# Efficacy of Trihexyphenidyl on Apraxia of Eyelid Opening in Parkinsonism: A Case Report

## TL;DR

A 64-year-old woman with Parkinsonism developed eyelid-opening issues, which were effectively treated with trihexyphenidyl.

## Contribution

This case report demonstrates the efficacy of trihexyphenidyl in treating apraxia of eyelid opening in Parkinsonism.

## Key findings

- Trihexyphenidyl (THP) dramatically improved the patient's apraxia of eyelid opening.
- Other antiparkinsonian medications failed to alleviate the patient's AEO symptoms.
- The case suggests a potential therapeutic pathway for managing AEO in Parkinsonism.

## Abstract

Apraxia of eyelid opening (AEO) is occasionally seen in Parkinson’s disease (PD) or related diseases. However, many clinicians have trouble with the management of AEO by Parkinsonism. In this report, we describe a case of AEO in Parkinsonism improved by trihexyphenidyl (THP). The patient was a 64-year-old woman, who was previously healthy but developed bradykinesia. She was clinically diagnosed as PD due to an L-dopa challenge test, but no other detailed tests were performed. She started antiparkinsonian medications and her symptoms were improved at an early phase. However, her motor symptoms were gradually exacerbated over time, and antiparkinsonian medications were dosed up. At 69 years old, blepharospasm and AEO developed. Although other antiparkinsonian medications did not improve her AEO, THP cured AEO dramatically at 73 years old. In this report, we discuss a mechanism of AEO by Parkinsonism and the pathway of THP for the improvement of AEO.