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Heart Rate Variability Biofeedback for Postconcussion Syndrome: Implications for Treatment


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Heart Rate Variability (HRV) Biofeedback is used to restore balance in the activity of the sympathetic and parasympathetic branches of the autonomic nervous system by increasing or reducing the activity of either. Researchers have postulated that a fundamental cause of refractory postconcussion syndrome (PCS) is physiologic dysfunction that fails to return to normal after concussion. The primary physiologic issues identified have been altered autonomic function and impaired cerebral autoregulation. Evidence has shown that aerobic exercise training increases parasympathetic activity, reduces sympathetic activation, and improves cerebral blood flow so it may, therefore, help to reduce concussion-related physiological dysfunction. The authors hypothesize that HRV biofeedback training will ameliorate PCS by improving autonomic balance as well as cerebral autoregulation, and that there will be a relationship between increased interval variability and postconcussion symptom reduction.
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Biofeedback ÓAssociation for Applied Psychophysiology & Biofeedback
Volume 41, Issue 3, pp. 136–143
DOI: 10.5298/1081-5937-41.3.02
A Preliminary Study: Heart Rate Variability Biofeedback
for Treatment of Postconcussion Syndrome
Leah Lagos, PsyD, BCB,
James Thompson, PhD, BCN,
and Evgeny Vaschillo, PhD
Leah Lagos LLC, New York, NY;
Evoke Neuroscience, New York, NY;
Rutgers University, Piscataway, NJ
Keywords: biofeedback, heart rate variability, concussion, mild traumatic brain injury, baroreflex gain
Heart rate variability (HRV) biofeedback (BFB) can be used
to reduce activation of the sympathetic nervous system
(SNS) and increase activation of the parasympathetic
nervous system (PNS). A growing body of research
suggests that increased arousal of the SNS contributes to
the sustained state of postconcussion syndrome (PCS). It
has also been postulated that underactivation of the PNS
may also play a role in the postinjury state of autonomic
dystonia, wherein the autonomic nervous system is in a
state of imbalance and does not return to normal. In
addition to autonomic imbalance, patients who are
generally advised not to engage in physical exertion until
asymptomatic from concussion, are known to experience
secondary symptoms of fatigue and reactive depression.
Recent research has established that such symptoms can
delay the recovery from concussion indefinitely. By
addressing both autonomic dysfunction and the secondary
symptoms of depression and anxiety, HRV BFB may be an
effective treatment for PCS by strengthening self-regula-
tory control mechanisms in the body and improving
autonomic balance. Recent studies have suggested that
HRV BFB has a positive impact in reducing stress and
anxiety among athletes, and concussed athletes with higher
perceived control over their symptoms have been shown to
have faster recoveries post-injury. The primary purpose of
the following case study was, therefore, to assess the
feasibility of implementing HRV BFB with a concussed
athlete suffering from postconcussion syndrome (PCS). The
second objective was to prospectively examine the impact
of ten weeks of HRV biofeedback on refractory postcon-
cussion symptoms. During this pilot case study, the athlete
attended 10 weekly sessions of HRV BFB, according to the
protocol set forth by Lehrer, Vaschillo, and Vaschillo
(2000). After 10 weeks of HRV biofeedback, the athlete
exhibited clinically significant improvements in total mood
disturbance, postconcussion symptoms, and headache
severity. The results suggest that HRV BFB may be a
useful adjunctive treatment for PCS, associated with
increases in HRV and enhanced cardiovagal activity. Given
these findings, a randomized controlled trial is warranted.
The neurosurgeon Benjamin Bell wrote in 1787 that ‘‘every
affection of the head attended with stupefaction, when it
appears as the immediate consequence of external violence,
and when no mark or injury is discovered, is in general
supposed to proceed from commotion or concussion of the
brain, by which is meant such a derangement of this organ
as obstructs its natural and usual functions, without
producing such obvious effects on it as to render it capable
of having its real nature ascertained by dissection’’ (Shaw,
2002). This definition continues to be supported by today’s
research in two ways. First, it does not imply a short-term
deficit that resolves quickly. This is evidenced by the up to
10% of sports-related and 33% of non-sports-related
concussive injuries that develop into postconcussion
syndrome (PCS). PCS is defined by the World Health
Organization’s International Classification of Diseases, or
ICD-10, as three or more of the following symptoms:
headache, dizziness, fatigue, irritability, insomnia, concen-
tration difficulty, or memory difficulty to resolve within a
3–6 week period (Boake et al., 2005). Second, the definition
provided by Bell notes that the underlying pathology of the
symptoms cannot be ascertained by dissection, thus
accurately noting that concussion is a physiological injury,
not an anatomical injury, as evidenced by negative
structural imaging results (CT, MRI) in concussive injuries
(Barth, Freeman, Boshek, & Varney, 2001; Guskiewicz,
Ross, & Marshall, 2001).
For over a century, research has demonstrated that brain
injury causes cardiac dysfunction, cerebral hypo-perfusion,
and heart rate variability (HRV) abnormality (Cushing,
1901; Furgała et al., 2007; Kahraman et al., 2010).
Additionally, concussion severity relates directly to HRV
statistics supporting the complex bidirectional nature of
heart–brain interactions (Gall, Parkhouse, & Goodman,
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2004; Goldstein, Toweill, Susanna, Sonnenthal, & Kim-
berly, 1998; Grippo & Johnson, 2009; Jennings & Zanstra,
2009; King, Lichtman, Seliger, Ehert, & Steinberg, 1997).
The correlation between HRV frequency power normali-
zation and brain injury recovery suggests that autonomic
nervous system balance is a factor in both the brain insult
and a mechanism for concussion resolution (Keren et al.,
Based on the large percentage of concussive injuries that
produce PCS, the detrimental effects of PCS on physical,
social and psychological health, and the known ineffective-
ness of symptom-based treatments to resolve PCS, there is
a need to find effective interventions that treat the
underlying injury (Leddy, Sandhu, Baker, Sodhi, & Willer,
2012). Given the understanding that concussion is a
physiological injury, it is not surprising that recent research
and clinical work that apply physiological treatment
modalities, such as subsymptom exercise training are being
shown to be successful in resolving not only the symptoms
involved with PCS but also many of the underlying
physiological disequilibria present in concussive injuries
(Leddy, Kozlowski, Fung, Pendergast, & Willer, 2007).
The primary goals for this study, therefore, were to
establish the safety and potential effectiveness of HRV
biofeedback (BFB) for treatment of PCS. Specifically, this
study addressed two main research areas. First, it examined
the impact of HRV BFB on mood, headaches, and severity
of postconcussion symptoms. Second, the impact of HRV
BFB on physiological performance as defined by low
frequency (LF) HRV, total HRV, and respiration rate was
measured. Consistent with previous literature, it was
hypothesized that HRV biofeedback would reduce PCS by
restoring autonomic balance and cerebral autoregulation
and that there would be a relationship between baroreflex
gain and symptom reduction.
Background of Patient
The patient in this applied case study was a 42-year-old
competitive athlete who suffered her first concussion
during practice. The diagnosis of postconcussion syndrome
was determined by her primary care physician after clinical
examination and was confirmed by an ImPACT test
(immediate postconcussion assessment and cognitive test-
ing), which assessed the severity of her postconcussion
symptoms. Upon obtaining an initial score of 63 indicating
high severity of postconcussion symptoms, the patient was
prescribed bed rest and 10 mg of Zoloft. At a follow-up
visit, three and a half months following the initial injury,
the patient reported an increase of postconcussion symp-
toms and scored an ImPACT score of 65. Given the lack of
evidence-based interventions to address PCS, the physician
referred the patient for heart rate variability (HRV)
biofeedback training to address physiological dysfunction.
At the onset of HRV biofeedback, the patient reported
experiencing 14 out of 16 postconcussion symptoms set
forth by the World Health Organization (Boake et al.,
2005). The patient continued her regimen of bed rest and 10
mg of Zoloft while participating in the biofeedback training.
The 10-week HRV BFB protocol designed by Lehrer,
Vaschillo, and Vaschillo (2000) was implemented with the
patient. Each session lasted 45 to 60 minutes and included
four activities (A: baseline, B and C: biofeedback training,
and D: baseline) for five minutes each. Sessions 1, 4, 7, and
10 served as recording sessions. ECG and respiration were
recorded during all four tasks. In addition, measures of
headache severity, daily life functioning, and mood were
obtained during each recording session. At the initial
session, the patient’s resonance frequency was identified as
0.1 Hz, or six breaths per minute. The resonance frequency
is the rate of breathing (and frequency of heart rate
oscillation), at which the individual produces the greatest
heart rate variability. Sessions 2, 3, 5, 6, 8, and 9 were
conducted as training sessions without physiological
measures. During training sessions, the patient was taught
to breathe slowly but not too deeply at her resonance
frequency using abdominal and pursed lip breathing
techniques. For homework, the patient was asked to engage
in two 20-minute breathing practices each day for ten
consecutive weeks. The patient submitted a weekly log of
her breathing practice times to the experimenter. All data
collection was conducted at approximately the same time of
day at the experimenter’s therapy office in Manhattan.
Psychometric Measures
The patient completed questionnaires that assessed the
severity of postconcussion symptoms, impact of headaches
on daily functioning, and mood following the injury.
Rivermead Postconcussion Questionnaire (RPQ). The RPQ
is a 16-item measure of PCS severity. The test asks the
patient to rate the severity of 16 of the most common
published PCS symptoms. In each case, the symptom is
compared with how severe it was before the injury
occurred. Questions examine the cognitive, somatic, and
emotional symptoms concussed patients may experience
following their injury. Responses range from 0 (not
experienced at all) to 4 (a severe problem), and the
maximum score that can be achieved is 64.
Lagos et al.
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Headache Impact Test (HIT-6). The HIT-6 is a scientifically
validated short form questionnaire to assess headache
impact (range: 36–78). Six questions cover pain severity,
loss of work and recreational activities, tiredness, mood
alterations, and cognition. A HIT-6 score of less than 48 is
interpreted as consistent with little impact; 50–54 shows
some impact, 56–58 shows substantial impact, and .60
shows severe impact.
The Profile of Mood States–Short Form (POMS-SF). The
37-item POMS-SF consists of six affective subscales
including tension, depression, anger, vigor, fatigue, and
confusion. Responses range from 0 (not at all) to 4
(extremely). Scores are interpreted as ranging from a low
score indicative of well-being to a higher score associated
with distress. Total mood disturbance was calculated by
subtracting positive mood scores (vigor and self-esteem)
from the sum of negative mood scores (Grove &
Prapavessis, 1992).
Physiological Measures
A ProComp Infinitie(Thought Technology, Montreal,
Canada) system was used to collect cardiovascular data as
well as to provide biofeedback training. A blood volume
pulse sensor measured cardiovascular activity, including
HR and HRV. To record respiration, a respiration strain
gauge was placed around the abdomen. As the gauge
stretched, the voltage across the tube increased, and relative
changes in length were measured with a range of 1–100
units of relative strength.
Data Analysis
Beat-to-beat RR intervals (RRI) and HR were assessed from
the BVP signal. Thought Technology software (Montreal,
Canada) calculated both the frequency domain measures
from both signals. For each dependent variable, data were
graphed and visually analyzed to evaluate the effects of the
intervention (Barlow & Hersen, 1984). These graphs were
interpreted with respect to immediacy and level of change
pre- and postintervention, amount of overlapping data
points across phases, and changes in slope and/or variability
across sessions (Hrycaiko & Martin, 1996; Thelwell,
Greenlees, & Weston, 2006).
As indicated in Figure 1, the athlete showed a clinically
significant decrease in total mood disturbance from 72 to 24
between sessions 1 and 10, respectively. Notably, the
athlete showed improvements in five out of five negative
mood states between session one and session ten on the
POMS-SF (Figure 2). The most dramatic change in mood
symptoms related to depression. In session 1, the patient
scored 25, which is in the severe range for depression.
Following 10 weeks of HRV biofeedback, the patient
reported a score of 2, which is associated with mild
depression. In addition, there was also an increase in vigor,
from a score of 5 (low severity) to 13 (moderate severity).
Figure 1. Profile of Mood States (POMS), short form.
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The impact of headaches on daily functioning decreased
from a score of 67 to 48 after HRV biofeedback (Figure 3).
A score of 67 in the initial session indicated that the athlete
had been experiencing headaches that severely impacted her
daily life and disabled her from enjoying family, work, and
social activities. After the tenth week of HRV BFB training,
the athlete scored a 48, which indicated that her headaches
had little to no impact on her ability to function in daily life.
A score of 67 in the initial session indicated that the athlete
had more severe headaches after three months following
injury than the average concussed athletes experiences
three days after the concussion (M¼45.4, SD ¼7.0;
McLeod, Bay, Valier, Lam, & Parsons, 2013).
Figure 2. Profile of Mood States (POMS), short form.
Figure 3. Headache (HIT-6) questionnaire.
Lagos et al.
Biofeedback |Fall 2013
Postconcussion Symptoms
The prevalence of postconcussion symptoms, as measured
by the RPCQ, was reduced from 57 to 15 after HRV
biofeedback (Figure 4). The initial score of 57, prior to
biofeedback training, reflected that the athlete experienced
severe postconcussion symptoms. A score of 15 in the tenth
session demonstrated that the athlete possessed minimal to
mild postconcussion symptoms. In addition, a score of 57 at
the initial session denoted that the athlete had more severe
postconcussion symptoms than the average athlete with
PCS (M¼19.1, SD ¼11.9; Ingerbrigsten, Waterloo,
Marup-Jensen, Attner, & Romner, 1998).
Physiological Performance
The data demonstrate that following 10 weeks of biofeed-
back treatment there is an increase in the patient’s total
HRV assessed using HR STD DEV in task A (Figure 5), and
patient’s baroreflex sensitivity assessed using LF HRV in
tasks A and C (Figure 6, Figure 7). The amplitude of
oscillation in response to ~0.1 Hz breathing strongly
correlates with baroreflex sensitivity.
Training in HRV biofeedback was followed by: (a) large
short term and longer term effects on indices of autonomic
control, (b) decreases in mood disturbances and other
negative emotional states, and (c) improvements in
headaches. The authors of this study believe that the
HRV biofeedback provided three therapeutic aspects. First,
HRV biofeedback elicited high amplitude oscillations in
cardiovascular functions and thereby activated and im-
proved the performance of autonomic reflexes. This finding
is consistent with previous studies in which HRV
biofeedback training has been shown to increase baroreflex
sensitivity (Lehrer et al., 2003). Second, the resonance
frequency breathing increased LF HRV significantly,
suggesting that sympathetic–vagal balance in the autonom-
ic nervous system was restored. Lastly, high amplitude
oscillation in heart rate, caused by resonance in the
baroreflex closed loops, modulates the brain through
afferent firing from baroreceptors, and restores the balance
between inhibition and excitation processes in the brain.
Limitations and Future Directions
As this was a preliminary and clinical case study, our results
do not lead to a definitive conclusion. The absence of a
control group allows the possibility that the patient’s
improvement was due to placebo effect or nonspecific
factors rather than the intervention, or that the results will
not be replicated in all cases. We believe that spontaneous
recovery, however, is unlikely during the 10 weeks of HRV
biofeedback, since the patient was symptomatic for many
months prior to the HRV biofeedback program and did not
improve after 1 to 3 months of standard treatment.
Furthermore, the patient’s physiological and emotional
Figure 4. Rivermead Postconcussion Symptom Questionnaire (RPCSQ).
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Figure 6. Low frequency heart rate variability (LFHRV).
Figure 5. Heart rate standard deviation (HR STD DEV).
Lagos et al.
Biofeedback |Fall 2013
symptoms improved concomitantly after the HRV biofeed-
An additional limitation of this study is that the
mechanisms by which neurocognitive symptoms of PCS
were impacted by HRV biofeedback were not adequately
investigated in this study. Assessing the impact of HRV
biofeedback on attention and cognitive processing speed
could reveal much about the role of the vagus nerve and
baroreflex gain in mediating cerebrovascular changes.
Thayer and Brosschot (2005) have noted that the autonomic
nervous system includes the afferent interoceptive arm and
the efferent visceral motor arms of the sympathetic and
parasympathetic nervous system as well as higher level
integrative and regulatory neural networks found at
various levels in the brain. It is possible that the
disequilibrium in these integrative and regulatory neural
networks maybe related to the source of autonomic
dystonia that characterizes PCS. There is a growing
consensus that one fundamental cause of refractory PCS
is physiological dysfunction that fails to return to normal
after concussion (Leddy, Kozlowski, Fung, Pendergast, &
Willer, 2007). The frequent comorbidity of PCS and major
depression disorder (Belanger & Vanderplog, 2005) and
evidence of shared exacerbated activity of excitation and
depressed inhibition processes in the brain (Leddy et al.,
2007) further highlights a potential dysfunction of these
neural circuits. Indeed, one of the patient’s most dramatic
changes in PCS symptoms was the significant improvement
in depression symptoms. This supports the hypothesis that
the effects of HRV biofeedback on these higher-level brain
functions may be involved in symptom relief in PCS.
Future studies may benefit from including quantitative
electroencephalogram measures to explore the role of the
vagus nerve and baroreflex sensitivity in mediating
cerebrovascular changes.
In summary, despite the limitations inherent in this
small case study, HRV biofeedback shows promise for the
adjunctive treatment of PCS. Our findings demonstrate that
compared to symptom management intervention programs
that modulate symptom severity, for example antidepres-
sant medications and sleep aids, HRV biofeedback is a safe
and effective intervention that directly addresses at least
some of the fundamental physiological dysfunction that
occurs in the concussed patient. Additional assessment of
this intervention is warranted in larger, controlled trials.
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Figure 7. Baroreflex sensitivity.
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Leah Lagos James Thompson Evgeny Vaschillo
Correspondence: Leah Lagos, 635 Madison Avenue, Fourth Floor,
New York, NY 10022, email:
Lagos et al.
Biofeedback |Fall 2013
... [5][6][7][8] For example, sleep disturbance could: contribute to or exacerbate comorbid conditions such as depression, fatigue and pain 1,9 ; worsen recovery because the normal restorative and recuperative functions of sleep are disrupted 3 ; interfere directly with rehabilitation 5 ; or signal ongoing disruption of neurophysiological processes. 6,10,11 It is possible that sleep disturbance before the TBI is also a contributor to poor outcome by increasing vulnerability or reducing recovery capacity. ...
... There is limited literature assessing treatment approaches in this population. 10 This study's findings suggest that some sleep therapies (e.g., bright light therapy, melatonin, both of which are targeted at circadian dysfunction) may be of limited use after mTBI. Psychological and behavioral therapies such as cognitive behavioral therapy for insomnia (CBTi), however, which is the first-line therapy recommended for insomnia, may be beneficial. ...
Full-text available
Sleep disturbance following mTBI is commonly reported as debilitating and persistent. However, the nature of this disturbance is poorly understood. This study sought to characterize sleep following mTBI compared to a control group. A cross-sectional matched case control design was used. Thirty-three individuals with recent mTBI (1-6 months ago) and 33 age, gender, and ethnicity matched controls completed established questionnaires of sleep quality, quantity, timing, and sleep-related daytime impairment. MTBI participants were compared to an independent sample of close-matched controls (CMCs; n = 33) to allow partial internal replication. Compared to controls, people with mTBI reported significantly greater sleep disturbance, more severe insomnia symptoms, a longer duration of wake after sleep onset (WASO), and greater sleep-related impairment (all medium to large effects, Cohen's d >0.5). No differences were found in sleep quantity, timing, sleep onset latency, sleep efficiency or daytime sleepiness. All findings except a measure of sleep timing (i.e., sleep midpoint) were replicated for CMCs. These results indicate a difference in the magnitude and nature of perceived sleep disturbance following mTBI compared with controls, where people with mTBI report poorer sleep quality and greater impairment from their sleep. The finding that other sleep parameters did not differ has implications for treatment. These findings should guide the provision of clearer advice to patients about the aspects of their sleep that may change following mTBI and which treatments may be suitable.
... There is increasing interest about the effects of acute concussive injury on the capacity of the central nervous system to appropriately regulate peripheral functions such as cardiovascular rhythm, metabolism and temperature regulation and how this may relate to prolonged recovery from concussion [1][2][3][4]. Studies that have specifically addressed disruption in regulatory function after mild or severe traumatic brain injury have generally focused on abnormalities in autonomic control over the sympathetic and parasympathetic nervous system, including control of heart rate (HR) and heart rate variability (HRV) [3,[5][6][7]. ...
... A more sophisticated understanding of cardiovascularautonomic dysregulation after concussive injury is imperative for the evaluation and treatment of concussion. Current therapies for concussed patients, including some which utilize biofeedback for retraining of the autonomic system after injury [1], while wellintentioned, may be limited by an oversimplification of the nature of this dysregulation. In contrast to the consideration of increased cardiac sympathetic activity after injury as the predominant cause of autonomic problems after concussion, our results suggest that earlier intervention to target the parasympathetic system may help prevent prolonged regulatory problems. ...
Full-text available
Objective Research suggests that one physiological effect of concussion is a disruption in regulation of autonomic nervous system control that affects the balance between parasympathetic and sympathetic output. While changes in heart rate after concussion have been observed, the nature of the heart rate change during progressive exercise has not been well evaluated in acutely symptomatic patients. Additionally, little is known about the relationship between HR and RPE in this population. Methods We compared changes in heart rate and perceived effort during graded treadmill exertion in recently concussed patients to elucidate the effect of brain injury on cardiovascular response to exercise. Resting HR, HR on exercise initiation, and changes in HR and RPE during the Buffalo Concussion Treadmill Test (BCTT) were compared on two test visits: When patients were symptomatic (acute) and after recovery. Results were compared with the test-retest results obtained from a control group consisting of healthy, non-concussed individuals. Results Patients had a significantly lower HR at onset of exercise when acutely concussed as compared to when recovered and reported greater perceived exertion at every exercise intensity level when symptomatic, despite exercising at lower workloads, than when recovered. Sympathetic response to increased exertion was not affected by concussion - HR increased in response to exercise at a comparable rate in both tests. These differences observed in response to exercise between the first BCTT and follow-up evaluation in initially concussed patients were not present in non-concussed individuals. Conclusion Our results suggest that during the acute phase after concussion, acutely concussed patients demonstrated an impaired ability to shift from parasympathetic to sympathetic control over heart rate at the onset of exercise. Changes in the autonomic nervous system after concussion may be more complex than previously reported. Continued evaluation of autonomic regulatory effects in the acute phase after concussion is warranted.
... Lehrer et al. [84] developed a protocol for heart rate variability training in medical conditions, particularly asthma. Lagos et al. [85,86] modified Lehrer et al.'s heart rate variability training successfully with concussed adolescents. They used a biofeedback protocol taught in the office but then practiced at home. ...
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Background: The neuropsychological, physical, vestibular and oculomotor sequelae of sports-related concussion are extremely well documented. However, there is a paucity of interventions for these symptoms in refractory sports-related concussions. Aim: The intent of this article is to review the known and emerging neuropsychological and psychological rehabilitation interventions for reducing morbidity in refractory sports-related concussions (SRCs). Methods: The authors openly acknowledge the limited amount of empirical data available for review, as did the Zurich consensus papers, but posit a mindful and ethical approach towards rehabilitation interventions in the absence of evidence-based guidelines. Further, rehabilitation interventions proven useful with similar injuries or illnesses, particularly non-sports-related mild TBI, will be reviewed for applicability. Such interventions include Cognitive-Behavioural psychotherapy, biofeedback, cranial electrical stimulation, neurofeedback and cognitive rehabilitation. Results and conclusions: Modified approaches for rehabilitation with young children within family and school systems are provided. Recommendations for further research are offered.
... While this patient was much more severely injured than a person with a concussion, after a lengthy course of treatment he showed improvement on multiple QEEG parameters, as well as three HRV parameters, and was able to function successfully in his personal and work life. Lagos et al. (2012) provide a comprehensive rationale for HRV BFB in prolonged PCS from hyperactivation of the sympathetic nervous system and hypoactivation of the parasympathetic nervous system. In addition to changes in HRV as an outcome measure for BFB intervention, they also recommend multimodal measures, such as cardiovascular and neurovegetative functioning, and quality of life indicators. ...
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The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.
Traumatic brain injury (TBI) at all levels, from concussion through severe TBI, can negatively impact multiple systems in the human body. This multisystem disturbance is evidenced by the distributed nature and complex symptom patterns of TBI individuals including brain-based symptoms such as cognitive deficits and emotional lability, as well as autonomic symptoms such as headache, nausea, and dizziness. In order to properly diagnose, predict prognosis, and guide recovery, assessment following TBI must include all physiologic systems that may have disrupted function following TBI, and must include the use of appropriate tools in order to administer a comprehensive assessment. Electrophysiology is the only available tool that directly reflects real-time neurological function through the measurement of the moment-to-moment electrical discharges of firing neurons. Tools such as event-related potentials (ERPs), derived from the electroencephalogram, and heart rate variability, derived from the electrocardiogram, are reliable, valid, and clinically available tools that have decades of research and clinical support for their use in evaluating the underlying pathophysiology of TBI on nervous system function. This chapter reviews ERP and autonomic nervous system biomarkers that have demonstrated utility in assessment and recovery tracking for individuals suffering TBI.
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Background: Persistent Sport-Related Post-Concussion Syndrome is often diagnosed with any type of prolonged PCS symptoms. However, there are not specific diagnostic criteria for PPCS such that misdiagnosis often occurs. Further, the signs and symptoms of PCS overlap with other common illnesses such as depression, anxiety, migraines, ADHD and others. Misdiagnosis may lead to less than efficacious treatment, resulting in prolonged symptoms. Objective: This article will review relevant evidence-based literature on PCS, pointing out the lack of a systemic diagnostic framework. It will also provide evidence that highlights the multiple conflicting findings in the literature. This article will posit the BioPsychoSocial framework as the best diagnostic framework for understanding the impact of concussions on the person and to generate individualized and personal interventions. Methods: A narrative review of sport concussion-related articles was conducted, after extensive searches of relevant and non-relevant literature by each author, as well as articles recommended by colleagues. Articles varied from American Academy of Neurology Class I to IV for evaluation and critique. Class IV articles were reviewed, as there is much public misconception regarding sport and other concussion treatment that needed identification and discussion. Results: Articles reviewed varied by quality of research design and methodology. Multiple symptoms, recovery patterns and rehabilitation treatment approaches are purported in the sport-related concussion literature. Current consensus data as well as the mixed and contradictory findings were explored. Conclusions: Persistent Sport-Related Post-Concussion Syndrome is a topic of great interest to both professionals and the general public. There is much misunderstanding about the etiology, causation, diagnostic formulations, symptom presentation, prolonging factors and treatment involved in this syndrome. This article posits an individualized multi-system diagnostic formulation, examining all relevant factors, as generating the best interventions for neurorehabilitation of Persistent Sport-Related Post-Concussion Syndrome.
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Background: Fearful and anxious behaviour is especially common in children, when they come across new situations and experiences. The difference between normal worry and an anxiety disorder is in the severity and in the interference with everyday life and normal developmental steps. Many longitudinal studies in children suggest that anxiety disorders are relatively stable over time and predict anxiety and depressive disorders in adolescence and adulthood. For this reason, the early diagnostic and treatment are needed. Researchers supposed that anxiety is a result of repeated stress. Additionally, some genetic, neurobiological, developmental factors are also involved in the aetiology. Methods and subjects: The aim of this article is to summarize and to present our own results obtained with the assessment and treatment of different forms of anxiety disorders in children and adolescents such as: Posttraumatic Stress Disorder (PTSD), Obsessive Compulsive Disorder (OCD), Dental anxiety, General Anxiety Disorder (GAD), and Anxious-phobic syndrome. Some results are published separately in different journals. a) Post Traumatic Stress Disorder (PTSD) in 10 young children aged 9 ± 2, 05 y. is evaluated and discussed concerning the attachment quality. b) The group with OCD comprises 20 patients, mean age 14,5 ± 2,2 years, evaluated with Eysenck Personality Questionnaire (EPQ), Child behaviour Checklist (CBCL), K-SADS (Schedule for Affective Disorders and Schizophrenia for School age children), Beck Depression Inventory (BDI), SCWT (Stroop Colour Word task), WCST (Wisconsin Card Scoring test). c) Dental stress is evaluated in a group of 50 patients; mean age for girls 11,4 ± 2,4 years; for boys 10,7 ± 2,6 years, evaluated with (General Anxiety Scale (GASC), and Eysenck Personality Questionnaire (EPQ). d) Minnesota Multiphasic Personality Inventory (MMPI) profiles obtained for General Anxiety Disorder in 20 young females and 15 males aged 25,7± 5,35 years, and a group with Panic attack syndrome N=15 aged 19,3±4,9 years are presented and discussed by comparison of the results for healthy people. e) Heart Rate Variability (HRV) was applied for assessment and treatment in 15 anxious-phobic patients, mean age 12, 5±2,25 years and results are compared with other groups of mental disorder. Results: Children with PTSD showed a high level of anxiety and stress, somatization and behavioural problems (aggression, impulsivity, non-obedience and nightmares), complemented by hypersensitive and depressed mothers and misattachment in the early period of infancy. Consequently, the explanation of the early predisposition to PTSD was related to be the non-developed Right Orbital Cortex. The later resulted from insecure attachment confirmed in all examined children. The obtained neuropsychological profile of children with OCD confirmed a clear presence of obsessions and compulsions, average intellectual capacities, but the absence of depressive symptoms. Executive functions were investigated through Event Related Potentials on Go/NoGo tasks. Results showed that no significant clinical manifestations of cognitive dysfunction among children with OCD in the early stage of the disorder are present, but it could be expected to be appearing in the later stage of the disorder if it is no treated. In a study of 50 children randomly selected, two psychometric instruments were applied for measuring general anxiety and personal characteristics. It was confirmed that there was presence of significant anxiety level (evaluated with GASC) among children undergoing dental intervention. The difference in anxiety scores between girls and boys was also confirmed (girls having higher scores for anxiety). Results obtained with EPQ showed low psychopathological traits, moderate extraversion and neuroticism, but accentuated insincerity (L scale). L scales are lower by increasing of age, but P scores rise with age, which can be related to puberty. No correlation was found between personality traits and anxiety except for neuroticism, which is positively correlated with the level of anxiety. The obtained profiles for MMPI-201 in a group of patients with general anxiety are presented as a figure. Females showed only Hy peak, but in the normal range. However, statistics confirmed significant difference between scores in anxiety group and control (t= 2, 25164; p= 0, 038749). Males showed Hs-Hy-Pt peaks with higher (pathological) scores, related to hypersensitivity of the autonomic nervous system, as well as with manifested anxiety. Calculation confirmed significant difference between control and anxiety in men (t= 15.13, p=0.000). Additionally, MMPI profiles for patients with attack panic syndrome are also presented as a figure. Control scales for females showed typical V form (scales 1 and 3) related to conversing tendencies. In addition, females showed peaks on Pt-Sc scales, but in normal ranges. Pathological profile is obtained in males, with Hy-Sc peaks; this profile corresponds to persons with regressive characteristics, emotionally instable and with accentuated social withdraw. Heart rate variability (HRV) is a measure of the beat to beat variability in heart rate, related to the work of autonomic nervous system. It may serve as a psychophysiological indicator for arousal, emotional state and stress level. We used HRV in both, the assessment and biofeedback training, in a group of anxious-phobic and obsessive-compulsive school children. Results obtained with Eysenck Personality Questionnaire showed significantly higher psychopathological traits, higher neuroticism and lower lie scores. After 15 session HRV training very satisfying results for diminishing stress and anxiety were obtained.
In the course of rehabilitation we provided polygraphic examination of a group of 14 men who endured myocardial infarction or stroke one to three months ago. Fourteen men of a comparable age (55 years, on average), healthy from the aspect of diseases of the cardiovascular system, served as the control group. Examination was performed using a flexible data acquisition and feedback platform «Nexus-10 Mark II» (the Netherlands) allowing us to simultaneously record ECG, EMG, EEG, respiratory movements, pulse blood filling, skin temperature, electrodermal resistance, and a few other indices. It was found that patients suffering from complications of pathologies of the cardiovascular system were characterized by a significant increase in the electrodermal conductivity, clearly expressed tachypnea, and some trends toward tachycardia and decrease in the skin temperature. According to indices of the heart rate variability (HRV), the mean value of the Bayevskii stress index in patients was about three times higher than the analogous value in the control group, while the total power of the HRV spectrum was dramatically lower. The amplitude of tonic EMG activity recorded from mm. trapezii in the resting state considerably exceeded the respective value in control subjects. The amplitude of 8-13 Hz EEG oscillations in the Cz lead in patients was somewhat lower than in the control group, and increase in this index in the test with closing the of eyes in these subjects was manifested much slightly than in the control. Parallel recording of physiological (first of all, neurophysiological) indices allows researchers to effectively identify objective markers of the stress state developed after complications of diseases of the cardiovascular system; the respective data can be used in the curative procedures with the control of functions of the organism using a feedback technology by the parameters of activity of the functional systems (biofeedback control).
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Objective To determine the impact of concussion on general, fatigue-specific, and headache-specific Health-related quality of life (HRQOL). Design Repeated measures. Setting High school athletic facilities. Patients Two hundred and fifty-nine adolescent athletes who sustained a concussion diagnosed by their athletic trainer (218 males, 41 females, age=15.9±1.2 years, grade=10.0±1.1). Interventions Participants completed the paediatric Quality of Life Inventory (PedsQL), PedsQL Multidimensional Fatigue Scale (MFS), and Headache Impact Test (HIT-6) during a preseason baseline (BL) and on days 3 (D3), 10 (D10) and 30 (D30) post-concussion. Main Outcome Measures Dependent variables included: 4 PedsQL subscale scores (physical (PF), emotional (EF), social (SOF), school (SCF) functioning), 3 MFS subscale scores (general (GF), sleep (SLF), cognitive (CF) fatigue), and the HIT-6 total score. Higher scores on the HIT-6 and lower scores on the PedsQL and MFS indicate lower HRQOL. Analyses were conducted using generalised estimating equations with follow-up Bonferroni corrections. Results All omnibus tests were significant (p<0.001). Athletes reported significantly lower HRQOL on D3 than BL for PF (D3=77.8, 95% CI 75.1 to 80.4; BL=92.9, 95% CI 91.4 to 94.4), SCF (D3=78.6, 95% CI 76.3 to 80.8; BL=83.9, 95% CI 81.8 to 86.0), CF(D3=73.2, 95% CI 70.3 to 76.1; BL=82.6, 95% CI 79.9 to 85.1), GF (D3=74.9, 95% CI 72.0 to 77.9; BL=85.1, 95% CI 82.8 to 87.4) and HIT-6 (D3=51.5, 95% CI 50.3 to 52.6; BL=45.4, 95% CI 44.5 to 46.4). All D10 and D30 subscale scores were significantly higher than BL. Conclusions Concussed athletes demonstrated lower general, fatigue-specific, and headache-specific HRQOL in the immediate days post-injury. These findings corroborate reports of the symptoms experienced acutely post-concussion and align with a time when athletes are often restricted from participating in physical and cognitive activities. The effects of concussion on HRQOL appear short-lived, with recovery by 10 days post-injury. Acknowledgements This study was funded by a grant from the National Operating Committee for Standards on Athletic Equipment (NOCSAE). Competing interests None.
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The present study examined the effects of a soccer, midfielder-specific psychological skills intervention comprising relaxation, imagery and self-talk on position-specific performance measures. Using a multiple-baseline-across-individuals design, five participants had three per-formance subcomponents assessed across nine competitive matches. The results of the study indicated the position-specific intervention to enable at least small improvements on the three dependent variables for each participant. Social validation data indicated all participants to perceive the intervention as being successful and appropriate to their needs. The findings provide further evidence to suggest the efficacy of sport, and position-specific interventions. Suggestions for future research are provided.
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Examined the psychometric properties of a modified form of S. Schacham's short version of the Profile of Mood States (POMS) for a sample of competitive athletes. The revised scale consisted of 40 adjectives that measured tension, depression, fatigue, vigor, confusion, anger, and esteem-related affect. The scale was administered to 45 female netball players immediately after competition, with the Ss instructed to respond according to how they were feeling at that point in time. Reliability coefficients (Cronbach's alphas) for the subscales ranged from .66 to .95 with a mean of .80. Validity was examined by comparing the mood states of winners and losers. All subscales, except fatigue, produced significant differences between these groups. It was concluded that this modified form of the POMS has acceptable psychometric properties for use in a sport setting. (French, Spanish, German & Italian abstracts) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Prolonged symptoms after concussion are called post-concussion syndrome (PCS), which is a controversial disorder with a wide differential diagnosis. MEDLINE and PubMed searches were conducted for the years 1966 to 2011 using the search terms brain concussion/complications OR brain concussion/diagnosis OR brain concussion/therapy AND sports OR athletic injuries. Secondary search terms included post-concussion syndrome, trauma, symptoms, metabolic, sports medicine, cognitive behavioral therapy, treatment and rehabilitation. Additional articles were identified from the bibliographies of recent reviews. Of 564 studies that fulfilled preliminary search criteria, 119 focused on the diagnosis, pathophysiology, and treatment/rehabilitation of concussion and PCS and formed the basis of this review. Rest is the primary treatment for the acute symptoms of concussion. Ongoing symptoms are either a prolonged version of the concussion pathophysiology or a manifestation of other processes, such as cervical injury, migraine headaches, depression, chronic pain, vestibular dysfunction, visual dysfunction, or some combination of conditions. The pathophysiology of ongoing symptoms from the original concussion injury may reflect multiple causes: anatomic, neurometabolic, and physiologic. Treatment approaches depend on the clinician's ability to differentiate among the various conditions associated with PCS. Early education, cognitive behavioral therapy, and aerobic exercise therapy have shown efficacy in certain patients but have limitations of study design. An algorithm is presented to aid clinicians in the evaluation and treatment of concussion and PCS and in the return-to-activity decision.
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To evaluate the safety and effectiveness of subsymptom threshold exercise training for the treatment of post-concussion syndrome (PCS). Prospective case series. University Sports Medicine Concussion Clinic. Twelve refractory patients with PCS (6 athletes and 6 nonathletes). Treadmill test to symptom exacerbation threshold (ST) before and after 2 to 3 weeks of baseline. Subjects then exercised 5 to 6 days per week at 80% ST heart rate (HR) until voluntary peak exertion without symptom exacerbation. Treadmill testing was repeated every 3 weeks. Adverse reactions to exercise, PCS symptoms, HR, systolic blood pressure (SBP), achievement of maximal exertion, and return to work/sport. Pretreatment, ST occurred at low exercise HR (147 + or - 27 bpm) and SBP (142 + or - 6 mm Hg). After treatment, subjects exercised longer (9.75 + or - 6.38 minutes to 18.67 + or - 2.53 minutes, P = .001) and achieved peak HR (179 + or - 17 bpm) and SBP (156 + or - 13 mm Hg), both P < .001 versus pretreatment, without symptom exacerbation. Time series analysis showed significant change in rate of symptom reduction for all subjects and reduced mean symptom number in 8/11. Rate of PCS symptom improvement was related to peak exercise HR (r = -0.55, P = .04). Athletes recovered faster than nonathletes (25 + or - 8.7 vs 74.8 + or - 27.2 days, P = .01). No adverse events were reported. Athletes returned to sport and nonathletes to work. Treatment with controlled exercise is a safe program that appears to improve PCS symptoms when compared with a no-treatment baseline. A randomized controlled study is warranted.
In spite of several calls for increased use of single-subject designs for evaluating applied sport psychology interventions, studies using them rarely appear in our major sport psychology journals. On the assumption that some basic misunderstandings concerning these designs may have contributed to their lack of use, the present paper: (a) describes fundamental characteristics of all single-subject designs, (b) attempts to clarify potential misunderstandings concerning these designs, and (c) describes the alternating-treatments design—a strategy for comparing two or more treatments on an ongoing basis within individual athletes.
Post-concussion symptoms (PCS) (such as headaches, irritability, anxiety, dizziness, fatigue and impaired concentration) are frequently experienced by patients who have sustained a minor head injury (MHI). The post-concussion syndrome has been defined as a clinical state where 3 or more symptoms persist for more than 3 months. This report focuses on the quantification of PCS according to the Rivermead Postconcussion Symptoms Questionnaire (RPQ). We studied 100 consecutive patients with MHI and normal computed tomography of the brain. At 3 months after injury, 62% reported the presence of one or more symptoms, and 40% fulfilled the diagnostic criteria for post-concussion syndrome. Patients with post-concussion syndrome had significantly (P < 0.001) higher RPQ scores (mean 19.1, SD 11.9) than those without (mean 1.2, SD 1.8). Patients on sick leave owing to the injury reported significantly (P = 0.05) higher RPQ scores (mean 10.3, SD 13.2) than those not on sick leave (mean 5.5, SD 8.6). We observed no association between age, gender, cause of injury, severity of injury, duration of amnesia and RPQ score. RPQ score provides useful information about the severity of PCS regardless of whether the diagnostic criteria for the post-concussion syndrome are met or not.
Calculation of integer heart rate variability (HRVi) permits monitoring over extended periods. We asked whether continuous monitoring of HRVi or integer pulse pressure (PP) variability (PPVi) could predict intracranial hypertension, defined as ICP >20 mm Hg, cerebral hypoperfusion, defined as CPP<60 mm Hg, mortality or functional outcome after severe traumatic brain injury. Dense integer data collected during continuous intensive care unit monitoring for periods of 1 to 11 days on 25 patients admitted to our Level I trauma center with Glasgow Coma Scale <9 provided 1,715,000 data points over a mean 106±62 hours. PP, HRVi, and PPVi increased in response to increasing ICP when CPP >60 mm Hg (P<0.001), but HRVi and PPVi decreased when CPP <60 mm Hg and P<50 mm Hg, even with ICP <20 mm Hg (P<0.001). ICP up to 40 mm Hg still evoked an increase in HRVi and PPVi (P<0.001), but both were suppressed with CPP <50 mm Hg and ICP >40 mm Hg (actual or impending brain death). Mean HRVi and PPVi predicted in-hospital mortality (sensitivity, 67%; specificity, 91% to 100%). Combining HRVi and PPVi as an "autonomic index" (AI) best predicted long-term functional outcome [Area Under the Curve: 0.84±0.08 for AI <0.5]. Our data show that HRVi and PPVi can be monitored and calculated automatically and can provide useful prognostic information in patients with severe traumatic brain injury, particularly when combined into a single index.