# SURVEY OF CHANGES IN SUBJECTIVE SYMPTOMS AMONG JAPANESE POLIO SURVIVORS OVER 10 YEARS

## TL;DR

This study tracks how muscle weakness and atrophy changed over 10 years in Japanese polio survivors, finding differences between younger and older groups.

## Contribution

The study provides new insights into long-term subjective symptom progression in polio survivors by comparing younger and older groups.

## Key findings

- Muscle atrophy and weakness progressed in both upper and lower limbs over 10 years.
- Younger survivors experienced more weakness in the poor lower limbs, while older survivors had it in good lower and poor upper limbs.
- Fatigue decreased among participants over the study period.

## Abstract

To define long-term changes in subjective symptoms among polio survivors in Japan.

Prospective cohort study.

Sixty-five polio survivors.

Surveys were conducted on subjective symptoms including muscle weakness and limb atrophy during 2007 and 2021. The results of manual muscle tests of the upper and lower limbs on both sides during 2007 were summed and scored, and the side with lower scores was defined as the poor side. The participants were classified as younger or older groups based on the median age at the first survey (i.e., 58 years old) and the subjective symptoms were compared between the two groups.

As a whole, muscle atrophy and weakness progressed in the lower and upper limbs while fatigue was reduced. Muscle weakness progressed especially in the lower limbs on the poor side in the younger group, and in the older group it progressed in the lower limbs on the good side and the upper limbs on the poor side.

The timing of progressive muscle weakness differed between the upper and lower limbs of younger and older polio survivors.

Poliomyelitis causes muscle weakness, often in good and poor limbs. Although polio survivors frequently develop post-poliomyelitis syndrome that comprises new muscle weakness, long-term changes remain unclear. We investigated changes in subjective symptoms, especially muscle weakness on the good and poor sides, in 65 Japanese polio survivors with a median age of 58 years at the time of diagnosis over > 10 years. An evaluation of degrees of muscle weakness in the upper and lower limbs and symptoms revealed increased muscle weakness and atrophy. Muscle weakness was progressive in the poor lower limbs of younger survivors and in the good lower limbs and poor upper limbs of older survivors. The timing of progressive muscle weakness differed between the upper and lower limbs of younger and older polio survivors.