Table 1
Clinical characteristics of patients with tacrolimus induced tremor.
| PATIENT 1 | PATIENT 2 | PATIENT 3 | PATIENT 4 | |
|---|---|---|---|---|
| Age in years | 63 | 57 | 73 | 72 |
| Sex | male | female | male | male |
| Diagnosis | ESRD secondary to type II diabetes | ESRD secondary to ADPKD | ESRD secondary to FSGS | ESRD secondary to glomerulonephritis |
| Disease duration | 6 years | 8 months | 15 years | 10 years |
| Tacrolimus Dose in mg/day | 8 | 4 | 2 | 3.5 |
| Tacrolimus Level (nG/mL) | 5.4 | 11 | 5.1 | 3.3 |
| Onset time for tremor after tacrolimus | one week | few weeks | three weeks | two weeks |
| Tremor Duration | 4 months | 3 months | 11 years | 10 years |
| Functional activity most important | writing | jewelry crafting | writing | eating |
| Rating of task | ||||
| speaking | 0 | 0 | 0 | 0 |
| feeding | 2 | 2 | 2 | 2 |
| bringing liquids to mouth | 2 | 3 | 2 | 2 |
| hygiene | 1 | 3 | 2 | 1 |
| dressing | 1 | 2 | 2 | 1 |
| writing | 2 | 2 | 2 | 2 |
| working | 2 | 4 | 2 | 1 |
| Activities of daily living total score | 10 | 16 | 12 | 9 |
| Physical examination | ||||
| rest tremor score | 0 | 0 | 1 | 0 |
| posture tremor score | 1 | 1 | 3 | 1 |
| action/kinetic tremor score | 2 | 1 | 2 | 2 |
| dot approximation task score | 1 | 1.5 | 2 | 2 |
| spiral drawing task score (worst) | 1 | 0 | 2 | 1 |
| line drawing score | 0 | 0 | 1 | 1 |
| handwriting score | 1 | 0 | 2 | 1 |
| TRS Total Score | 20 | 24 | 34 | 21 |
[i] ESRD: End stage renal disease.
ADPKD: Autosomal Dominant Polycystic Kidney Disease.
FSGS: Focal segmental glomerulosclerosis.
Figure 1
A. Placement of accelerometer (Trigno sensor) on the dorsum of the hand, sensor placed 1 cm distance proximal to the third metacarpophalangeal joint. The patient maintained a steady extended posture. B. Reusable Icepack from Patterson Medical was used. C. There were two icepacks placed in two pillowcases that were wrapped around the forearm and the hand. Tremor was recorded immediately after cooling while the patient maintained a steady extended posture and the accelerometer placed on the dorsum of the hand.
Figure 2
A. Power spectrum analysis of accelerometer recording from patient 3. Peak frequency and harmonic frequencies are depicted. The unit for amplitude is g2/Hz. The frequency unit is hertz. Half-peak bandwidth shown in the figure was calculated as the width of the spectral peak at one-half the peak amplitude in the power spectrum. High-frequency harmonic frequencies are shown B. Accelerometer tracing reveals that the oscillations were rhythmic but the waveforms were not necessarily sinusoidal. C. EMG bursts recorded from extensor carpi radialis muscle of patient 3. D. EMG recording of extensor carpi radialis muscle revealing 75–85 ms as the average duration of bursts.
Figure 3
Plot revealing time-frequency spectrogram of tremor power for individual patients recorded with accelerometer and EMG. The fundamental tremor frequency remained stable across time.
Figure 4
Power spectrum analysis of accelerometer signal recordings performed after limb cooling for each participant.
Supplemental Videos
Postural component recordings for tacrolimus induced tremor. Videos were recorded during the postural elevation of arms task. Video segments for the individual participants reveal distal bilateral hand tremors. The tremor was mainly symmetric, involving the metacarpophalangeal and interphalangeal joints. Patient 3 had a slightly jerky tremor in the right hand during the arm elevation task however had a rhythmic tremor during kinetic tasks (not shown in the video).
Table 2
Physiological findings obtained from accelerometer-based recordings.
| PATIENT 1 | PATIENT 2 | PATIENT 3 | PATIENT 4 | |
|---|---|---|---|---|
| Postural tremor | ||||
| frequency in Hz | 5.5 | 5.5 | 5 | 6 |
| amplitude in g2/Hz (mean ± SD) | 0.006 ± 0.001 | 0.005 ± 0.001 | 0.04 ± 0.002 | 0.001 ± 0.001 |
| bandwidth in Hz | 0.9 | 1 | 1.5 | 1.3 |
| Effects of cooling | ||||
| frequency in Hz | 5.5 | 4.5 | 4 | 6 |
| amplitude in g2/Hz (mean ± SD) | 0.0001 ± 0.0001 | 0.0001 ± 0.0002 | 0.0002 ± 0.0002 | 0.00001 ± 0.00002 |
| bandwidth in Hz | 2.1 | 1.5 | 1.8 | 1.6 |
[i] Mean of fundamental and harmonic power with standard deviation (SD) is provided.