Levodopa Improves Handwriting, Dexterity Tasks in Parkinson’s Patients, Study Indicates

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by Forest Ray PhD |

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Levodopa improved handwriting and dexterity tasks among people living with Parkinson’s disease, a recent study found.

The results, “Levodopa improves handwriting and instrumental tasks in previously treated patients with Parkinson’s disease,” were published in the Journal of Neural Transmission.

Neurological examinations of Parkinson’s patients that seek to quantify motor function impairment can vary between different examiners and may make it a struggle to detect subtle changes.

Two scientists in Germany contend that the execution of three standardized tasks — handwriting, line tracing, and peg insertion — may provide additional useful information about the functioning and impairment of people with Parkinson’s, when tested on and off medication.

These results, they hypothesized, would enable doctors to evaluate a patient’s response to dopamine.

To test this, the researchers had 38 hospitalized, right-handed Parkinson’s patients without unpredictable motor fluctuations and who were receiving treatment, take a series of tests with and without levodopa medication.

Tests consisted of writing a simple sentence (“Bochum ist eine schöne Stadt,” or “Bochum is a pretty city”) three times on unlined white paper and at a comfortable speed, transferring 25 pegs from a rack into one of 25 holes, and following a grooved path with a stylus as quickly and exactly as possible.

Participants first performed these tasks after being taken off their regular medications for 12 hours and being assessed by the Unified Parkinson’s Disease Rating Scale (UPDRS I-IV), a scale that assesses both motor and non-motor symptoms of Parkinson’s.

Patients then received one tablet of Madopar LT (100 mg of levodopa/25 mg benserazide), dissolved in 100 mL water. One hour later, they underwent assessment on the UPDRS part III, which specifically assesses motor symptoms, of the right arm and then repeated the tasks.

After medication, UPDRS III scores decreased, indicating an improvement in motor function, as did the time it took participants to complete the writing task. The average time to complete that task decreased from approximately 29 seconds to 25.

Similarly, peg insertion and line tracing times also declined following medication. Average peg insertion time dropped from nearly six seconds to 5.4 seconds and line tracing from 1.8 to 1.5 seconds.

Errors made while tracing the line, such as drawing outside the grooves, and the duration of those errors declined significantly while on the medication, from approximately 38 errors over six seconds to nearly 30 errors over 4.6 seconds.

Despite not being able to rule out the possible lasting effects of patients’ other medications, or the effect of different individual onsets and maximum response times to the levodopa treatment, the study showed positive evidence that these handwriting and instrumental tasks may reflect improvements based on the levodopa/benserazide treatment.

“[W]e show that the performance of a simple handwriting paradigm in combination with resembling instrumental tasks may reflect an improvement of the velocity of movement execution following the administration of soluble L-dopa/benserazide in previously treated PD [Parkinson’s disease] patients,” the researchers concluded.

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