review Protocol

Abstract

Intact somatosensory perception is essential to interact with our surrounding environment, including when performing basic daily tasks and learning skilled movements. Successful execution of voluntary movements depends on accurately processing and perceiving the incoming somatosensory information through integrated sensorimotor pathways. Somatosensory impairments following stroke are relatively common, affecting upwards of 85% of survivors living with stroke. Loss of tactile perception is among the most frequent occurring of the somatosensory impairments, impacting approximately 50% of these individuals in the USA. Common tactile impairments include hypoesthesia (reduced ability to feel touch), dysesthesia (abnormal tactile perception), and impaired two-point discrimination (reduced ability to discriminate between two nearby locations of touch). These impairments are often assessed using unilateral tactile stimulation on the more severely-affected (paretic) side, and, accordingly, do not capture more complex tactile impairments that can arise during bilateral interactions. One such impairment is tactile extinction (TE), a condition in which individuals can detect unilateral tactile stimuli on either side of the body but fail to perceive the same tactile stimuli on the paretic side when both sides are stimulated simultaneously. Most activities of daily living rely on coordinating touching and feeling of objects and using both upper extremities to manipulate them in a dynamic manner, such that both arms are stimulated. Tactile dysfunction that suppresses perception during such bilateral tasks can disrupt motor performance in daily activities and recovery. Therefore, understanding the nature of tactile dysfunction during bilateral tasks following stroke is valuable when considering how to effectively assess and, in turn, treat individuals. In this scoping review, we will explore approaches to assess tactile perceptual dysfunction during bilateral interactions post-stroke. Our aim is to summarize the current status of double simultaneous tactile stimulation approaches used for assessing tactile dysfunction. By considering the design of these approaches, we will identify need for further research, such as additional methods for assessment and implications of existing methods for interpreting why bilateral tactile dysfunction arises following stroke.