hemoencephalography
Research Papers
Neural correlates in functional brain mapping among breast cancer survivors receiving different chemotherapy regimens: a qEEG/HEG-based investigation
BACKGROUND: Post-chemotherapy cognitive impairment commonly known as 'chemobrain' or 'chemofog' is a well-established clinical disorder affecting various cognitive domains including attention, visuospatial working memory, executive function, etc. Although several studies have confirmed the chemobrain in recent years, scant experiments have evaluated the potential neurotoxicity of different chemotherapy regimens and agents. In this study, we aimed to evaluate the extent of attention deficits, one of the commonly affected cognitive domains, among breast cancer patients treated with different chemotherapy regimens through neuroimaging techniques. METHODS: Breast cancer patients treated with two commonly prescribed chemotherapy regimens, Adriamycin, Cyclophosphamide and Taxol and Taxotere, Adriamycin and Cyclophosphamide, and healthy volunteers were recruited. Near-infrared hemoencephalography and quantitative electroencephalography assessments were recorded for each participant at rest and during task performance to compare the functional cortical changes associated with each chemotherapy regimen. RESULTS: Although no differences were observed in hemoencephalography results across groups, the quantitative electroencephalography analysis revealed increased power of high alpha/low beta in left fronto-centro-parietal regions involved in dorsal and ventral attention networks in the Adriamycin, Cyclophosphamide and Taxol-treated group compared with the Taxotere, Adriamycin and Cyclophosphamide and control group. The Adriamycin, Cyclophosphamide and Taxol-treated cases had the highest current source density values in dorsal attention network and ventral attention network and ventral attention network-related centers in 10 and 15 Hz associated with the lowest Z-scored Fast Fourier Transform coherence in the mentioned regions. CONCLUSIONS: The negatively affected neurocognitive profile in breast cancer patients treated with the Adriamycin, Cyclophosphamide and Taxol regimen proposes presumably neurotoxic sequelae of this chemotherapy regimen as compared with the Taxotere, Adriamycin and Cyclophosphamide regimen.
View Full Paper →Evaluating Prefrontal Activation and Its Relationship with Cognitive and Emotional Processes by Means of Hemoencephalography (HEG)
The main aim of this study is to determine the efficacy of the method of diagnosis known as hemoencephalography (HEG), which measures hemodynamic changes in the prefrontal cortex by determining differences in oxygen flow to show patterns of neuronal activity. Of the 5 tests designed for this purpose, 2 are strictly cognitive, while the other 3 have primarily emotional or sensitive content. The tests were applied to a sample of 70 university students. The Wilcoxon nonparametric signed rank test was applied to test the paired differences between the HEG baseline result and the HEG result of the task. Results show, first, that the HEG method successfully determines oxygen flow to the prefrontal cortex and clearly differentiates the subject's baseline from HEG activation during the task (Wilcoxon, p < .05); second, that HEG results vary depending on the type of activity, whether cognitive (low emotional load) or emotional (high emotional load) in such a way that cognitive areas, those located higher in the cortex (dorsolateral prefrontal), show less activity during emotional tests and more activity during cognitive tests, thus associating higher areas (dorsolateral prefrontal) with cognition and deeper areas (medial temporal, medial prefrontal, and cingulate) with emotion. The HEG procedure is effective in detecting states or situations of ailment or suffering not always accompanied by evident external manifestations. Furthermore, the procedure can differentiate between cognitive and emotional processing. The HEG method can help diagnosis in clinical settings due to its ability to detect painful-feeling processing independently of both body and verbal language.
View Full Paper →Effects of Hemoencephalographic (HEG) Training at Three Prefrontal Locations Upon EEG Ratios at Cz
Background. Light in the wavelength region of 650 to 1000 nanometers is able to penetrate living human tissue, including bone. Medical research has exploited this optical window into the body to develop non-invasive monitoring of brain functioning. In 1994 Herschel Toomim discovered that he could both measure and teach persons to control the amount of oxygenated blood flowing in the prefrontal regions with such an optical device. He has labeled the biofeedback of brain blood flow hemoencephalography (HEG). Methods. A fifteen-year-old male with a history of mild articulation problems and poor spelling was administered twenty sessions of combined HEG/EEG biofeedback, with a referential recording at Cz. Feedback in each session was conducted in three trials with the HEG optodes placed over the left eye, at midline, and over the right eye for ten minutes each. The order of placement was counterbalanced across trials. Changes in HEG levels within each trial were computed and plotted across sessions, as was the theta/beta ratio for each trial. Results. The subject clearly learned improved voluntary control over brain blood flow. The slope of increases of HEG within each trial improved across sessions at all three forehead locations. There were three indications from this case that HEG training to improve attention might be most efficacious at the midline location: (a) the theta/beta ratio at Cz decreased slightly over sessions only in response to HEG training at midline, (b) bursts of beta lasting ten seconds or more occurred more often, and (c) occasionally a marked increase in HEG within a trial was associated with a corresponding increase in power in beta. This occurred only with HEG at midline. Conclusion. HEG biofeedback is a promising treatment modality, especially for improving the functioning of executive control systems mediated by the prefrontal regions of the cerebral cortex.
View Full Paper →Hemoencephalography–A New Therapy for Attention Deficit Hyperactivity Disorder (ADHD): Case Report
Background. Hemoencephalography (HEG) is cortical circulatory biofeedback using refracted light tuned to oxygenated hemoglobin, emitted into the skull and detected at the scalp using a photoelectric cell. Red light at 660 nm is used as the probe, with changes in the returning refracted light representing changes in cortical circulation. Method. A single-subject design case study was employed. TL, at age twelve, had a well-established diagnosis of ADHD given by pediatric neurologists, and required significant stimulant medication that was clinically effective. He was performing well in school on Concerta 36 mg at 7 a.m. and Ritalin 5 mg at 4 p.m. Off medication, he had significant abnormalities on IVA testing (Attention Quotient or AQ = 78) and in the quantitative electroencephalogram (QEEG). Using HEG, the patient engaged the system to exercise increases in signals corresponding to cortical circulation in the prefrontal cortex. QEEG, Continuous Performance Testing (CPT) and clinical status measurements were made before and after 10 sessions of HEG therapy. HEG exercise was typically given in weekly to bi-weekly sessions for 10 minutes in each of three standard prefrontal EEG locations: FP1, FP2 and FPz. Results. During the 10 therapy sessions TL's HEG data showed positive gain indicating success at raising the biofeedback signal. Following the 10 sessions, TL showed a normal QEEG with improved Z scores for relative power and normal IVA testing off medication (mean AQ 99.75 ± 7.85 on three dates), which persisted in the 18-month follow-up. His medication was lowered to Focalin 2.5 mg twice daily. Conclusion. This work documents a patient who showed clinically significant improvement after only 10 sessions using a new form of neurobiofeedback, hemoencephalography. If confirmed in controlled studies, this represents a breakthrough in treatment options for ADHD. Future studies should explore synergies between HEG and EEG neurofeedback therapies.
View Full Paper →Intentional Increase of Cerebral Blood Oxygenation Using Hemoencephalography (HEG): An Efficient Brain Exercise Therapy
Intentional enhancement of regional cerebral blood oxygenation (rCBO2) in specific cerebral locations was studied as a brain exercise. A review of literature showed the effect of brain exercise on brain physiology. Hemoencephalography (HEG), a graphic analog of brain blood flow of oxygenated hemoglobin indicated by non-invasive infrared spectroscopy, was used to guide intentionally increasing rCBO2. A musical note and visual graphic keyed to changes in cortical blood oxygenation was provided to the participant. A primary aim of this study was to demonstrate the capacity of subjects with brain disorders to increase oxygenation of selected brain tissue using HEG and test the hypothesis that multiple repetitions of these brain exercises improved sustained attention measured with a continuous performance test. The impulsivity score for subjects in the exercise group was in the normal range after 10 sessions. In a small set of subjects, low arousal SPECT images showed increased vascularity after 30 half-hour sessions of intentional enhancement of local blood oxygenation.
View Full Paper →Passive Infrared Hemoencephalography: Four Years and 100 Migraines
Background. One hundred migraine sufferers were treated using passive Infrared Hemoencephalography (pIR HEG) over a period of four years. All subjects met the criteria for at least one of the categories set forth in the International Headache Society (IHS, 1988) classification criteria for headache disorders for primary migraine. Methods. Subjects were treated using the pIR HEG system in 30-minute sessions. A central forehead placement (approximately Fpz) was used for the sensor assembly for all subjects. Changes in headache patterns were examined. After two years, an infrared video imaging system was added to the data collection process and was available for 61 of the 100 subjects. Infrared forehead images were captured at the start and end of each session to examine changes in prefrontal cortical brain activity. Results. Most of the subjects improved control over their migraine headaches. Over 90% of those subjects who completed at least six sessions reported significant improvements in migraine activity. Conclusions. pIR HEG appears to have a strong impact on migraine headaches, even for people who have not had a positive response to medication. Headache response by the end of six sessions appears to be a good predictor of probability of improvement
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