Objective: To recognize the increase eye blink rate (EBR) as a potential motor fluctuation (MF) in a PD patient undergoing levodopa treatment

Background: A normal EBR is 12-20 blinks per minute (BPM) , mean 17 BPM [1]. PD typically shows decreased EBR (~7 BPM). Increased EBR is linked to LID, with dyskinetic patients differing from non-dyskinetic and healthy controls. Advanced PD can show a threefold EBR increase post-levodopa [2]. Kimber and Thompson found two PD patterns: low “off” EBR rising with levodopa, and high “off” EBR decreasing after levodopa, suggesting altered dopamine receptor sensitivity [3]

Method: A 63-year-old female diagnosed with PD 8 years ago, treated with levodopa for 6 years (daily LED: 750 mg). Over the last year, she reported an increased EBR associated with biphasic LID, interfering with daily activities. EBR was assessed during clinical evaluations using a one-minute direct count method, following standard protocols used in prior studies

Results: EBR was assessed by counting blinks per minute during a routine clinical exam. At the onset of a 187.5 mg levodopa dose, EBR reached 82 BPM, far exceeding the normal range (12-20 BPM). This increase coincided with biphasic trunk and limb LID, aligning with the patient’s reported visual disturbances and functional impairment due to excessive blinking.

After optimizing treatment by increasing levodopa frequency and adding pramipexole, a reduction in both trunk LID and EBR was observed. During follow-up, EBR decreased to 20 BPM, within the upper normal limit. This improvement correlated with reduced visual discomfort and better daily function, supporting the hypothesis that EBR may serve as an early indicator of MF and a therapeutic response marker in PD.

Conclusion: The observed EBR increase correlates with LID and functional impairment, highlighting its value as an objective marker for treatment-related complications. This case supports evidence that EBR reflects “on” and “off” states in advanced PD, reinforcing its relevance in clinical practice. Further research is needed to validate its role in monitoring and managing MF, as timely treatment adjustments may reduce LID impact, improving functional independence and quality of life.

References: 1. Bentivoglio AR, Bressman SB, Cassetta E, Carretta D, Tonali P, Albanese A. Analysis of blink rate patterns in normal subjects. Mov Disord. 1997;12(6):1028-1034. doi:10.1002/mds.870120629
2.Karson CN, LeWitt PA, Calne DB, Wyatt RJ. Blink rates in parkinsonism. Ann Neurol. 1982 Dec;12(6):580-3. doi: 10.1002/ana.410120614. PMID: 7159063.
3.Kimber TE, Thompson PD. Increased blink rate in advanced Parkinson’s disease: a form of ‘off’-period dystonia?. Mov Disord. 2000;15(5):982-985. doi:10.1002/1531-8257(200009)15:5<982::aid-mds1033>3.0.co;2-p

« Back to 2025 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/increase-eye-blink-rate-as-a-motor-fluctuation-in-levodopa-induced-dyskinesia-in-parkinsons-disease-a-forgotten-indicator-of-motor-fluctuations-a-case-report/