Idioventricular low frequency oscillation in QT interval responds univocally to RR confusing kinds of mental stress.

Seventeen male subjects, aged nineteen to twenty, went through a protocol including, while supine, relaxation at rest (10 min) and mental stress (MS) by a Kraepelin (arithmetic) test (5 min), as part of a larger study. With a polygraphic analog recording set-up we also collected a 1 ms - digital facsimile of a lead II-like thoracic ECG with maximum T-wave (Codas, Dataq Instr). Twenty-three stress responses were assigned to three classes according to known cardiotacho-, plethysmo-, and pneumo-graphic marks of "concentrated attention mainly," "emotion," or still "high emotion." During each setting the most stationary 3 min RR epoch in cardiotachogram was selected for joint RR & QT beat-by-beat variability study. RR and QT intervals were detected using a published algorithm. Conventional RR and QT Fourier autospectra were computed, while using RR*QT mean square coherence spectrum we detached the RR-independent, idioventricular (IV) fraction of QT low frequency (LF: 0.04-0.15 Hz) power of variability (IV QT-LF). IV QT-LF responded consistently to varieties of mental stress that confuse RR-LF or let QT-LF unchanged, best witnessing the cortically-issued ventricular adrenergic strain. Indeed, while emotion propels the same way all spectral variables above, concentrated attention increased (Wilcoxon) significantly IV QT-LF only (0.54-0.80 ms2) and decreased RR-LF (715-463 ms2). Findings hold promise of a non-invasive, high resolution Holter based monitoring of sympathetic status of myocardium, robust vis-à-vis of confusion caused by the autonomic interplay at sino-atrial node.     

Changes in the EEG frequency spectrum in various phases of mental stress

To obtain evidence about the relationship between spontaneous EEG activity and mental activity, an experiment was designed and executed with EEG recordings during a concept-learning task. We varied task performance (self-paced vs. machine-paced) and distinguished different stages of information processing during task performance. Using factor analysis calculated on all spectral coefficients, we found two orthogonal variables in the clinical alpha band. Alpha 2 power (10.5-12 Hz) seems to reflect the overall processing demands imposed on the individuals. Furthermore, there are different EEG frequency patterns during perceptual-central- compared with response-related processing as well as during processing of positive vs. negative feedback. The results suggest using (1) conservative procedures in hypothesis testing and (2) procedures to reduce between subject variability (a posteriori defined frequency variables, relative power values, scaling of reaction values) in further studies relating EEG activity to mental activity during task performance.     

Age-related differences in cardiovascular reactions to mental stress tests in women

Tested 84 healthy, sedentary women in the laboratory during performance of difficult and easy problem-solving tasks. They were divided into three age groups: 19 to 32 years, 33 to 43 years, and 44 to 60 years (n = 28 women per group). Baseline systolic blood pressure (SBP) and diastolic blood pressure increased with age, whereas skin conductance level was lower in older women. In addition, initial SBP reactions to tasks were positively related to age, even after controlling for baseline blood pressure, aerobic fitness, and Framingham Type A Scale behavior scores. There were no differences in heart rate (HR) or "additional" HR reactions, so the anticipated decline in cardiac sympathetic response with age was not observed. The mechanisms underlying age-related reactions to mental stress are discussed.     

QT & RR variability spots the earliest autonomic deregulation in diabetes. Fading of vagal sino-atrial drive but not of sympathetic ventricular responsiveness to life challenges.

27 consecutive insulin-dependent diabetic patients (pts), under 50 years, with blood glucose controlled within normal limits and no significant or multiple cardiovascular/neurological complications in the lights of clinical tests, went through a protocol as follows: laiddown at relaxed rest for 10 min, then stood-up quietly for 7 min, and finally experienced a stress-interview for 10 min while supine. A thoracic ECG lead was digitized at I ms (Codas, Dataq Instr.), RR and QT intervals were software-detected, resampled at 500 ms, and Fourier-transformed over 3 min epochs to get auto-or cross-spectra. RR-by-QT mean square coherence detached the RR-independent fraction of QT low fequency (LF) spectral power, called idioventricular QT-LF. We detected autonomic impairment of three types (discriminant score = 92.31%), presumably differentiated upon the locus of lesion, using RR's basal variance and mean RR shortening when standing as follows: (I) RR shortening > 200 ms in 10 pts; (II) normal RR shortening but no RR variance in 4 pts; (III) stiff RR around 600 ms and no RR variance in 2 pts. The above pts have been excluded from further analysis. The remaining 11 pts with no such impairments (5M and 6F, 36.4 y +/- 4.4 SD, history of 6.0 y +/- 5.2) have been compared with 11 normal subjects in an age and gender-paired control group in two steps. Step 1: Preliminary MANOVA/ANOVA showed significant effects on the ensemble of spectral variables of every single factor (status: normal or patient group; intervention; gender) with no significant factor interactions. Significant effects of intervention or status on main RR spectral variables and on a few QT spectral variables were also documented. Step 2: Non-parametric tests showed that diabetics had (mildly to moderately) shorter mean RR, while their RR-LF was always significantly lower than those found in normals--a difference propagated to QT-LF but not to idioventricular QT-LF. In the intra-group there were similar responses to interventions except stress with respect to mean RR. Consistent reduction in RR-LF under moderate or no change in mean RR suggests vagal down- regulation that, judging by idioventricular QT-LF showing, goes perhaps before a similar process with sympathetic control of ventricles. This phase delay may introduce an early arrhythmic risk worth dealing with in secondary prevention.     

Psychophysiological reactivity to mental arithmetic stress in black and white normotensive men

Racial differences in physiological responses to a behavioral stressor were examined. Thirty-four Black and 42 White male normotensives 34 to 55 years old (mean age = 43.01 years) performed a mental arithmetic task while blood pressure, heart rate, and skin conductance were recorded. Compared to Whites, Blacks had significantly higher baseline diastolic blood pressure (77.93 mm Hg vs. 73.11 mm Hg) and lower skin conductance levels (11.08 microS vs. 12.25 microS). These effects persisted during performance of the mental arithmetic task. However, when baseline differences were covaried, there were no significant physiological effects associated with the task. Analysis of changes in response levels from baseline revealed a nonsignificant trend for Whites to show greater increases in systolic blood pressure than Blacks. There were no significant race or family history effects. Further, task performance did not influence the outcome. Failure to demonstrate greater cardiovascular reactivity in Blacks and all men with a positive family history of hypertension is discussed with regard to possible "survivor effects" and methodologic limitations.     

Mental stress enhances the sympathetic fraction of QT variability in an RR-independent way

In 10 healthy male volunteers aged 19–20, spectral power of the beat-by-beat QT interval was measured at the Traube-Herring-Mayer (THM) band (0.05 to 0.15 Hz) when the subject was at rest and during atrial pacing. After resting in dorsal decubitus for 10 minutes, right atrial pacing was performed at a slight elevation above sinus rhythm as well as at 100 or at 110 beats per minute for 7 minutes each. In addition, during pacing at 100 or 110 bpm, the subject was required to perform a Kraepelin Arithmetic test. There was a statistically significant increase in QT spectral power at the THM band, while heart rate was maintained unchanged during the periods of mental stress versus rest. This experiment confirms the potential independence of the QT interval from heart rate and suggests that THM fraction of QT spectral power has a double subordination: during relaxed rest it follows mostly RR-fluctuation; during stress an RR-independent contribution is added, which presumably reflects the supra-normal sympathetic drive on the ventricles.     

Changes in limb stiffness under conditions of mental stress

In 2 experiments, the effects of mental stress on limb stiffness were investigated. The relative contribution to arm stiffness of individual muscle activity, co-contraction, muscle reflexes, and postural adjustments were examined. In each experiment, participants (N = 24, Experiment 1; N = 16, Experiment 2) held their supinated hand under a tray that they were required to return to horizontal after it had been suddenly released. Electromyographic activity in the biceps and triceps muscles was recorded, as were elbow and wrist angles and tray displacement. In Experiment 1, mental arithmetic stress was shown to lead to decreased tray displacement (i.e., increased resistance) compared with displacements under the control, unstressed condition, as well as to increased elbow flexion before tray release. In Experiment 2, the increased resistance to perturbation caused by mental stress was found to be independent of initial elbow angle, but to vary as a function of the amount of upward force exerted before tray release. The authors conclude that stress-induced increases in limb stiffness result from changes in the initial position of the elbow, specified by its angle, together with the initial force exerted by participants to counteract the mechanical perturbations.     

Relative and absolute reinforcement frequency as determinants of choice in concurrent variable interval schedules

Rats were trained under concurrent schedules consisting of two equal variable interval component shedules providing sucrose solutions of different concentrations (0.6 M, 0.2 M; 50 μl in each case) as the reinforcers. The mean interreinforcement interval specified by the schedules was varied from 10 to 640 sec. Absolute response rate in each component was an increasing hyperbolic function of reinforcement frequency. Relative response rate and relative time allocation revealed a consistent preference for the more concentrated solution; neither measure of preference was systematically related to reinforcement frequency. The results are consistent with Baum and Rachlin's (1969) extension of the matching law, and with a derivation of the matching law from the hyperbolic relation between absolute response rate and reinforcement frequency in variable interval schedules (Herrnstein, 1970).     

Latency and frequency reports to the Necker cube illusion: effects of hypnotic susceptibility and mental arithmetic

An experiment (N = 32) was conducted to assess latency of first apparent reversal (AR) and AR frequency while observing the Necker cube illusion. Subjects who were either high in hypnotic susceptibility (susceptibles) or low in hypnotic susceptibility (resistant subjects) observed the cube either while performing or not performing mental addition problems. Susceptibles reported perceiving the first AR more quickly and a greater frequency of ARs than did resistant subjects. Also, latency of the first AR was negatively correlated with AR frequency. These results were interpreted in terms of the ability of susceptibles to allocate concentrative or selective attention in a manner that was conducive to faster performance, when faced with competing tasks.     

Lexical stress,frequency, and stress neighbourhood effects in the early stages of Italian reading development

We examined the development of stress assignment in reading Italian aloud. We investigated frequency effects as a marker of the use of item-specific lexical knowledge in assigning stress together with stress dominance and stress neighbourhood (the number of words sharing both stress and ending) as markers of distributional information regarding properties of the lexicon extracted from spoken language. We tested second- and fourth-graders in a reading-aloud experiment including high- and low-frequency words and nonwords. Results show that despite the regularity of orthography–phonology mappings in Italian and the predominant use of phonological recoding procedures, item-specific lexical knowledge is also used, even by beginning readers. The frequency effect was significant and did not increase with age, while stress errors on low-frequency words decreased with increasing grade. Stress neighbourhood increasingly affected stress assignment on nonwords with older children. Taken together, our findings show that both item-specific knowledge and general information about stress distribution are relevant in children's reading, suggesting the simultaneous use of both lexical and sublexical information. Moreover, as the reading system develops, and knowledge about the relative distribution of stress neighbourhood increases, larger grain-size units are also exploited.     

Occupational stress and mental well-being in a cohort of Black South African teachers

This study explored levels of occupational stress and mental well-being of a cohort of Black South African teachers. 200 secondary school teachers completed the Teacher Stress Inventory (TSI: Boyle, Borg, Falzon, & Baglion, 1995), General Health Questionnaire (GHQ-28: Goldberg & Hillier, 1979 Goldberg, D. P., & Hillier, V. F. (1979). A scaled version of the General Health Questionnaire. Psychological Medicine, 9, 139–145. doi: 10.1017/S0033291700021644[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and Mental Health Continuum-Short Form (MHC-SF: Keyes, 2006 Keyes, C. L. M. (2006). Mental health in adolescence: Is America's youth flourishing? American Journal of Orthopsychiatry, 76(3), 395–402. doi: 10.1037/0002-9432.76.3.395[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Correlations and Structural Equation Modelling (SEM) were used to determine the levels of occupational stress and well-being of participants, and to establish the relation between these variables. A significant majority of the teachers reported high levels of mental health (flourishing) despite high levels of teacher stress. These results show teachers’ ability to withstand and cope with stress whilst maintaining their mental health. This suggests the presence of protective factors that mediate the effect of work-related stressors and, in so doing, contribute to the teachers’ levels of resilience.     

Early tactile experience of low birth weight children: links to later mental health and social adaptation

The purpose of this study was twofold: to determine (1) the degree to which specific qualities of maternal touch may contribute to the low birth weight infant's emotional and behavioural problems as well as social adaptation, and (2) the relationship between maternal touch and a mother's other caregiving behaviour. The sample included 114 socioculturally diverse infants and their mothers who were videotaped during an infant feeding when the baby was 3 months old. This videotape was analysed to assess dimensions of mother–infant interaction, including maternal touch. Data on perinatal risk and the mother's acceptance versus rejection of the infant were also acquired. Social adaptation and emotional/behavioural problems were measured when the child was 2 years of age. Hierarchical regression analyses indicated that maternal touch accounted for 15% of the variance in the likelihood of a child having emotional/behavioural problems at age 2. Children who received more nurturing touch had significantly fewer internalizing problems (such as depression) while children receiving both more frequent touch and harsh touch had more externalizing problems (such as aggressive behaviour). Infants who were less responsive to their caregivers were especially at risk of developing aggressive/destructive behaviour as a result of frequent touch. But less responsive infants also appeared to benefit most from greater use of diverse types of maternal touch, accounting for 6% of the variance in superior adaptive behaviour at age 2. Nurturing touch was the only quality that showed even a modest relationship to other caregiving behaviour, suggesting that touch may play a distinct role in the infant's psychosocial development. Copyright © 2001 John Wiley & Sons, Ltd.     

The effect of methylphenidate on very low frequency electroencephalography oscillations in adult ADHD

Altered very low-frequency electroencephalographic (VLF-EEG) activity is an endophenotype of ADHD in children and adolescents. We investigated VLF-EEG case-control differences in adult samples and the effects of methylphenidate (MPH). A longitudinal case-control study was conducted examining the effects of MPH on VLF-EEG (.02–0.2 Hz) during a cued continuous performance task. 41 untreated adults with ADHD and 47 controls were assessed, and 21 cases followed up after MPH treatment, with a similar follow-up for 38 controls (mean follow-up = 9.4 months). Cases had enhanced frontal and parietal VLF-EEG and increased omission errors. In the whole sample, increased parietal VLF-EEG correlated with increased omission errors. After controlling for subthreshold comorbid symptoms, VLF-EEG case-control differences and treatment effects remained. Post-treatment, a time by group interaction emerged; VLF-EEG and omission errors reduced to the same level as controls, with decreased inattentive symptoms in cases. Reduced VLF-EEG following MPH treatment provides preliminary evidence that changes in VLF-EEG may relate to MPH treatment effects on ADHD symptoms; and that VLF-EEG may be an intermediate phenotype of ADHD. Further studies of the treatment effect of MPH in larger controlled studies are required to formally evaluate any causal link between MPH, VLF-EEG and ADHD symptoms.     

Violence: incidence and frequency of physical and psychological assaults affecting mental health providers in Georgia

Threats to the physical safety and psychological well-being of mental health professionals present serious problems, according to 1,131 licensed mental health professionals in the state of Georgia. The professionals included clinical social workers, marriage and family therapists, professional counselors, psychiatrists, psychologists, and social workers. From a total of 6,431 surveys sent out, 1,131 (18%) were returned. The results revealed 2.696 separate accounts of 14,120 acts of physical or psychological assaults committed by 8,292 perpetrators. The results also showed that 61% of the respondents had been victimized in violent acts of a psychological or physical nature and that 29% had feared for their lives at least once during their professional careers. These data are consistent with other research that indicates that 6 out of 10 professionals will be assaulted during their professional careers.     

Effects of cold and mental stress on finger temperature in vasospastics and normal Ss

The present experiment studied the effects of mental and cold stress on finger temperature in 9 females suffering from peripheral vasospastic attacks (Raynaud's disease; RD group) and 9 female controls. Each S sat in a 0°C cold-storage room for 15 min, on 2 separate days. In one condition they were required to count backwards aloud under threat of electric shock to the hand. Finger temperature, pulse rate and subjective ratings of stress were recorded. A significant interaction with time and mental stress was observed only for the Control group with decreased finger temperature late in the session. Pulse rate was significantly elevated during the cold + mental-stress condition compared to the cold-only condition in the Control group, but not in the RD group. Subjective ratings of stress increased for both groups during the cold + mental-stress condition, with no significant difference between the groups.