Energy Expenditure Index Correlates with Motor and Sensory Impairments and Disease Severity in Adrenomyeloneuropathy
Man Amanat1, Christopher F. Joseph1, Jennifer Keller1, Gerald Raymond2, Bela Turk1, Ali Fatemi1, Amena Fine1
1Kennedy Krieger Institute, 2Medical Genetics, Johns Hopkins School of Medicine
Objective:
This study aimed to assess whether energy expenditure index (EEI) after the fast walking in individuals with adrenomyeloneuropathy (AMN) is associated with perceived exertion, impaired gait, postural sway, spasticity, and disease severity.
Background:
AMN is a progressive X-linked peroxisomal disorder presenting during adulthood. AMN is long tract disorder involving dorsal columns and corticospinal tracts, characterized by sensory ataxia, spastic paraparesis and bowel/bladder dysfunction. The ratio of heart rate (HR) per meter walk is a valid scale to represent energy consumption during walking and is known as the EEI.
Design/Methods:
We conducted a cross-sectional analysis of baseline data collected from a clinical trial in adults with AMN. Perceived exertion was quantified in patients using the modified Borg scale (MBS). Gait parameters were measured by 3D motion capture at fast walking and postural sway was assessed in four static standing positions. The Ashworth scale and expanded disability status scale (EDSS) were used to evaluate spasticity and disease severity, respectively. The analysis was performed using multiple linear regressions adjusted for age and weight of participants.
Results:
Fifty-seven individuals (35 females and 22 males) with recorded resting HR and walking HR after the fast walking were included. EEI was significantly associated with MBS in both females (R2: 0.44, P-value: 0.0001) and males (R2: 0.68, P-value: 0.0001). Among females, EEI was correlated with cadence (R2: 0.35, P-value: 0.0001), stride length (R2: 0.32, P-value: 0.0003), double support time (R2: 0.29, P-value: 0.006), spasticity (R2: 0.22, P-value: 0.004), and pyramidal EDSS (R2: 0.18, P-value: 0.009). EEI was associated with pyramidal EDSS (R2: 0.39, P-value: 0.001), spasticity (R2: 0.39, P-value: 0.001), and cadence (R2: 0.27, P-value: 0.003) among males.
Conclusions:
AMN symptoms correlate with increased effort with mobility, and EEI may be a mean to measure the impact of the severity of AMN symptoms on patients' quality of life.