NEW ORLEANS—Performance Scale Severity Score (PSSS) tables may allow patients and their physicians to easily compare functional impairment of a patient with multiple sclerosis (MS) to that of other patients with similar MS duration, according to research presented at the 64th Annual Meeting of the American Academy of Neurology.
“PSSS tables provide a snapshot of perceived disease impact on 11 neurologic domains across disease lifespan,” said Ilya Kister, MD, Assistant Professor of Neurology at New York University (NYU) Langone Medical Center, New York City, and colleagues.
“[The tables] could assist clinicians and patients in choosing the disease-modifying therapy commensurate with relative disease severity,” he added.
Scoring Domain-Specific Impairment
The study’s reference population derives from the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry, which collects self-reported data from 29,904 patients in 11 neurologic domains—cognition, depression, pain, fatigue, vision, hand function, mobility, spasticity, bowel/bladder, sensory, and tremor. A domain-specific, six- or seven-grade Performance Scale is used to score impairment in each of the domains.
For each of the 11 Performance Scales, Dr. Kister and his colleagues from the NYU School of Medicine and the University of Alabama at Birmingham School of Public Health calculated the percent of patients in each impairment grade for each of the first 30 years of disease.
Tracking Increasing Disease Severity
In the first 15 years following symptom onset, the percentage of patients in the more severe grades continued to increase across all 11 neurologic domains as disease duration increased.
The domains of cognition, depression, and pain had little change in severity during the last 15 years of observation, while the domains of mobility, spasticity, bowel/bladder, hand function, and fatigue showed a shift to the more severe grades throughout the observation period.
The researchers noted that the prevalence of severe impairment in patients with MS was probably underestimated, as patients with the most severe disease are less likely to self-register into the NARCOMS registry.
However, the NARCOMS cohort exhibits similar mobility impairment to that of most published cohorts (greater than 50% of patients needed to use a cane on a daily basis after approximately 15 years of disease).
Prevalence Tables May Enhance Understanding
Dr. Kister believes that the prevalence tables may be a useful tool for clinicians and patients. “Our data provide a ‘natural history’ of MS symptoms in a large database,” he told Neurology Reviews. “This information is not available elsewhere.
“[Our data] give patients and doctors a sense of how MS affects patients throughout the disease and allow a patient to see how well he or she is doing, relative to other patients who had disease for the same duration,” Dr. Kister concluded.