Focused attention, heart rate deceleration, and cognitive development in preterm and full-term infants

The majority of children who are born very preterm escape major impairment, yet more subtle cognitive and attention problems are very common in this population. Previous research has linked infant focused attention during exploratory play to later cognition in children born full‐term and preterm. Infant focused attention can be indexed by sustained decreases in heart rate (HR). However there are no preterm studies that have jointly examined infant behavioral attention and concurrent HR response during exploratory play in relation to developing cognition. We recruited preterm infants free from neonatal conditions associated with major adverse outcomes, and further excluded infants with developmental delay (Bayley Mental Development Index [MDI < 70]) at 8 months corrected age (CA). During infant exploratory play at 8 months CA, focused attention and concurrent HR response were compared in 83 preterm infants (born 23–32 weeks gestational age [GA]) who escaped major impairment to 46 full‐term infants. Focused attention and HR response were then examined in relation to Bayley MDI, after adjusting for neonatal risk. MDI did not differ by group, yet full‐term infants displayed higher global focused attention ratings. Among the extremely preterm infants born <29 weeks, fewer days on mechanical ventilation, mean longest focus, and greater HR deceleration during focused attention episodes, accounted for 49% of adjusted variance in predicting concurrent MDI. There were no significant associations for later‐born gestational age (29–32 weeks) or full‐term infants. Among extremely preterm infants who escape major impairment, our findings suggest unique relationships between focused attention, HR deceleration, and developing cognition. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:383–400, 2012.     

Kinematics of reaching and implications for handedness in rhesus monkey infants

Kinematic studies of reaching in human infants using two-dimensional (2-D) and three-dimensional (3-D) recordings have complemented behavioral studies of infant handedness by providing additional evidence of early right asymmetries. Right hand reaches have been reported to be straighter and smoother than left hand reaches during the first year. Although reaching has been a popular measure of handedness in primates, there has been no systematic comparison of left and right hand reach kinematics. We investigated reaching in infant rhesus monkeys using the 2-D motion analysis software MaxTRAQ Lite+ (Innovision Systems). Linear mixed-effects models revealed that left hand reaches were smoother, but not straighter, than right hand reaches. An early left bias matches previous findings of a left hand preference for reaching in adult rhesus monkeys. Additional work using this kind of kinematic approach will extend our understanding of primate handedness beyond traditional studies measuring only frequency or bouts of hand use.     

Similar and functionally typical kinematic reaching parameters in 7- and 15-month-old in utero cocaine-exposed and unexposed infants

This study examined the effects of intrauterine cocaine exposure on the reaches of 19 exposed and 15 unexposed infants at 7 and 15 months using kinematic measures. Infants sat at a table and reached for a rattle, a toy doll, and a chair. Videotaped reaches were digitized using the Peak Performance system. Kinematic movement variables were extracted (e.g., reach duration, peak velocity, movement units, path length) and ratios computed (e.g., path length divided by number of movement units). Regardless of exposure status, reaches of older infants were faster, more direct, had fewer movement units, and covered more distance with the first movement unit. Exposed infants covered more distance per movement unit than unexposed infants, but there were no other significant differences. Reaches of exposed and unexposed infants were essentially similar. Importantly, reach parameters for these high-risk infants were similar to reach parameters for infants at lower social and biological risk.     

Auditory recognition memory in 2-month-old infants as assessed by event-related potentials

Previous studies of auditory recognition memory in sleeping newborns reported 2 event-related potential (ERP) components, P2 and negative slow wave (NSW), reflecting voice discrimination and detection of novelty, respectively. In the present study, using high-density recording arrays, ERPs were acquired from 26 2-month-old awake infants as they were presented with a familiar and unfamiliar voice (i.e., mother and stranger) with equal probability. In addition to P2 and NSW, we observed a positive slow wave (PSW) over the right temporo-parietal scalp, indicating memory updating. Our study suggests that infants appear to have the capacity to encode novel stimuli as early as 2 months of age.     

Baseline respiratory sinus arrhythmia and heart rate responses during sustained visual attention in preterm infants from 3 to 6 months of age

Three groups of preterm infants were studied longitudinally at 14, 20, and 26 weeks of age (corrected for gestational age). The groups included infants with no perinatal medical complications, those with mild respiratory problems requiring ventilatory assistance, and those with respiratory distress syndrome. Baseline heart rate and respiratory sinus arrhythmia (RSA) were recorded for 5 min, and heart rate was also recorded while the infants engaged in sustained visual attention to stimuli presented on video monitors. The heart rate response during stimulus orienting and sustained attention was smaller in those infants with respiratory distress syndrome than in the other preterm infants and in comparison with the response seen in full-term infants in previous research. Magnitude of RSA was positively correlated with the attention responses irrespective of the preterm group assignment. There was greater stability in baseline heart rate and RSA for the preterm infants than has been found with full-term infants. These data suggest that the cardiorespiratory functioning of the preterm infant indexes a stable individual difference characteristic that is correlated with heart responses during sustained attention, and heart rate attention systems may be damaged in the high-risk preterm infant.     

Comparison of postnatal development of heart rate responses to trigeminal stimulation in sleeping preterm and term infants

Autonomic dysfunction has been regarded as a possible cause of the sudden infant death syndrome (SIDS) and it has been suggested that preterm infants, who are at a greater risk of SIDS than term infants, may have immature autonomic control. Our aim was to compare the maturation of cardiac autonomic control during sleep in preterm and term infants by examining heart rate responses to arousing and non-arousing trigeminal stimuli. Preterm infants (n = 15) and term infants (n = 24) were studied longitudinally with daytime polysomnography. Air-jet stimulation of the nares was delivered in both active sleep (AS) and quiet sleep (QS), and heart rate (HR) changes recorded for both arousal and non-arousal responses. Changes in HR (DeltaHR%) were calculated as the relative differences between baseline HR (BHR) and either MaxHR (arousal) or MinHR (non-arousal). Comparisons of HR changes between sleep states and postnatal ages were made with two-way anova for repeated measures and between groups with two-way anova. The increase in HR (DeltaHR%) was greater in term than preterm infants (P < 0.05), but only at 2-3 weeks corrected postnatal age (CPA). In preterm infants, there were no differences in BHR between sleep states, whereas in term infants, BHR was higher in AS than in QS at 2-3 weeks and 2-3 months of age. The smaller DeltaHR% to arousing stimuli in preterm infants compared with term infants at 2-3 weeks suggests that cardiac sympathetic activity in preterm infants may be lower than in term infants. This mechanism may account for the increased risk for SIDS of preterm infants.     

Two-electrode telemetric instrument for infant heart rate and apnea monitoring

Infants may be at risk of life threatening episodes caused by still unknown factors. The Sudden Infant Death Syndrome (SIDS) is believed to be connected with respiration problems due to immature and developing brain breathing control, and many other factors. Currently heart rate and respiration monitoring is considered of major importance to be applied in the hospital and eventually at home. The objective is accurate detection of bradycardia (heart rate below a selected limit, usually between 80 and 100 beats/min) and apnea (cessation of breathing for more than 20 s). A telemetric instrument was developed for monitoring the heart rate and respiration by extraction of the respiration signal from the electrocardiogram QRS complex peak-to-peak amplitude. It makes use of two electrodes integrated in a transmitter module, thus avoiding use of leads and also reducing artifacts to an acceptable minimum. The receiver station can be a simple detector with apnea and bradycardia alarms, a more complicated recorder or a fully developed signal analyser.     

Signatures of emotional face processing measured by event-related potentials in 7-month-old infants

The ability to distinguish facial emotions emerges in infancy. Although this ability has been shown to emerge between 5 and 7 months of age, the literature is less clear regarding the extent to which neural correlates of perception and attention play a role in processing of specific emotions. This study's main goal was to examine this question among infants. To this end, we presented angry, fearful, and happy faces to 7-month-old infants (N = 107, 51% female) while recording event-related brain potentials. The perceptual N290 component showed a heightened response for fearful and happy relative to angry faces. Attentional processing, indexed by the P400, showed some evidence of a heightened response for fearful relative to happy and angry faces. We did not observe robust differences by emotion in the negative central (Nc) component, although trends were consistent with previous work suggesting a heightened response to negatively valenced expressions. Results suggest that perceptual (N290) and attentional (P400) processing is sensitive to emotions in faces, but these processes do not provide evidence for a fear-specific bias across components.     

Developmental change in auditory selective attention as reflected by phasic heart rate changes

Heart rate was recorded from five different groups of children (ages 7, 10, 12, 14, and 20 years) while they were performing an auditory selective attention task. The participants were instructed to count rare tone pips embedded in a series of standard tone pips presented at one (attended) ear while ignoring rare and standard stimuli presented at the other (unattended) ear. A pattern of anticipatory heart rate deceleration followed by acceleration was associated with rare tone pips at the attended ear but not with rare tone pips that should be ignored. The absence of differential sensitivity of heart rate responses to rare tone pips presented at the unattended ear was observed for all age groups. These findings were interpreted to suggest that the ability to ignore irrelevant target stimuli has reached mature levels during middle childhood. The depth of anticipatory deceleration increased until age 14, suggesting that the ability to maintain attentional set continues to develop beyond childhood.     

Differences in pulse rate and heart rate and effects on the calculation of heart rate reactivity during periods of mental stress

Heart rate and reactivity from pulse and ECG were compared over rest and mental arithmetic periods of 2-min duration each for 32 males and 50 females. Data from the two sources of heart rate were not significantly different during the rest period but did differ significantly during periods of heart rate acceleration and deceleration. Sex effects were also noted, with females having consistently higher heart rates from both sources of measurement. Calculation of heart rate reactivity via five procedures based upon the wider literature revealed significant differences between data from different sources of heart rate. Implications for assessment of heart rate reactivity to laboratory stressors are discussed, with suggestions for future research.     

Resting heart rate (HR) in women with and without premenstrual symptoms (PMS)

A sample of 64 undergraduate female students participated in the present experiment. During 3 consecutive months women answered a chart of daily report of symptoms, and finally, two groups were formed: women with premenstrual symptoms (PMS group) and women without premenstrual symptoms (NPMS group). Heart rates (HR) at rest were recorded throughout premenstrual, menstrual, postmenstrual, and ovulatory phases. In the premenstrual phase, PMS group showed significantly higher resting HR levels than NPMS group. With regard to resting HR levels across the four phases studied, significant differences within PMS group were observed. Our results are discussed from a psychophysiological point of view.     

Infant monkey heart rate: Habituation and effects of social substitutes

The heart rates of four infant monkeys that habitually clung to terry-cloth towels were measured by frequency modulation (FM) telemetry while the animals were (1) alone in an unfamiliar room, (2) in a second unfamiliar room with a towel available, and (3) in the second room without a towel. The absence of the towel in the room in which it was sometimes available produced the highest heart rate and the presence of the towel produced the lowest heart rate. Under all conditions, heart rate decreased within sessions and over repeated exposures.     

Validation of photoplethysmography as a method to detect heart rate during rest and exercise

Abstract

Despite their enhanced marketplace visibility, validity of wearable photoplethysmographic heart rate monitoring is scarce. Forty-seven healthy participants performed seven, 6-min exercise bouts and completed a valid skin type scale. Participants wore an Omron HR500U (OHR) and a Mio Alpha (MA), two commercial wearable photoplethysmographic heart rate monitors. Data were compared to a Polar RS800CX (PRS). Means and error were calculated between devices using minutes 2–5. Compared to PRS, MA data was significantly different in walking, biking (2.41?±?3.99?bpm and 3.26?±?11.38?bpm, p?<?0.05) and weight lifting (23.30?±?31.94?bpm, p?<?0.01). OHR differed from PRS in walking (4.95?±?7.53?bpm, p?<?0.05) and weight lifting (4.67?±?8.95?bpm, p?<?0.05). MA during elliptical, stair climbing and biking conditions demonstrated a strong correlation between jogging speed and error (r?=?0.55, p?<?0.0001), and showed differences in participants with less photosensitive skin.     

Enhanced cardiac and attentional responding to fearful faces in 7-month-old infants

Orienting of attention to emotionally negative stimuli is accompanied by rapid heart rate (HR) deceleration, reflecting enhanced attentional and sensory processing. We studied whether similar emotional modulation of cardiac responding is observed in infants. HR and eye movements were recorded from 7-month-old infants while they observed a fearful or happy face that was flanked after 700 ms by a peripheral distractor for 2000 ms. An attentional bias for fearful faces was indicated by less frequent and longer latency saccades toward the distractors during fearful than happy trials. HR deceleration was significantly larger during fearful than happy trials on which infants did not make a distractor-directed saccade. For trials with a distractor-directed saccade, no difference between fearful and happy faces emerged. Thus, the bias to attend preferentially to fearful faces is accompanied by a concomitant increase in the cardiac orienting response.     

Cortical thickness,resting state heart rate,and heart rate variability in female adolescents

Resting state heart rate variability (HRV) is a psychophysiological marker that has gained increasing research interest, in particular in developmental neuroscience. HRV has been shown to be associated with mental and physical health, beyond simple measures of heart rate (HR) and shows inter‐ and intraindividual variance across aging. Recently, three studies reported on a positive correlation between resting state HRV and cortical thickness in selected regions of interest (ROIs) in adult samples. Structural thickness, HRV, and HR change during the sensitive period of adolescence. Previously, no study has addressed the structural concomitants of resting HR and HRV in adolescents. Cortical thickness (3‐T MRI), HR, and HRV were recorded in 20 healthy, female adolescents (mean age: 15.92 years; SD = 1.06; range: 14–17). In line with existing research in adults, cortical thickness in a number of ROIs was associated with resting state HRV but not HR. The comparison of regression analyses using the Bayes factor revealed evidence for a correlation between HRV and cortical thickness of the bilateral rostral anterior cingulate cortex. However, unlike in adults, greater cortical thickness was associated with reduced HRV in female adolescents. Analyses on HR showed no superior model fit. Results suggest that greater HRV might be beneficial for cortical development during adolescence (cortical thinning). On the other hand, cortical development might determine changes in autonomic nervous system function in adolescents. Future studies are needed to replicate these findings in larger samples including boys and to test these hypotheses in longitudinal designs.     

The mindful attention and awareness scale is associated with lower levels of high-frequency heart rate variability in a laboratory context

Trait mindfulness has been associated with well-being. A key component of trait mindfulness is intentional attention and awareness which is most commonly measured by the Mindful Attention and Awareness Scale (MAAS). This study investigated the relationship between the MAAS and cardiovascular (HF-HRV, heart rate) reactivity to two laboratory stressors that evoked different patterns of change in heart rate (HR). One stressor (viewing a video of a surgery) evoked HR deceleration while the other stressor (mental arithmetic) evoked HR acceleration. Undergraduate students completed the MAAS and were then exposed to the two stressors while ECG (electrocardiography) was recorded. Findings support the reliability of the stressors to induce expected differential cardiovascular responses and explicate the role of parasympathetic activation. Further, a main effect for MAAS was observed indicating that across laboratory conditions, persons scoring higher on the MAAS had lower HF-HRV relative to persons scoring lower on the MAAS. These findings suggest that higher levels of intentional attention and awareness in a laboratory context might promote parasympathetic withdrawal because these participants were more vigilant, experienced higher cognitive load, and detected more threat cues. Implications for the MAAS and cardiovascular responses to stress are discussed.     

Reinstatement maintains a memory in human infants for 1(1/2) years

This study tested the proposition of Campbell and Jaynes (1966) that reinstatement is the mechanism by which early memories are maintained over a significant period of development. In four progressive replications, 6-month-old human infants learned to move a miniature train around a track by lever-pressing. They received a brief reinstatement at 7, 8, 9, 12, and 18 months of age and a final retention test at 2 years of age. Although 6-month-olds usually remember this task for only 2 weeks, after five reinstatements they exhibited significant retention 1(1/2) years later. Untrained yoked controls that received the same reinstatement regimen exhibited no retention after any delay. These findings reveal that the immaturity of the brain at the time of encoding is not the rate-limiting step in whether infants remember over the long term. Rather, as long as infants periodically encounter a nonverbal reminder, they can maintain early memories over a significant period of development.     

Effects of vital exhaustion on cardiac autononomic nervous functions assessed by heart rate variability at rest in middle-aged male workers

We investigated the effects of vital exhaustion (VE) on cardiac autonomic functions in relation to working conditions such as overtime and frequent business trips, and to lifestyles such as smoking on 52 healthy middle-aged male workers. VE was evaluated by an abbreviated Maastricht Vital Exhaustion Questionnaire. Cardiac autonomic function atsupine rest was assessed by spectral analysis of heart rate variability inanannual healthcheckup.Themeanamplitudeofthehigh frequency(HF: 0.15-0.4 Hz) component was lowerinthe high-VE group, whereas no significant difference in the ratio ofthe low frequency (LF: 0.04-0.15 Hz) component powerto HF power (the LF/HF ratio) was observed among VE groups. There were significant interactive effects of VE and smoking on HF amplitude, and of VE and frequent business trips on the LF/HF ratio. VE symptoms were related to the suppression of the cardiac parasympathetic nervous functionat rest in middle-aged male workers, but not to the alteration in sympathovagal balance. Smoking and overwork such as frequent business trips may amplify the autonomic dysfunction in relation to VE among workers with a pronounced feeling of VE.