Heart Rate Variability and Academic Performance of First-Year University Students.

Background: Heart rate variability (HRV) measures have been shown to be positively associated with cognitive processing, while a positive association between cognitive processing and academic performance has been demonstrated.

Objectives: To determine whether resting HRV or HRV marker response to either a cognitive or an orthostatic challenge is significantly associated with a first-year university student's academic performance.

Method: HRV markers used in the study included total power (TP) as a measure of overall HRV and the root mean square of successive differences (RMSSD) as a measure of parasympathetic influence on the heart.

Validity of Commonly Used Heart Rate Variability Markers of Autonomic Nervous System Function.

Background: Despite strong reservations regarding the validity of a number of heart rate variability (HRV) measures, these are still being used in recent studies.

Aims: We aimed to compare the reactivity of ostensible sympathetic HRV markers (low and very low frequency [LF and VLF]) to that of electrodermal activity (EDA), an exclusively sympathetic marker, in response to cognitive and orthostatic stress, investigate the possibility of LF as a vagal-mediated marker of baroreflex modulation, and compare the ability of HRV markers of parasympathetic function (root mean square of successive differences [RMSSD] and high frequency [HF]) to quantify vagal reactivity to cognitive and orthostatic stress.

Results: None of the purported sympathetic HRV markers displayed a reactivity that correlated with electrodermal reactivity.

EEG Brain Wave Activity at Rest and during Evoked Attention in Children with Attention-Deficit/Hyperactivity Disorder and Effects of Methylphenidate.

Objective: The aim of this study was to assess baseline EEG brain wave activity in children with attention-deficit/hyperactivity disorder (ADHD) and to examine the effects of evoked attention and methylphenidate on this activity.

Method: Children with ADHD (n = 19) were tested while they were stimulant free and during a period in which they were on stimulant (methylphenidate) medication. Control subjects (n = 18) were tested once.