Objective: To develop a new approach to quantitative assessment of Parkinson’s tremor based on the calculation of the area of recorded wave of tremor at certain period of time. To estimate connection of a new data about tremor severity with a data of 10-point rating scale.

Background: Tremor diagnostics is currently based on the use of electromyography, optical techniques and accelerometric devices. Fourier transformation of the recorded wave of tremor is necessary to determine the severity of trembling.

Methods: 22 people with rest tremor (RT) and postural tremor (PT) at Parkinson’s disease (PD). 11 males and 11 females; age 58 years (Me), 95% CI 56,2-61,1 years; disease duration 4.4 years (Me), 95% CI: 4,09 ± 5,21 years). 11 people were with rigid-trembling form of PD and 11 – with a tremor-rigid. Severity of tremor according to 10-point rating scale was evaluated by specially trained neurologist. Accelerometric registration of RT and PT was performed by a recognized method. Original software was used for calculation of the area of registered wave of trembling. Spearman rank correlation with the definition of rank correlation coefficient (r) used.

Results: Waves of RT and PT on the screen were recorded at all patients. Intensity of RT at 10-point rating scale was 4 points (from 3 to 5 points). Intensity of RT determined by calculating of the square of recorder tremor had the following characteristics: the median – 364.2 units², 25th percentile – 143.4 units², 75th percentile – 1210.1 units². Severity of PT on a 10-point rating scale was 5 points (4 to 6 points). Severity of PT determined by calculating of the square of recorded tremor had the following characteristics: the median – 412.5 units², 25th percentile – 208.0 units², 75th percentile – 1319.2 units². A direct connection was between the values of tremor on a 10-point rating scale and the square of recorded tremor (for RT, r = 0,78; for PT, r = 0,83) (p <0.05).

Conclusions: Calculation of the square of recorded tremor may be used as an objective method of quantitative assessment of the tremor at PD. Proposed approach extends the diagnostic potential of modern accelerometric devices and needs further studies. The ability to assess the severity of tremor with multi-frequency spectrum is an initially visible advantage of this approach compared to the Fourier transformation.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/to-new-method-of-tremor-assessment/