Feasibility of Brachial Occlusion Technique for Beat-to-Beat Pulse Wave Analysis.

Czech physiologist Penaz tried to overcome limitations of invasive pulse-contour methods (PCM) in clinical applications by a non-invasive method (finger mounted BP cuff) for continuous arterial waveform detection and beat-to-beat analysis. This discovery resulted in significant interest in human physiology and non-invasive examination of hemodynamic parameters, however has limitations because of the distal BP recording using a volume-clamp method. Thus, we propose a validation of beat-to-beat signal analysis acquired by novel a brachial occlusion-cuff (suprasystolic) principle and signal obtained from Finapres during a forced expiratory effort against an obstructed airway (Valsalva maneuver). Twelve healthy adult subjects [2 females, age = (27.2 ± 5.1) years] were in the upright siting position, breathe through the mouthpiece (simultaneously acquisition by brachial blood pressure monitor and Finapres) and at a defined time were asked to generate positive mouth pressure for 20 s (Valsalva). For the purpose of signal analysis, we proposed parameter a "Occlusion Cuff Index" (OCCI). The assumption about similarities between measured signals (suprasystolic brachial pulse waves amplitudes and Finapres's MAP) were proved by averaged Pearson's correlation coefficient (r- = 0.60, p < 0.001). The averaged Pearson's correlation coefficient for the comparative analysis of OCCI between methods was r- = 0.88, p < 0.001. The average percent change of OCCI during maneuver: 8% increase, 19% decrease and percent change of max/min ratio is 35%. The investigation of brachial pulse waves measured by novel brachial blood pressure monitor shows positive correlation with Finapres and the parameter OCCI shows promise as an index, which could describe changes during beat-to-beat cardiac cycles.

Unusual Set of Adverse Effects During Right-Unilateral Ultrabrief Electroconvulsive Therapy Led to the Discovery of a Brain Tumor: A Case Report.

We describe a case of a right-handed, 42-year-old, Caucasian female patient who manifested a set of unusual adverse effects during maintenance ultrabrief right-unilateral electroconvulsive therapy (ECT)-generalized myoclonic secondary seizure with lateralization nonresponsive to repeated intravenous diazepam application, deviation of the tongue and the head to the left, ping-pong gaze with nystagmoid jerks, postictal hypoactive confusion state lasting 15 minutes (with a total time to recovery 30 minutes), and likely Todd's paralysis after the procedure (subsided within 24 hours). These adverse effects led to a thorough clinical investigation and eventually the discovery of a brain tumor. In the article, we hypothesize about the possible interaction between the intracranial mass and ECT and provide a literature overview on the topic. Cases like this are likely underreported, and although several studies demonstrate that ECT can be applied safely to patients with an intracranial mass, this report demonstrates that brain tumor can interfere with ECT in an unpredictable way and have severe consequences (eg, unresponsiveness to diazepam when attempting to halt the seizure as our patient). Unusual symptoms after ECT, albeit reversible, such as in this case report, should be followed by a thorough neurological check-up to exclude any underlying organic pathology.

Noninvasive Assessment of Aortic Pulse Wave Velocity by the Brachial Occlusion-Cuff Technique: Comparative Study.

Cardiovascular diseases are one of most frequent cause of morbidity and mortality in the world. There is an emerging need for integrated, non-invasive, and easy-to-use clinical tools to assess accurately cardiovascular system primarily in the preventative medicine. We present a novel design for a non-invasive pulse wave velocity (PWV) assessment method integrated in a single brachial blood pressure monitor allowing for up to 100 times more sensitive recording of the pressure pulsations based on a brachial occlusion-cuff (suprasystolic) principle. The monitor prototype with built-in proprietary method was validated with a gold standard reference technique SphygmoCor VX device. The blood pressure and PWV were assessed on twenty-five healthy individuals (9 women, age (37 ± 13) years) in a supine position at rest by a brachial cuff blood pressure monitor prototype, and immediately re-tested using a gold standard method. PWV using our BP monitor was (6.67 ± 0.96) m/s compared to PWV determined by SphygmoCor VX (6.15 ± 1.01) m/s. The correlation between methods using a Pearson's correlation coefficient was r = 0.88 (p < 0.001). The study demonstrates the feasibility of using a single brachial cuff build-in technique for the assessment of the arterial stiffness from a single ambulatory blood pressure assessment.

Emotional arousal in patients with functional movement disorders: A pupillometry study.

OBJECTIVE: Pathophysiology explanations for functional movement disorders often assume a role for emotional hyperarousal. Pupillometry is a validated method for evaluation of emotional arousal by detecting changes in pupil size in response to emotional stimuli. In a case-control study design, we aimed to study objective and subjective emotional arousal using pupillometry and affective ratings. To assess attentional engagement by affective stimuli, we used videooculographic tracking of eye movement patterns (scanpath). METHODS: Twenty-five female patients with functional movement disorders (mean age: 40.9 [SD 12.7] years) and 23 age matched healthy female controls participated in the study. Using infrared high-resolution eye-tracker, both pupil size and eye movement pattern in response to emotionally charged erotic, adventure, threat, victim, and neutral pictures were recorded along with subjective ratings of emotional valence and arousal of the presented pictures. RESULTS: A between-group comparison showed significantly smaller pupil dilation to adventure stimuli compared to neutral stimuli in patients compared to controls (P < 0.004, bootstrap, uncorr., adj. η2 = 0.00). No significant difference in pupillary response to other stimuli and scanpath parameters was found between the groups. Patients rated significantly lower emotional arousal to erotic pictures than controls (P < 0.001, bootstrap, uncorr., adj. η2 = 0.09). CONCLUSION: This study did not find evidence of autonomous or subjective emotional hyperarousal. The mismatch between objective autonomic measures and subjective arousal ratings in patients is of pathophysiological interest and in line with recent findings of impaired interoception in functional movement disorders.

Long-term effect of transcranial direct current stimulation in the treatment of chronic tinnitus: A randomized, placebo-controlled trial.

Introduction: Tinnitus is an intrusive and chronic illness affecting a significant portion of the population, decreasing affected individuals' quality of life and socioeconomic functioning. Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulatory method utilizing weak electrical currents to elicit short and long-term central nervous system changes. Several studies have proven its effect on tinnitus. We aimed to broaden the knowledge and provide data on the effect and its retention. Methods: In the randomized, double-blinded, sham-controlled trial, 39 patients (active n = 19, sham n = 20) underwent bifrontal tDCS (anode over right dorsolateral prefrontal cortex (DLPFC), cathode left DLPFC, current of 1.5 mA, 20 min, 6 sessions in 2 weeks). Tinnitus Functional Index (TFI), Iowa Tinnitus Handicap Questionnaire (ITHQ), Beck Anxiety Inventory (BAI), Zung Self-Rating Depression Scale (SDS), and WHO-Quality of Life-BREF were employed in 4 evaluation points, including the follow-ups of 6 weeks and 6 months. Results: We reached a delayed, significant long-term improvement (p < 0.05) in auditory difficulties associated with tinnitus and noticed it even after 6 months compared to placebo. We also reached a short-term, negative effect in the psychological domain of WHO-Quality of Life-BREF (p < 0.05). Not all subdomains of TFI and ITHQ reached statistical significance during the data analysis, even though specific positive trends were noticed. Conclusion: We proved partial, positive, long-term effects of tDCS on tinnitus and short-term, negative, transient effect on a specific aspect of the general quality of life. We expanded upon the results of previous trials and provided data concerning the longevity and the precise effect of multiple sessions, bifrontal DLPFC tDCS. Our sample size (n = 39) was limited, which might have contributed to the lesser statistical power of the analyzed items. Clinical trial registration: [www.ClinicalTrials.gov], identifier [NCT05437185].

Non-invasive assessment of arterial pulsatility in patients with continuous-flow left ventricular assist devices.

INTRODUCTION: Long-term use of continuous-flow left ventricular assist devices may have negative consequences for autonomic, cardiovascular and gastrointestinal function. It has thus been suggested that non-invasive monitoring of arterial pulsatility in patients with a left ventricular assist device is highly important for ensuring patient safety and longevity. We have developed a novel, semi-automated frequency-domain-based index of arterial pulsatility that is obtained during suprasystolic occlusions of the upper arm: the 'cuff pulsatility index'. PURPOSE: The purpose of this study was to evaluate the relationship between the cuff pulsatility index and invasively determined arterial pulsatility in patients with a left ventricular assist device. METHODS: Twenty-three patients with a left ventricular assist device with end-stage heart failure (six females: age = 65 ± 9 years; body mass index = 30.5 ± 3.7 kg m-2) were recruited for this study. Suprasystolic occlusions were performed on the upper arm of the patient's dominant side, from which the cuff pressure waveform was obtained. Arterial blood pressure was obtained from the radial artery on the contralateral arm. Measurements were obtained in triplicate. The relationship between the cuff pressure and arterial blood pressure waveforms was assessed in the frequency-domain using coherence analysis. A mixed-effects approach was used to assess the relationship between cuff pulsatility index and invasively determined arterial pulsatility (i.e. pulse pressure). RESULTS: The cuff pressure and arterial blood pressure waveforms demonstrated a high coherence up to the fifth harmonic of the cardiac frequency (heart rate). The cuff pulsatility index accurately tracked changes in arterial pulse pressure within a given patient across repeated measurements. CONCLUSIONS: The cuff pulsatility index shows promise as a non-invasive index for monitoring residual arterial pulsatility in patients with a left ventricular assist device across time.

Author Correction: Pupil size reflects successful encoding and recall of memory in humans.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Noninvasive Blood Pressure Monitor Designed for Patients With Heart Failure Supported with Continuous-Flow Left Ventricular Assist Devices.

The gold standard for noninvasive blood pressure (BP) measurement, the Doppler technique, does not provide systolic blood pressure (SBP) and diastolic blood pressure (DBP) and may limit therapy outcomes. To improve patient care, we tested specifically designed experimental BP (ExpBP) monitor and the Doppler technique by comparing noninvasive measures to the intraarterial (I-A) BP in 31 patients with end-stage heart failure (4 females) 2.6 ± 3.4 days post-LVAD implantation (20 HeartMate II and 11 HeartWare). Bland-Altman plots revealed that the ExpBP monitor overestimated mean arterial pressure (MAP) by 1.2 (4.8) mm Hg (mean difference [standard deviation]), whereas the Doppler by 6.7 (5.8) mm Hg. The ExpBP SBP was overestimated by 0.8 (6.1) mm Hg and DBP by 1.9 (5.3) mm Hg compared with the respective I-A pressures. Both techniques achieved similar measurement reliability. In the measurement "success rate" expressed as a frequency (percent) of readable BP values per measurement attempts, Doppler accomplished 100% vs. 97%, 97%, and 94% of successful detections of MAP, SBP, and DBP provided by the ExpBP monitor. The ExpBP monitor demonstrated higher accuracy in the MAP assessment than the Doppler in addition to providing SBP and DBP in majority of subjects. Improved BP control may help to mitigate related neurologic adverse event rates.

Pupil size reflects successful encoding and recall of memory in humans.

Pupil responses are known to indicate brain processes involved in perception, attention and decision-making. They can provide an accessible biomarker of human memory performance and cognitive states in general. Here we investigated changes in the pupil size during encoding and recall of word lists. Consistent patterns in the pupil response were found across and within distinct phases of the free recall task. The pupil was most constricted in the initial fixation phase and was gradually more dilated through the subsequent encoding, distractor and recall phases of the task, as the word items were maintained in memory. Within the final recall phase, retrieving memory for individual words was associated with pupil dilation in absence of visual stimulation. Words that were successfully recalled showed significant differences in pupil response during their encoding compared to those that were forgotten - the pupil was more constricted before and more dilated after the onset of word presentation. Our results suggest pupil size as a potential biomarker for probing and modulation of memory processing.

Differences in mean arterial pressure of young and elderly people measured by oscilometry during inflation and deflation of the arm cuff.

Systemic arterial blood pressure (BP) is one of the most important parameters of the cardiovascular system. An oscillometric NIBP monitor was specifically designed to measure oscillometric pulsations and mean arterial pressure (MAP) during inflation and deflation of the cuff. Nineteen healthy young (age 23.1±1.7 years; mean±SD) and 35 elderly (83.9±7.9 years; mean±SD) subjects were studied. Differential analysis of MAP during inflation and deflation show mean |ΔMAP|=2.9±2.6 mm Hg in the young group (mean±SD) and |ΔMAP|=6.3±5.2 mm Hg for seniors (mean±SD). There was a significant difference (p<0.05) in means of |ΔMAP| measured during cuff inflation and cuff deflation between both groups. In about 50% of elderly subjects |ΔMAP| was higher than 5 mm Hg. Potential clinical relevance of the method needs to be further evaluated.

Noninvasive assessment of cardiac output by brachial occlusion-cuff technique: comparison with the open-circuit acetylene washin method.

Cardiac output (CO) assessment as a basic hemodynamic parameter has been of interest in exercise physiology, cardiology, and anesthesiology. Noninvasive techniques available are technically challenging, and thus difficult to use outside of a clinical or laboratory setting. We propose a novel method of noninvasive CO assessment using a single, upper-arm cuff. The method uses the arterial pressure pulse wave signal acquired from the brachial artery during 20-s intervals of suprasystolic occlusion. This method was evaluated in a cohort of 12 healthy individuals (age, 27.7 ± 5.4 yr, 50% men) and compared with an established method for noninvasive CO assessment, the open-circuit acetylene method (OpCirc) at rest, and during low- to moderate-intensity exercise. CO increased from rest to exercise (rest, 7.4 ± 0.8 vs. 7.2 ± 0.8; low, 9.8 ± 1.8 vs. 9.9 ± 2.0; moderate, 14.1 ± 2.8 vs. 14.8 ± 3.2 l/min) as assessed by the cuff-occlusion and OpCirc techniques, respectively. The average error of experimental technique compared with OpCirc was -0.25 ± 1.02 l/min, Pearson's correlation coefficient of 0.96 (rest + exercise), and 0.21 ± 0.42 l/min with Pearson's correlation coefficient of 0.87 (rest only). Bland-Altman analysis demonstrated good agreement between methods (within 95% boundaries); the reproducibility coefficient (RPC) = 0.84 l/min with R2 = 0.75 at rest and RPC = 2 l/min with R2 = 0.92 at rest and during exercise, respectively. In comparison with an established method to quantify CO, the cuff-occlusion method provides similar measures at rest and with light to moderate exercise. Thus, we believe this method has the potential to be used as a new, noninvasive method for assessing CO during exercise.

Comparative study of non-invasive blood pressure measurement methods in elderly people.

Results obtained by the modern automatic blood pressure (BP) monitors using oscillometric method [5] are highly dependent on conditions of cardiovascular system of the monitored person. Especially, with people who suffer from cardiovascular diseases (e.g. atherosclerosis) the resulting values differ significantly from those measured by the traditional auscultation method. A reasonable solution for improvement of quality of oscillometric method could be a sophisticated intelligent BP measuring system which applies for evaluation of BP more complex approach taking into account the monitored person's condition of patient cardiovascular system (CS) i.e. the hemodynamic parameters of CS (e.g. heart rate, stroke volume, total peripheral resistance, systemic arterial compliance, pulse wave velocity, augmentation index etc.). Such a system has to be based on appropriate models of the considered diseases which are validated on real life data. For that purpose, we have started to build a database of real-life oscillometric pulsations waveforms (OPW) complemented by the values of "auscultation" blood pressure measurements and additional relevant information about the considered patients (age, sex, etc.) as well as their diagnosis. This data collection requires a special HW device for measurement of the OPW--we have developed such a device and it has been validated in Czech Certified Metrological Centre. Our OPW monitor is connected through the T-pieces and tubes to the cuff, mercury sphygmomanometer and automatic "oscillometric" blood pressure monitor.