# Clinical Characteristics of Parkinsonism in HTLV‐1‐Associated Myelopathy

## TL;DR

This study found that 4.5% of HTLV-1-associated myelopathy patients also had parkinsonism, which was linked to older age and more severe symptoms.

## Contribution

The study identifies parkinsonism as a rare but significant feature of HTLV-1-associated myelopathy, expanding its known clinical spectrum.

## Key findings

- 4.5% of HAM/TSP patients had parkinsonism, with a significantly older age of onset compared to typical HAM/TSP.
- P-HAM patients showed greater motor disability despite a shorter illness duration.
- No laboratory differences were found between P-HAM and typical HAM/TSP cases.

## Abstract

Human T‐lymphotropic virus type 1 (HTLV‐1)‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) is the classic neurological manifestation of HTLV‐1 infection; however, this virus has also been associated with other neurological disorders. Concurrent parkinsonism is relatively rare and presents diagnostic challenges. The present study aimed to identify the clinical characteristics of HAM/TSP with parkinsonism.

This retrospective study included HAM/TSP patients hospitalized in Kagoshima University Hospital from January 2000 to March 2022. Clinical and laboratory findings of the HAM/TSP patients with parkinsonism (P‐HAM) were collected from the medical records and compared with HAM/TSP patients without parkinsonism (typical HAM/TSP [T‐HAM]). P‐HAM cases were defined as patients presenting with any combination of rigidity, resting tremor, bradykinesia, and/or postural instability, with these symptoms not attributed to HAM/TSP.

Of 246 HAM/TSP patients, 11 (4.5%) presented with parkinsonism. Compared with T‐HAM, the age of onset was significantly older (65.0 vs. 48.8 years, p = 0.001) in patients with P‐HAM. Moreover, despite a shorter illness duration (8.5 vs. 12.5 years, p = 0.151), the Osame Motor Disability Score was significantly higher in P‐HAM cases than in T‐HAM cases (6.3 vs. 4.6, p = 0.0132), and all P‐HAM cases had scores ≥ 4. Laboratory findings showed no differences between the groups.

In our cohort, 4.5% of HAM/TSP patients had concomitant parkinsonism, which was associated with a later age of onset and greater disease severity. The coexistence of parkinsonism in HAM/TSP may be underrecognized, and our findings expand the clinical spectrum of neurological disease with HTLV‐1 infection.