Table 2.
Comparison of heart rate and heart rate variability parameters between patients with amyotrophic lateral sclerosis and healthy controls
| Heart rate and heart rate variability parameters | Study (sub)groups | P valueb | P’ valuec | ||
|---|---|---|---|---|---|
| HCs (n = 30) | ALS-CN (n = 28) | ALS-CI (n = 37)a | |||
| Mean HR (bpm) | 70 [58–91] | 71.5 [61–93] | 76 [48–114]& | 0.035* | 0.602 |
| RRI (ms) | 853.4 [646.4–1032.9] | 813.3 [626.8–962.7] | 776.1 [669.6–1157.4]& | 0.022* | 0.947 |
| 24-h (time domain) | |||||
| SDNN (ms) | 131.5 [84–175] | 130 [82–188] | 115 [65–226]& | 0.013* | 0.069 |
| SDANN (ms) | 119.5 [71–164] | 110 [67–166] | 99 [55–174] | 0.050 | 0.096 |
| SDNN Index (ms) | 51.5 [38–73] | 51.5 [26–80] | 47 [19–94]& | 0.025* | 0.020* |
| RMSSD (ms) | 30 [17–88] | 27 [19–89] | 29 [11–97] | 0.814 | 0.747 |
| pNN50 (%) | 5.5 [0–25] | 3.5 [1–24] | 3 [0–49] | 0.369 | 0.220 |
| 24-h (frequency domain) | |||||
| TP (ms2) | 2363.2 [1444.7–5828.6] | 2402.0 [621.6–5735.7] | 1814.7 [354.3–8895.5]&,# | 0.015* | 0.001* |
| VLF power (ms2) | 1856.1 [970.6–4485.3] | 1616.1 [440.0–4091.0] | 1184.3 [245.9–7620.2]& | 0.012* | 0.002* |
| LF power (ms2) | 374.6 [187.9–1070.8] | 430.75 [110.7–1245.9] | 299.6 [77.0–1018.4] | 0.035* | < 0.001* |
| HF power (ms2) | 159.7 [50.2–447.0] | 136.7 [45.6–1103.7] | 110.5 [13.6–526.2] | 0.126 | 0.008* |
| LFnu | 69.1 [49.0–82.4] | 71.1 [12.7–87.2] | 71 [35.5–88.2] | 0.865 | 0.248 |
| HFnu | 28.3 [13.6–46.1] | 26.2 [12.0–53.9] | 25.3 [10.4–48.8] | 0.683 | 0.783 |
| LF/HF | 2.4 [1.1–6.1] | 2.8 [0.6–7.2] | 2.8 [0.7–8.5] | 0.643 | 0.516 |
ALS Amyotrophic lateral sclerosis, ALS-CI ALS patients with impaired cognition, ALS-CN ALS patients with normal cognition, HCs healthy controls, HF power high-frequency power, LF/HF ratio of LF power to HF power, LFnu LF power in normalized units, HRV heart rate variability, LF power low-frequency power, pNN50 percentage difference between adjacent NN intervals > 50 ms, RMSSD square root of mean sum-of-squares of differences between adjacent NN intervals, RRI RR-interval, SDANN standard deviation of average NN intervals in all 5-min segments, SDNN standard deviation of all normal-to-normal (NN) intervals, SDNN Index mean standard deviations of all NN intervals for each 5-min segment in a 24-h HRV recording, TP total power, VLF power very low-frequency power
aAmpersand symbol (&) indicates significant difference between the HC group and the ALS-CI subgroup; the hash symbol (#) indicates a significant difference between the ALS-CN and ALS-CI subgroups
bStatistical significance between the three groups at P value < 0.05 according to Kruskal–Wallis test
cStatistical significance between the three groups at P value < 0.05 after Blom transformation ANCOVA was used to control for age, gender, and education level
Statistical significance between the three groups at P value < 0.05