METHOD FOR DIFFERENTIAL DIAGNOSIS OF FUNCTIONAL HAND TREMOR AND HAND TREMOR IN ORGANIC PATHOLOGY OF NERVOUS SYSTEM Russian patent published in 2024 - IPC A61H5/00 

FIELD: medicine.

SUBSTANCE: invention relates to neurology and can be used for differential diagnosis of functional hand tremor and hand tremor in organic pathology of nervous system. Diagnostics is carried out by electrophysiological examination, for which two-channel accelerometry is used by applying and fixation of accelerometers on middle phalanx of index fingers of both hands and four-channel surface electromyography by placing surface gel electrodes on pre-cleaned places on both hands in projection of muscles of flexors and extensors of fingers. One fingers are fixed in a projection of a complex of flexor muscles of the wrist and fingers at the point of maximum compaction in the medial part of the anterior surface of the upper one-third of the forearm when the wrist and fingers are bent against external resistance. Active electrode – cathode, is fixed on point of maximum compaction. Reference electrode – anode is fixed 4–5 cm distally along the surface of the finger flexor. Other surface gel electrodes are fixed in a projection of a complex of muscles of the extensor muscles of the fingers and a extensor carpi radialis brevis at the point of maximum compaction in the lateral part of the posterior surface of the upper one-third of the forearm when the wrist and fingers are extended against external resistance. Active electrode – cathode, is fixed on point of maximum compaction. Reference electrode – anode is fixed at 4-5 cm distal along the finger extensor. Contacts from the fixed electrodes are connected to the amplifier of the electromyographic apparatus Natus Viking EDX (USA) in the following sequence: right hand accelerometer, right finger extensors, right finger flexors, left hand accelerometer, left finger extensors, left finger flexors. Thereafter, 30-second tremorogram is recorded in a position with arms extended with palms down in the absence and in the presence of a cognitive load (CL) in the form of subtraction by 13 out of 100 and electromyographic activity with a frequency within the determined width of the frequency peak. Obtained records are exported from the pre-installed Tremor Analysis software in the form of a text file with a sampling rate of 1,000 Hz, which is loaded into the open software Tremoroton, and on the “Frequency domain” tab, the hand most involved in the tremor is identified by the width of the frequency peak according to accelerometry data with CL and without CL. Peak width is defined as the difference between the minimum and maximum frequencies at an intensity level of 40–50 % of the maximum frequency with cognitive load. Further, the “Specrtogram” tab is used to estimate the width of the oscillation frequency band according to the accelerometry of the hand most involved in the tremor with CL and the presence of pauses during 30-second recording of the tremorogram according to the accelerometry of the hand most involved in the tremor. If the width of the frequency peak of the hand most involved in the tremor is more than 0.5 Hz according to the accelerometry data, which increases with the underlying cognitive load, the width of the frequency band of the hand most involved in the tremor on spectrogram is 3 Hz or more and the presence of pauses during 30-second recording of the tremorogram according to the accelerometry of the hand most involved in the tremor with a total duration of 3 seconds or more, the functional genesis of the hand tremor is diagnosed. In case of presence of frequency peak of hand most involved in tremor according to accelerometry data with width of 0.5 Hz or less, which remains unchanged or decreases against background of cognitive load, frequency band width of the hand most involved in the tremor on the spectrogram is less than 3 Hz, absence of pauses or presence of pauses during 30-second recording of the tremorogram according to the accelerometry of the hand most involved in the tremor with total duration of less than 3 seconds, the hand tremor is determined in the organic pathology of the nervous system.

EFFECT: wider range of technical means for differential diagnosis of functional tremor of hands and tremor of hands in organic pathology of nervous system with high reliability.

1 cl, 12 dwg, 2 tbl