• Sleep Medicine and Psychophysiology
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• v.12 no.2
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• pp.117-121
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• 2005

Objectives: The purpose of this study was to assess the difference of subjective daytime sleepiness level between primary insomnia patients and healthy control subjects. We also investigated the relationship between subjective daytime sleepiness level and variables of nocturnal polysomnograghic sleep architecture of insomnia patients. Method: Total subjects were 87 patients with primary insomnia diagnosed with polysomnography and 88 normal controls. The daytime sleepiness level in each group was measured by Korean version of Epworth Sleepiness Scale (ESS). The correlations of ESS score and nocturnal polysomnographic variables were calculated in the patient group. Results: Patients with insomnia had the lower ESS scores than the control group. In patients group, the ESS score showed significant negative correlations with total sleep time, sleep efficiency%, and stage 2 sleep time%. The ESS score also showed significant positive correlations with number of awakenings, number of awakenings more than 2 minutes, and wake after sleep onset time. Conclusions: Insomnia patients showed lower level of subjective daytime sleepiness that may indicate their higher alertness comparing to control subjects. Daytime sleepiness of patients with insomnia was associated with polysomnographic variables including total sleep time, sleep efficiency%, stage 2 sleep time% and disrupted continuity of nocturnal sleep.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.111-117
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• 2007

The visual evoke potential(VEP) is the effective method to diagnose and treat the amblyopia or to check the infants visual ability. In order to evaluate the changes of P100 latencies and amplitudes of VEP by intensity of illumination and refractive errors, we measured latencies and amplitudes of 41 normal adults (20/20 VA) who have no ocular diseases and neurologic diseases. The results were as follows: In the scotopic condition, the latencies were N75$75.83{\pm}3.69$ msec, P100$103.48{\pm}5.34$ msec, the P100 amplitude was $14.86{\pm}2.43$ msec, and in the photopic condition, the latencies were N75$76.71{\pm}3.11$ msec, P100$107.26{\pm}5.54$ msec and the P100 amplitude was $10.35{\pm}1.75$ msec. The latencies and amplitudes of P100 in the photopic condition had higher values than those in the scotopic condition and the measures were significantly different between the scotopic and photopic condition (p<0.01). The P100 latencies were delayed both in the scotopic and photopic condition with the refractive errors and those measures were delayed more than in the photopic condition. The P100 amplitudes in the induced myopic and hyperopic conditionsreduced than in the emmetopes in both illumination conditions. The P100 latencies and amplitudes in emmetropes showed a correlation with the induced myopic conditions in the scotopic condition. Those results showed that P100 latencies and amplitudes are dependent on the illumination conditions and refractive errors. And we suggest that those results would be useful to determine and evaluate the normal range for the person considering patients' refractive errors and illumination of the test room.

• Korean Journal of Psychosomatic Medicine
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• v.11 no.2
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• pp.196-204
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• 2003

Objectives: It is known that sedative hypnotics would make cross tolerance with alcohol and deteriorate quality of sleep in alcoholics. Light therapy is effective non-pharmacological intervention for sleep disturbance in circadian phase disorders, jet-lag, shift-work and age-related sleep disorders. Authors would investigate the effects of morning light therapy on sleep of patients with alcohol dependence during recovery state without withdrawal symptoms. Methods: 13 patients with alcohol dependence who have not any alcohol withdrawal symptom were recruited. Light therapy during 1 hour in the morning had been administered by 2500 Lux light box through serial 3 days. Sleep state of subjects were assessed by sleep log and the subjective satisfaction at sleep was by 100 mm visual analogue scale. Sleepiness, depressive mood, anxiety were evaluated by 100mm visual analogue scale at 8 AM, 2 PM and 8 PM. For assessment of performance ability that would be associated with sleepiness and vigilance, trail making test A, B and digit symbol substitution test were performed by two times on base line and 4th day. Univariate repeated-measures ANOVAs were performed for each measures except performance tests which were analysed by paired t-test. Results: Sleep latency and sleep efficiency were significantly improved with light therapy and satisfaction at sleep was. There was no significant difference in sleepiness at 2 PM with light therapy but sleepiness at 8 AM significantly decreased and at 8 PM increased. The time to complete Trail making test and digit symbol substitution test were significantly shortened at 4th day compared with baseline. Fatigue at 8 AM were not significantly changed with light therapy but at 2 PM and 8 PM significantly decreased. Depressive mood and anxiety were not significantly changed with light therapy. Conclusion: Although this study had some limitations, it showed that light therapy would be effective modality on sleep disturbance of patients with alcohol dependence who have recovered from alcohol withdrawal symptoms. It is proposed that short term light therapy could be used clinically for alcoholics with insomnia. In the future, long term controlled studies using more objective tools for sleep are required to further investigate the effect of light therapy in alcoholics.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.459-467
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• 2009

Purpose: The maximum likelihood-expectation maximization (ML-EM) is the statistical reconstruction algorithm derived from probabilistic model of the emission and detection processes. Although the ML-EM has many advantages in accuracy and utility, the use of the ML-EM is limited due to the computational burden of iterating processing on a CPU (central processing unit). In this study, we developed a parallel computing technique on GPU (graphic processing unit) for ML-EM algorithm. Materials and Methods: Using Geforce 9800 GTX+ graphic card and CUDA (compute unified device architecture) the projection and backprojection in ML-EM algorithm were parallelized by NVIDIA's technology. The time delay on computations for projection, errors between measured and estimated data and backprojection in an iteration were measured. Total time included the latency in data transmission between RAM and GPU memory. Results: The total computation time of the CPU- and GPU-based ML-EM with 32 iterations were 3.83 and 0.26 see, respectively. In this case, the computing speed was improved about 15 times on GPU. When the number of iterations increased into 1024, the CPU- and GPU-based computing took totally 18 min and 8 see, respectively. The improvement was about 135 times and was caused by delay on CPU-based computing after certain iterations. On the other hand, the GPU-based computation provided very small variation on time delay per iteration due to use of shared memory. Conclusion: The GPU-based parallel computation for ML-EM improved significantly the computing speed and stability. The developed GPU-based ML-EM algorithm could be easily modified for some other imaging geometries.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.385-396
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• 2001

The purpose of this experiment was to examine the histological changes and the pattern of expression of proliferating cell nuclear antigen(PCNA) and type I collagen in the elongated bone affected by osteodistraction of the mandibular body in an adult canine model. Seven adult male mongrel dogs weighing over 20kg were used for this experiment. The author excluded 3 animals because they died before the planned time of sacrifice. The custom-made linear extraoral device and 4 bicortical fixation screws 2.3mm in diameter, 50mm in total length, 15mm in screw length were used in each animal. The distal part of the distractor produced a 0.75mm gap between proximal and distal bony segments every $360^{\circ}$ turn of the rotation rod of the device. The mandibular body of the right side from each animal was experimental side and the left side was left intact and served as control. At the experimental side, the mandibular body was osteotomized. After 5-day latency period, the segments were distracted with a rate of 1.1mm/day and a rhythm of two/day for ensuing 7 days. The animals were sacrificed at the 4th. 17th, and 32th day after the end of the distraction. The bony specimens were decalcified, embedded in paraffin, sectioned $5{\mu}m$ thick and stained with Masson trichrome and examined under the light microscope. The immunohistochemical examinations using anti-PCNA antibody and anti-type-I collagen antibody were performed to examine the pattern of the expression of PCNA and type I collagen, respectively. Results : 1. The mean increment of the distance between the proximal and distal screw-holding parts of the distractor was 6.8mm. The average elongation of the mandible in the experimental side was 5.3mm. The loss of elongation was 1.5mm in average. 2. New bone was already observed at the 4th. day after the end of distraction. But, bony union was not completed in the distraction gap at the 32th. day after the end of distraction by radiographic and microscopic examinations. 3. The expression rate of PCNA positive cells in the distraction gap had a tendency of decrease from 35.1-68.8% initially, to 49.1%, and finally to 17.6-27.2%. But at the final period, the tissue of the elongated gap still had the ability of cell proliferation. On the other hand, the expression of PCNA positive cells in the control side were negligible through the experimental period. 4. PCNA positive cells were observed primarily both at the central fibrous zone and at the region of just adjacent to CFZ which initiated new bone formation. 5. The expression pattern of the type I collagen was not zone-specific. They were observed diffusely throughout the elongation gap. 6. The predominant mechanism of new bone formation in the distraction gap was intramembranous. But, some of the regenerated bone was formed by endochondral ossification.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.418-428
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• 2020

The aim of this study was to investigate the effect of resistance exercise(RE) on beta-amyloid(Aβ) metabolism, neuronal cell death, and cognitive function in the transgenic mice model of Alzheimer's disease(AD). Fourteen transgenic(tg) mice and fourteen non-transgenic(non-tg) mice were divided into four groups: (1)non-tg-control(NTC, n=7) (2)non-tg-RE(NTRE, n=7) (3)tg-control(TC, n=7), and (4)tg-RE(TRE, n=7). The groups with RE were performed to progressive RE on ladder equipment for 8 weeks. The groups with RE were performed to progressive RE on ladder equipment for 8 weeks. After then, the cognitive function was measured by using the water maze test, and Aβ metabolism-related proteins, neuronal cell death, and SIRT1/PGC-1α pathway were also measured. Here, we found escape latency and time were significantly increased in the TC compared to the NTC group, but it was significantly reduced in the TRE group, indicating RE may ameliorate cognitive dysfunction. Next, we found an increased in Aβ protein of TC compared to NTC, but it was significantly reduced in the TRE group following RE. In neuronal cell death, Bcl-2 was also significantly decreased and Bax was significantly increased in the TC compared to the NTC group, but RE can increase Bcl-2 and reduce Bax, which may elevate the ratio of Bcl-2/Bax. We further found a decrease in the level of ADAM10 and RARβ protein was significantly increased whereas increased in ROCK1 and BACE1 expression level was significantly reduced following RE in the TRE compared to the TC group. In addition, the level of SIRT1/PGC-1α proteins was decreased in the TC group compared to NTC group, but, these markers were significantly increased in the TRE group following RE. Therefore, our finding indicated that RE may ameliorate cognitive deficits by reducing Aβ protein and neuronal cell death via regulating SIRT1/PGC-1α, amyloidogenic pathway, and non-amyloidogenic pathway, which may play a role in an effective strategy for AD.

• Sleep Medicine and Psychophysiology
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• v.8 no.1
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• pp.30-36
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• 2001

Object: Diurnal variation is included in the diagnostic criteria of the major depressive disorder, melancholic specifier. But there has been controversy over whether diurnal variation is an unique depressive symptoms or a symptom related to a change of sleep patterns, or that of another mechanism, when the previous studies are reviewed. We investigated the existence of diurnal variation according to the subtype of depression and whether diurnal variation is charateristic of melancholic depression or not. We also compared sleep variables according to the existence of diurnal variation. Method: We examined diurnal variation, sleep patterns, severity of depression using the Visual Analogue Mood Scale, Pittsburgh Sleep Quality Index, and Hamilton Depression Rating Scale. Patients recorded their mood state on the Visual Analogue Mood Scale twice a day, morning and evening, for diurnal variation. We divided depressive patients into two groups,-diurnal variation group and nondiurnal variation group,-and compared the mood and sleep variables using SPSS. Results: The frequency of diurnal variation is not significantly different among the subtypes of depression. Significant differences between the diurnal variation group and the nondiurnal variation group existed in middle insomnia and sleep time (p<0.05). In melancholic type, al significant difference between the diurnal variation group and the nondiurnal variation group was noticed in PSQI total, sleep latency, sleep disturbances, daytime dysfunction as well as middle insomnia and sleep time (p<0.05). Conclusions: Diurnal variation existed in other types of depression as well as melancholic type. The results showed that diurnal variation was not a specific symptom of melancholic type, and existence of diurnal variation might be related to sleep patterns.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.121-128
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• 2001

Objectives: In narcoleptic patients diagnosed with ICSD (international classification of sleep disorders, 1990) criteria, nocturnal polysomnography, and MSLT (multiple sleep latency test), we tried to find characteristic features of quantitative electroencephalography (QEEG) in a wakeful state. Methods: We compared eight drug-free narcoleptic patients with sex- and age-matched normal controls, using computerized electroencephalographic mapping technique and spectral analysis. Absolute power, relative power, interhemispheric asymmetry, interhemispheric and intrahemispheric coherence, and mean frequency in each frequency band (delta, theta, alpha and beta) were measured and analyzed. Results: Compared with normal controls, narcoleptic patients showed decrease in monopolar interhemispheric coherence of alpha frequency bands in occipital ($O_1/O_2$), parietal ($P_3/P_4$), and temporal ($T_5/T_6$) areas and beta frequency band in the occipital ($O_1/O_2$) area. Monopolar intrahemispheric coherences of alpha frequency bands in left hemispheric areas ($T_3/T_5$, $C_3/P_3$ & $F_3/O_1$) decreased. Decrease of monopolar interhemispheric asymmetry of delta frequency band in the occipital ($O_1/O_2$) area was also noted. The monopolar absolute powers of beta frequency bands decreased in occipital ($O_2,\;O_z$) areas. Conclusion: Decreases in coherences of narcoleptic patients compared with normal controls may indicate fewer posterior neocortical interhemispheric neuronal connections, and fewer left intrahemispheric neuronal connections than normal controls in a wakeful state. Therefore, we suggest that abnormal neurophysiological sites of narcolepsy may involve complex areas such as neocortex and subcortex as well as the brainstem.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.57-65
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• 1997

As jet lag of modern travel continues to spread, there has been an exponential growth in popular explanations of jet lag and recommendations for curing it. Some of this attention are misdirected, and many of those suggested solutions are misinformed. The author reviewed the basic science of jet lag and its practical outcome. The jet lag symptoms stemed from several factors, including high-altitude flying, lag effect, and sleep loss before departure and on the aircraft, especially during night flight. Jet lag has three major components; including external de synchronization, internal desynchronization, and sleep loss. Although external de synchronization is the major culprit, it is not at all uncommon for travelers to experience difficulty falling asleep or remaining asleep because of gastrointestinal distress, uncooperative bladders, or nagging headaches. Such unwanted intrusions most likely to reflect the general influence of internal desynchronization. From the free-running subjects, the data has revealed that sleep tendency, sleepiness, the spontaneous duration of sleep, and REM sleep propensity, each varied markedly with the endogenous circadian phase of the temperature cycle, despite the facts that the average period of the sleep-wake cycle is different from that of the temperature cycle under these conditions. However, whereas the first ocurrence of slow wave sleep is usually associated with a fall in temperature, the amount of SWS is determined primarily by the length of prior wakefulness and not by circadian phase. Another factor to be considered for flight in either direction is the amount of prior sleep loss or time awake. An increase in sleep loss or time awake would be expected to reduce initial sleep latency and enhance the amount of SWS. By combining what we now know about the circadian characteristics of sleep and homeostatic process, many of the diverse findings about sleep after transmeridian flight can be explained. The severity of jet lag is directly related to two major variables that determine the reaction of the circadian system to any transmeridian flight, eg., the direction of flight, and the number of time zones crossed. Remaining factor is individual differences in resynchmization. After a long flight, the circadian timing system and homeostatic process can combine with each other to produce a considerable reduction in well-being. The author suggested that by being exposed to local zeit-gebers and by being awake sufficient to get sleep until the night, sleep improves rapidly with resynchronization following time zone change.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.25-32
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• 2008

Objectives: A few studies have compared REM sleep-dependent obstructive sleep apnea syndrome (REM-OSA) with sleep stage non-dependent apnea syndrome (SND-OSA). Despite that REM-OSA might be more common in women than men, no studies have examined the probable characteristics of women patients with obstructive sleep apnea syndrome (OSAS). This study aimed at finding out the characteristics of REM-OSA in women by comparing it with SND-OSA. Methods: Fifty-three subjects diagnosed as OSAS (AHI>5 ; AHI : apnea-hypopnea index) with nocturnal polysomnography at the Center for Sleep and Chronobiology of the Seoul National University Hospital between October 2004 and February 2006 were studied. Of them, 44 subjects with OSAS severity of mild (52 and AHI-NR<15 (AHI-R : AHI during REM sleep, AHI-NR : AHI during non-REM sleep). We compared REM-OSA group with SND-OSA as well as the criteria-determined REM-OSA cases with the visually-determined ones. Results: Among 44 subjects, 28 persons (63.6%) turned out to have REM-OSA by our criteria and 24 persons (54.5%) by visual determination. Statistically significant differences (p<0.05) were found between REM-OSA and SND-OSA groups in AHI, hypopnea index, total sleep time, total wake time, sleep efficiency index, percents of stage 1, 2 and REM sleep, and REM latency. Percent of stage REM sleep (%REM) turned out to have influence on AHI ratio (AHI-R/AHI-NR) (B=0.537, p=0.002). REM-OSA was likely to be diagnosed in milder severity of OSAS (${\chi}^2=13.117$, p<0.001) and those with higher %REM (${\chi}^2=11.325$, p=0.001). There was no significant difference between the criteria-determined and the visually-determined cases of REM-OSA. Conclusion: We suggest that REM-OSA and SND-OSA patients be differentiated in terms of pathophysiology and treatment strategies. Visual determination of REM-OSA might be useful as the screening procedure of REM-OSA. Further studies on women with OSAS and REM-OSA need to be done.