CAN GAIT ANALYSIS AID DIFFERENTIAL DIAGNOSIS OF DEMENTIA DISEASE SUBTYPES?

Abstract

Background Diagnostic distinction between diseases causing dementia subtypes is hindered by clinical and pathological similarities, particularly between Alzheimer's disease (AD) and Lewy body dementias (LBD). Accurate diagnosis is fundamental for efficient treatment and management of conditions. Therefore, strengthening diagnostic accuracy through clinical tools, such as gait analysis, is essential. Safe gait involves complex cognitive processes and gait impairment predicts cognitive impairments. The study aims to assess if dementia subtypes have unique signatures of gait with potential to aid differential diagnosis. Methods 92 participants were recruited across three groups; 33 AD ((mean±sd) Age: 78±7; MMSE: 23±4), 29 LBD (Age: 76±6; MMSE: 24±3) and 30 controls (Age:74±9; MMSE: 29±1). Dementia disease subtypes ranged in severity from mild cognitive impairment to moderate dementia. Gait was assessed using an instrumented walkway (GAITRite) under single-task walking conditions. A battery of cognitive tests were employed. Kruskall Wallis and Mann Whitney U tests were used to investigate group differences. Results Preliminary results report significant gait impairments in LBD compared to AD for measures of speed (step velocity (p≤.05); Figure 1), variability (swing, step time, stance and step length variability (p≤.05)), timing (stance (p≤.05)) and asymmetry (step time asymmetry (p≤.05)). Compared with controls both dementia subtypes showed impairments for measures of speed (step velocity, step length (p≤.05)), variability (swing, step time, stance, step velocity, step length variability (p≤.05)), timing (stance (p≤.05)) and postural control of gait (step width (p≤.05)). LBD also had significant impairments in rhythm (step time (p≤.05)) compared to controls. For cognitive tests, increased impairments in executive function (Trail Making Task A; (p≤.05)) and attention (simple (p≤.05)) and choice reaction time tasks (p≤.05)) in LBD differentiated subtypes. Conclusions Results support literature identifying gait impairments in dementia, strengthening its potential as a clinical biomarker. Dementia subtypes are distinguishable by degree rather than pattern of impairment. This may reflect damage to the prefrontal cortex, an area involved in mediating gait, attentional and executive processes. Early during LBD and later in AD, this region is affected. Distinguishing attention and executive abilities further provided evidence of prefrontal involvement. Future research must establish gait's specificity, in addition to sensitivity, as a diagnostic tool.