Exploring Ultra-short Heart Rate Variability Metrics in Patients with Diabetes Mellitus: A Reliability Analysis.

Objectives: Ultra-short heart rate variability (HRV) metrics represent autonomic tone parameters derived using small epochs of interbeat interval data. These measures have risen in popularity with the advent of wearable devices that can capture interbeat interval data using electrocardiography (ECG) or photoplethysmography. Autonomic neuropathy in diabetes mellitus (DM) is well established, wherein 5-min HRV is conventionally used. Ultra-short measures have the potential to serve as markers of reduced autonomic tone in this patient population. Methods: Data of patients with Type I and Type II DM who had presented to our laboratory for autonomic neuropathy assessment were chosen for analysis. One-minute and 2-min epochs were chosen from 5 min of ECG data using standard software. Time domain, frequency domain, and nonlinear measures were computed from 1 to 2 min epochs, and reliability was compared with measures derived from 5-min HRV using intraclass correlation coefficients (ICCs). Results: Data of 131 subjects (79 males, 52 females; mean age = 53.3 ± 12.16 years) were analyzed. All ultra-short HRV measures derived from 1 min to 2 min data showed good to excellent reliability (median ICC values ranging from 0.83 to 0.94) when compared with 5-min metrics. The notable exception was very low frequency (VLF) power, which showed poor reliability (median ICC = 0.43). Conclusions: Ultra-short HRV metrics derived from 1 to 2 min epochs of ECG data can be reliably used as predictors of autonomic tone in patients with DM. VLF power is poorly reproducible in these small epochs, probably due to variability in respiratory rates. Our findings have implications for ultra-short HRV estimation using short epochs of ECG data.

Font Matters: Deciphering the Impact of Font Types on Attention and Working Memory.

Introduction Various types of fonts such as serif, sans serif, and script are used during writing and reading, which can affect the reader's attention and working memory, though there is only a subtle difference at the end of the letter. The study aimed to see the effect of font type on working memory and attention. Methods The study included healthy male adults between 18 and 40 years of age. After taking all the necessary precautions, a letter cancellation test and 2-back task in serif, sans serif, and script font types were done to evaluate subjects' attention and working memory. Results A total of 30 subjects participated in the study. The letter cancellation task (LCT) was statistically significant (P<0.05) between the three groups, where the time taken to complete the task was the shortest for serif fonts, indicating heightened attention to serif fonts. However, the accuracy of the N-back test did not show statistically significant differences (P>0.05) among the three font groups, indicating no significant change in working memory. Conclusion The type of font used can impact the reader's attention, with Times New Roman font demonstrating greater attention, particularly in the context of the letter cancellation task.

Attentional Correlates of Colored Lights: Considerations for Cognitive Testing.

Attention, an important index of cognitive function, can be affected amidst colored lights. This work investigated the effects of colored lights on the performance in attention task. Participants (N = 42) performed in one, two, and three letter cancellation task (LCT) during four lighting conditions. The order of LCT and the colored light sessions were randomized. The performance in LCT was evaluated through % accuracy, % omission, and % error. A repeated measures ANOVA showed a statistically significant difference in % accuracy in one LCT (F(2.46, 100.8) = 24.45, p < 0.001), two LCT (F(2.57, 105.4) = 20.53, p < 0.001), and three LCT (F(2.66, 109.22) = 17.96, p < 0.001) among the four colored lights. In addition, % omission revealed a statistically significant difference in one LCT (F(2.46, 100.8) = 24.43, p < 0.001), two LCT (F(2.57, 105.4) = 20.57, p < 0.001), and three LCT (F(2.66, 109.16) = 18.21, p < 0.001) among the four lights. There was no statistically significant difference in % error in one LCT (F(2.05, 84.1) = 1.23, p = 0.3), two LCT (F(2.66, 109.06) = 0.62, p = 0.971), three LCT (F(2.62, 107.53) = 0.97, p = 0.4) among the four lighting conditions. Colored lights affect attention-related cognitive processing. The attentional correlates of white and red lights are more compared to green, and blue lights. Lighting condition should be an important consideration for cognitive testing, for designing workspaces, educational settings, and other environments where attention plays a crucial role.

Use of Multimodality Intraoperative Neuromonitoring in Tethered Cord Syndrome - Experience from a Tertiary Care Center.

Detethering of the spinal cord is done in nearly all cases of tethered cord syndrome (TCS), which can damage nerve roots, and hence, there is a need to identify filum terminale during surgery. Multimodality intraoperative neuromonitoring (IONM) may be useful in this regard to prevent postoperative morbidity. Twenty-six patients (13 males and 13 females, age range: one year to 56 years) with TCS were recruited for the study. Triggered electromyography (t-EMG), transcranial motor evoked potential (TcMEP) and free-running electromyography (f-EMG) were used in the study on a case-to-case basis. Warning criteria were followed according to the standard guidelines. Nerve roots and filum terminale were successfully identified and detethered in all cases. There was no new postoperative deficit seen. Transcranial motor evoked potentials did not change during surgery and no new limb weakness was seen in any of the investigated cases. Triggered EMG successfully helps in identifying nerve roots and filum terminale, while TcMEP is a good prognostic indicator of motor viability. Multimodality IONM use during tethered cord surgery should be encouraged to prevent postoperative deficits.