• Clinical Psychopharmacology and Neuroscience
• /
• v.16 no.4
• /
• pp.481-488
• /
• 2018

Preliminary studies have claimed that short term fasting would negatively affect school performance and cognition. In contrast some other studies have reported not important decline in cognition and executive function as a result of fasting. Also limited attention was generally devoted to dietetic regimens, nutritional status and body weight. Yet neuroscience and neuro-cognitive aspects of acute hunger on the electroencephalogram and differences between obese and non-obese cases is not well understood. Hence, we decided to design and perform a case study in a more controlled situation similar to reality. Therefore, we performed several examinations including subjective tests (for eating status) and objective tests (cognitive tests such as Stroop effect and Sternberg search and electroencephalogram measures such as steady-state visual evoked potential and auditory steady-state responses) for an obese and a non-obese academic case before and after a simple breakfast. The results showed that the breakfast effects on the neuro-cognitive functions depend on either obesity status, nutritional status of the case or the type of cognitive task (visual or auditory). This paper would open a new insight to answer some important questions about the neuro-cognitive implications of fasting and feeding in obese and non-obese human cases.

• Phonetics and Speech Sciences
• /
• v.1 no.4
• /
• pp.203-207
• /
• 2009

Electrically evoked compound action potentials (ECAP) have originated from the distal end of the auditory nerve. ECAP are characterized as the difference between the clearly large trough (N) and the following positive peak (P). N-wave occurs around $200-400\;{\mu}s$ after stimulus onset and P-wave at around $400-800\;{\mu}s$. Contrary to expectations, positive peaked ECAP (pp-ECAP) was dominated by a relatively large-amplitude positive following negative peak. pp-ECAP can be recorded from the sites on or near the surgically exposed nerve trunk in animal models and/or in cases of monophasic stimulation. This study will provide the causes of the appearance of pp-ECAP in cases of cochlear implant recipients using imaging studies and medical records and statistically analysis between N-P and P-N on the amplitude input-output function (amp-I/O) for the prediction of the possibilities of clinical tools. Thirteen children participated in the study and received a Cochlear CI-24RE (CA). ECAP was recorded using auto-NRT (Cochlear Ltd., Australia) at four to five weeks post surgery. pp-ECAP was measured from 36 electrodes and typical ECAP from 220 electrodes. There was no abnormality in the imaging study and operation finding in patients with typical ECAP. pp-ECAP was found at the inner ear anormaly and ossification in imaging study and gel-state inner ear fluid was observed in the operation finding. The amplitude of pp-ECAP increased depending on current intensities, but amp-I/O increase more gradually than in the case of typical ECAP (p=0.003). pp-ECAP is antidromic potential which can record from the inner ear anormaly and ossified cochlear. Amp-I/O also depends on current intensity as well typical ECAP. These results provide a useful tool for audiological evaluation for the spiral ganglion cell status to the value of pp-ECAP.

• Clinical and Experimental Pediatrics
• /
• v.49 no.12
• /
• pp.1308-1314
• /
• 2006

Purpose : This study aimed to evaluate the usefulness of auditory evoked potential (AEP) in clarifying neuronal development in premature small for gestational age (SGA), and appropriate for gestational age (AGA) infants. Methods : A total of 183 premature infants who were born from August 2002 to July 2005, were examined with AEP. They were divided into three groups; AGA, symmetric-SGA and asymmetric-SGA group. Results : Statistically significant differences in the head circumference were observed in three groups. Among the risk factors, prevalence of hypoglycemia and hypoalbuminemia between AGA and asymmetric SGA infants were significantly different. V absolute peak latency (APL) in the right side of AGA infants was delayed were than that of asymmetric SGA infants. III-V interpeak latency (IPL) of asymmetric SGA infants was delayed more than that of symmetric SGA infants. Moreover, I-V IPL on both sides of symmetric SGA infants was shortened more than that of AGA infants. However, all the results of AEP were within the reference range, according to gestational age. Birth weight of, only asymmetric SGA, was related to the III APL on both sides and the III-V IPL on right side. Conclusion : This study shows that the values of APL and IPL of premature SGA infants are different than that of premature AGA infants. These data could be an indicator in evaluating the neurologic functions of small for gestational age infants.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.269-273
• /
• 1999

Combination of mental stress task with noise background is a traditional tool employed in psychophysiology. However, intensity of background noise is a factor affecting both performance on test and psychophysiological responses associated with stress evoked by mental load in noisy environment. In the current study on 7 subjects we analyzed the influence of white noise (WN) intensity (55, 70, and 85 dB[A] ) on psychophysiological responses during word recognition test performed on noise background. There were recorded following physiological variables: electrodermal activity (EDA) , namely, skin conductance level (SCL), skin conductance response (SCR) amplitude (SCR-A), rise time and total number of SCRs (N-SCR); cardiovascular activity, e.g., heart rate (HR), respiratory sinus arrhythmia (RSA) index, pulse transit time (PTT), finger pulse volume (PV), skin temperature (SKT) and respiratory activity, such as respiration rate (RESP-R) and inspiration wane amplitude (RESP-A) during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different WN intensity (55, 70, and 85 dB). Electrodermal responses (SCR-A, SCL, N-SCR) demonstrated gradual increment with increased intensity of noise, and this increase of response magnitude with higher intensity of noise was typical also for r skin temperature (phasic SKT decrease) and pulse volume (phasic and tonic PV decrease). However, some cardiovascular and respiratory responses did not exhibit same tendency of gradual increase of reactivity , namely HR, as well as RESP-R and RESP-A showed decrement of response magnitudes. Important finding in terms of cardiovascular reactivity was that 55 and 70dB evoked similar profiles, while 85dB WN resulted in significantly different profile of reactions, suggesting that there exists a threshold level after which intensive auditory stimulation elicits psychophyslological responses pattern of different quality. There are discussed potential autonomic mechanism involved in mediation of observed physiological responses.

• Korean Journal of Biological Psychiatry
• /
• v.19 no.3
• /
• pp.115-120
• /
• 2012

Objectives : Event-related potentials have been suggested as an objective marker for brain functions in psychiatric disorders. This study was aimed to investigate the relationships between P300, the mismatch negativity (MMN), the loudness dependence of the auditory evoked potential (LDAEP), demographic and clinical variables including neurocognitive abilities in patients with schizophrenia. Methods : P300, the MMN, and the LDAEP were measured and the Korean Stroop color-word test (K-stroop test) and the Wisconsin Card Sorting Test (WCST) were performed in 43 patients with schizophrenia. The relationship of the latency and amplitude of P300 and the MMN as well as regression slope of the LDAEP with demographic and clinical variables were analyzed by t-test and correlation analyses for categorical and continuous variables, respectively. Results : After controlling for age, the latency of central (Cz) and parietal (Pz) P300 posivitively correlated with GAF at admission (Cz ; ${\gamma}$ = 0.385, p = 0.047, Pz ; ${\gamma}$ = 0.421, p = 0.029). The amplitude of parietal P300 correlated with the correction rate of the K-stroop test (${\gamma}$ = 0.575, p = 0.002). In addition, the frontal (Fz) P300 latency tended to negatively correlated with the correction rate of the WCST (${\gamma}$ = -0.371, p = 0.057). Conclusions : Our findings suggest that the values of P300 latency and amplitude might be correlated with GAF at admission and working memory measured by the K-Stroop test and the WCST. Meanwhile, the MMN and the LDAEP did not correlate with demographic and clinical variables. These results support the results of previous studies showing associations with P300 and impaired cognitive ability.

• Proceedings of the KOSOMBE Conference
• /
• v.1995 no.11
• /
• pp.147-150
• /
• 1995

최근의 마취과학에 관한 연구에 있어서의 주된 경향은 마취심도 및 의식수준의 결정을 신경생리학적인 관점에서 분석하고자 하는 것이다. 즉, 마취와 의식에 관한 인간의 뇌가 가지고 있는 기능이나 약리학적인 반응을 대표할 수 있는 생체신호를 검출, 분석하여 정량화하고 이들을 이용하면 마취심도 및 의식수준과의 큰 상관관계를 얻을 수 있을 것이라 가정하는 것이다. 본 연구에서는 청각유발전위 (LAEP, Long latency Auditory Evoked Potential)를 검출하여 추출된 변수들과 마취제 투여량간의 변화에 따른 상관성을 분석하고자 하였다. 수술환자(17명)를 대상으로 실험을 실시하였으며 마취제로서는 Midazolam과 Diazepam을 인체로 투여하고 1 KHz와 2 KHz의 청각자극을 제시하였을 때 피검자로부터 발생되는 LAEP를 검출하였다. 검출된 LAEP로부터 추출된 N100과 P300의 진폭은 마취량의 증가에 따라서 간소함을 알 수 있었으며, 이러한 유의한 상관성을 보이는 진폭의 변화는 마취제의 투여에 따른 의식수준의 변화를 나타내는 지수(index)의 설정 및 알고리듬의 수립에 이용될 수 있을 것이다.

• Journal of Korean Neurosurgical Society
• /
• v.39 no.3
• /
• pp.183-187
• /
• 2006

Objective : Hemifacial spasm has characteristic and specific electrophysiological finding, lateral spread response[LSR]. We study the correlation between change of lateral spread response during microvascular decompression[MVD] and clinical outcome after MVD. Methods : Sixty two patients with hemifacial spasm who were treated with microvascular decompression from March 2000 to February 2003 were included in this study. The monitoring of intraoperative facial electromyography[EMG] and brain stem auditory evoked potential were performed. Results : In 28 [44.7%] patients, there was persistence of lateral spread response after vascular decompression in root exit zone of facial nerve. Among these 28 patients, 9 had mild hemifacial spasm at discharge. Three out of 34 patients who had intraoperative disappearance of lateral spread response after MVD had mild hemifacial spasm. But Both groups, disappearance of LSR [Group I], and persistence [Group II] had only 2 patients with mild hemifacial spasm, and 5 patients at 3 months, respectively. Conclusion : Although intraoperative EMG monitoring is very useful in assessing the efficacy of MVD, the clinical outcome of MVD in patient with hemifacial spasm does not always correlate with EMG finding. The prognostic value of intraoperative LSR monitoring in the long-term results is questionable.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.2
• /
• pp.15-21
• /
• 2009

Hearing loss is one of the most common birth defects among infants. Most of hearing-impaired children are not diagnosed until 1 to 3 years of age - which is too late for the critical period (6 month) for normal speech and language development. If a hearing impairment is identified and treated in its early stage, child's speech and language skills could be comparable to his or her normal-hearing peers. For these reasons, hearing screening at birth and throughout childhood is extremely important. ABR (Auditory brain-stem response) is nowadays one of the most reliable diagnostic tools in the early detection of hearing impairment. In this study, we have developed the system that automatically detects if there is hearing impairment or not for infants or children. For future studies, it will be developed as a portable system to be able to take a measurement not only in sound proof room but also in nursery for neonates.

• Clinical and Experimental Pediatrics
• /
• v.52 no.3
• /
• pp.289-294
• /
• 2009

Purpose : To assess the usefulness of magnetic resonance imaging (MRI), karyotyping, brainstem auditory evoked potential (BAEP), electroencephalogram (EEG), tandem mass screening test, and newborn metabolic screening test in children with language delay for diagnosing underlying diseases. Methods : From January 2000 to June 2007, a retrospective chart review was performed for 122 children with language delay who visited the Child Neurology Clinic at Yeungnam University Hospital and who underwent neuropsychologic tests and other diagnostic evaluations for underlying diseases. They were grouped into phenomenological diagnostic categories, and test results were analyzed according to the underlying diseases. Results : Of 122 patients, 47 (38.5%) had mental retardation, 40 (32.8%) had developmental language disorders, 23 (18.9 %) had borderline IQ, and 12 (9.8%) had autism spectrum disorder. In 26 (21.3%) cases, the causes or relevant clinical findings to explain language delay were found. Eight (10.4%) of 77 MRIs, 6 (8.0%) of 75 EEGs, and 4 (5%) of 80 BAEPs showed abnormal results. Results directly attributed to diagnosing underlying diseases were 2 hearing defects in BAEPs and 1 bilateral perisylvian cortical dysplasia in MRIs. No abnormal results were found in karyotyping, tandem mass screening tests, and new-born screening tests. Conclusion : Commonly used tests to diagnose the cause of language delay are not very effective and should only be used selectively, according to patient characteristics. However, despite the low diagnostic yields from these tests, because many patients show abnormal results, these tests are useful when conducted in complete evaluation.