Quantitative Static and Dynamic Assessment of Balance Control in Stroke Patients

The human body can maintain posture stability under various conditions, including internal and external disturbances¹. Balance relies on sensory input, integration of the central nervous system (CNS), and motor control². In patients with stroke, damage to the CNS can affect the ability to maintain balance³. Postural instability is an important risk factor for falls⁴. Approximately 70% of patients experience a fall in the first year after stroke, often with serious consequences, such as hip fracture in elderly patients^5,6. Moreover, previous studies have shown that postural sway and increased motor response time to visual stimuli are associated with an increased fall risk^7,8. Because strokes have a substantial impact on mobility, accurate qualitative and quantitative balance assessment is important for understanding the type, extent, cause of balance deficit, as well as guidance for individualized interventions and appropriate gait aids⁹.

Clinical assessment methods for balance can be broadly divided into observation, scale assessment, and balance instrument testing. Observation methods (e.g., the Romberg test¹⁰) are only used as a rough screening for patients with balance dysfunction due to their strong subjectivity. Many balance function scales are commonly used in clinical practice because of their ease-of-use, economy, and relative quantification. These include the Tinetti scale¹¹, Berg Balance Scale (BBS)¹², Fugl-Meyer Assessment (FMA)¹³, and Timed Up and Go (TUG) test¹². These clinical tests are not suitable for determining the fall risk in patients with significant balance disorders, because they are subjective assessments and often are not able to substantiate the self-reported balance problems experienced by individuals with mild-to-moderate balance problems¹⁴. Balance instrument testing, a posturography technique, is a useful tool to quantitatively measure the static and dynamic balance function and require balance evaluation systems, such as a force tilting board with pressure sensors, computers, monitors, balance control panels, and professional balance analysis software. These approaches can assess the degree, type, or cause of the balance damage simultaneously by accurately measuring the center of gravity (COG) and postural sway, thereby precisely and objectively reflecting the patient’s balance function. Balance instrument testing can detect subtle differences or damages that the clinical scales cannot. This can be used to overcome the ceiling effect of the scale assessment. With the increasing application of posturography techniques and popularization of computers, it is necessary to promote objective/quantitative balance assessment into clinical practice.

This article describes a clinical balance assessment method that includes standard clinical balance scales and three-module instrument objective balance assessment for stroke patients with balance disorders. A comparison of the results of the clinical assessment scales versus the instrumental balance assessment, is presented to show the advantages of instrumental balance assessment, especially for stroke patients with mild balance disorders. This protocol can help health professionals achieve accurate evaluation to guide clinical treatments. The representative posturography instrument (see Table of Materials) used in this protocol has been validated for dynamic assessment and statistic assessment in previous studies^15,16,17. The system, which is composed of a screen monitor and a tilting board where the patients stand, can be used for evaluating the visual, auditory, and proprioceptive feedback of the patients.