Functioning pancreas graft with thromboses of splenic and superior mesenteric arteries after simultaneous pancreas-kidney transplantation: a case report

Graft thrombosis is the most common cause of early graft loss after pancreas transplantation. The grafted pancreas is difficult to salvage after complete thrombosis, especially arterial thrombosis, and graft pancreatectomy is required. We describe a patient presenting with a functioning pancreas graft with thromboses of the splenic artery (SA) and superior mesenteric artery (SMA) after simultaneous pancreas-kidney transplantation (SPK). A 37-year-old woman with a 20-year history of type 1 diabetes mellitus underwent SPK. The pancreaticoduodenal graft was implanted in the right iliac fossa with enteric drainage. A Carrel patch was anastomosed to the recipient's right common iliac artery, and the graft gastroduodenal artery was anastomosed to the common hepatic artery using an arterial I-graft. The donor portal vein was anastomosed to the recipient's inferior vena cava. Four days after surgery, graft thromboses were detected by Doppler ultrasound without increases in the serum amylase and blood glucose levels. Contrast enhanced computed tomography revealed thromboses in the SA, splenic vein and SMA. Selective angiography showed that blood flow was interrupted in the SA and SMA. However, pancreatic graft perfusion was maintained by the I-graft in the head of the pancreas and the transverse pancreatic artery in the body and tail of the pancreas. We performed percutaneous direct thrombolysis and adjuvant thrombolytic therapy. However, we had to stop the thrombolytic therapy because of gastrointestinal hemorrhage. Thereafter, the postoperative course was uneventful and the pancreas graft was functioning with a fasting blood glucose level of 75 mg/dL, HbA1c of 5.1%, and serum C-peptide level of 1.9 ng/mL at 30 months post-transplantation.

Results of a 2011 national questionnaire for investigation of mean glandular dose from mammography in Japan

Diagnostic reference levels (DRLs) for mammography have yet to be created in Japan. A national questionnaire investigation into radiographic conditions in Japan was carried out for the purpose of creating DRLs. Items investigated included the following: tube voltage; tube current; current-time product; source-image distance; craniocaudal view; automatic exposure control (AEC) settings; name of mammography unit; image receptor system (computed radiography (CR), flat panel detector (FPD), or film/screen (F/S)); and supported or unsupported monitor diagnosis (including monitor resolution). Estimation of the mean glandular dose (MGD) for mammography was performed and compared with previous investigations. The MGD was 1.58(0.48) mGy, which did not significantly differ from a 2007 investigation. In relation to image receptors, although no difference in average MGD values was observed between CR and FPD systems, F/S systems had a significantly decreased value compared to both CR and FPDs. Concerning digital systems (FPDs), the MGD value of the direct conversion system was significantly higher than the indirect conversion system. No significant difference in MGD value was evident concerning type of monitor diagnosis for either the CR or the FPD digital systems; however, hard copies were used more often in CR. No significant difference in the MGD value was found in relation to monitor resolution. This report suggests ways to lower the doses patients undergoing mammography receive in Japan, and serves as reference data for 4.2 cm compressed breast tissue of 50% composition DRLs. Furthermore, our findings suggest that further optimisation of FPD settings can promote a reduction in the MGD value.

[A case involving long-term survival following bile duct cancer with para-aortic lymph node metastasis that was treated by multidisciplinary therapy]

Complete resection of advanced bile duct cancer is difficult due to the anatomical location of the tumor and invasion into other organs. Even if a complete resection is achieved, the survival rates of patients with bile duct cancer after surgery are lower as compared to those associated with other gastrointestinal tumors. Certain cases with para-aortic lymph node metastasis have a poor prognosis. In the present report, we describe a case involving long-term survival following bile duct cancer that was treated by multidisciplinary therapy (particle radiotherapy, surgical resection, chemotherapy). In the present case, we detected lymph node (LN) metastasis only in LN#16, but not in LN#13 or LN#17. We believe that particle radiotherapy, consisting of proton and carbon-ion, can be used to control the lymphatic metastasis around the pancreas head and hepatoduodenal ligament. Our findings suggest that particle radiotherapy can be a standard neoadjuvant therapy for bile duct cancer.

18-Fluorodeoxyglucose positron emission tomography does not aid in diagnosis of pancreatic ductal adenocarcinoma

BACKGROUND & AIMS

There are no accurate and reliable tools for diagnosis of early stage pancreatic ductal adenocarcinoma (PDA) or small metastatic lesions. It is also a challenge to differentiate PDA from focal mass-forming pancreatitis (FMP). There is controversy regarding the efficacy of 18-fluorodeoxyglucose positron-emission tomography (FDG-PET) in the diagnosis of PDA. We investigated whether FDG-PET provides information that, combined with data from other imaging techniques, can aid in decision making for patients with suspected PDA.

METHODS

We performed a retrospective analysis of data collected from 232 consecutive patients with suspected PDA at Kobe University Hospital from January 2006 through June 2012. All patients underwent a diagnostic imaging protocol that included multidetector row computed tomography, superparamagnetic iron oxide-enhanced magnetic resonance imaging, and FDG-PET. Based on endoscopic ultrasonography, fine-needle aspiration biopsy, or endoscopic retrograde cholangiopancreatography analyses, 218 patients had PDA (89 underwent resection and 129 did not) and 14 patients had FMP (8 had focal mass-forming chronic pancreatitis and 6 had focal mass-forming autoimmune pancreatitis).

RESULTS

FDG-PET detected 50% of stages 0 and I, 91.9% of stage II, 100% of stage III, and 96.8% of stage IV tumors. Detection was affected significantly by tumor size (P = .024) and T stage (P = .023) in resected tumors. Multidetector row computed tomography detected significantly more liver metastases than FDG-PET. Few para-aortic lymph node or peritoneal metastases were detected by FDG-PET. FDG-PET correctly identified 11 of the 14 patients with FMP (5 of 8 with focal mass-forming chronic pancreatitis and 6 of 6 with focal mass-forming autoimmune pancreatitis).

CONCLUSIONS

FDG-PET is not effective in detecting early stage PDA and small metastases, or in differentiating PDA from FMP. Combining FDG-PET with current diagnostic techniques for PDA did not provide any decisive information, therefore it should not be included in this analysis.

Usefulness of FDG-PET in the evaluation of tumor response to proton beam therapy for locally advanced pancreatic ductal adenocarcinoma

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Background: Evaluation of tumor response to radiation therapy in pancreatic ductal adenocarcinoma (PDA) using conventional radiological tests is difficult due to generally small size and inflammatory or fibrotic changes of radiated tissue. Although increasing evidence has shown that 18-F-fluorodeoxyglucose-positoron emission tomography (FDG-PET) can assess functional changes in various tumors, available data in PDA with radiation therapy is scarce. In this study, we investigated the role of FDG-PET in long-term monitoring tumor response to proton beam therapy (PBT) for PDA. Methods: Thirty-four locally advanced PDA patients with pre- and post-PBT FDG-PET data were included in this study. Local tumor responses by computed tomography (CT) and FDG-PET were defined as below: response group in CT (complete response: CR, partial response: PR, stable disease: SD, progressive disease: PD) was defined according to Response Evaluation Criteria in Solid Tumors, but only evaluation of primary tumor; and in FDG-PET, CR was defined as disappearance of FDG uptake, PR as decrease, SD as unchange, and PD as increase, compared to pre-PBT data. We evaluated tumor response at three different time points: 0-3, 3-6, and 6-12 months after PBT. Also serum CA19-9 values were evaluated. Results: Radiation doses were 50.4-70.2 GyE and 28 (82%) patients received concomitant chemotherapy. During the follow-up period (median 19 months), a total of 90 FDG-PET tests were performed. At the first time point, SD was noted in 90% (9/10) of patients by CT, whereas CR or PR in all by FDG-PET. At the second point, 39% (7/18) of patients demonstrated PR by CT, whereas 91% CR or PR by FDG-PET. Two patients with PD by FDG-PET were diagnosed as SD by CT, while one patient with PD by CT was diagnosed as PR by FDG-PET. At the third point, four patients with PD by FDG-PET were diagnosed as PR or SD by CT. Serum CA19-9 values supported FDG-PET findings. In four of 14 patients with serial FDG-PET, the maximum effects were noted at the second point. Conclusions: Serial FDG-PET can detect changes in local tumor response to PBT for PDA earlier and more sensitively than CT. Of note, there is the risk for false positive in early post-PBT FDG-PET.

[Three cases of recurrent bile duct cancer diagnosed and treated by double-balloon endoscopy]

Local recurrences often develop after the resection of bile duct cancer. Imaging modalities do not have sufficient sensitivity or specificity to enable the definite diagnosis of recurrent bile duct cancer, and it may be difficult to decide when to start chemotherapeutic treatment. It is difficult to obtain specimens by conventional endoscopy after Roux-Y biliary reconstruction. The double-balloon endoscope(DBE) has 2 balloons: one at the tip of the endoscope and the other at the over- tube. The 2 balloons are inflated alternately and the endoscope can move through the small intestine in a caterpillar-like manner. DBE simplifies the approach to Roux-Y choledochojejunostomy and to obtaining a pathological specimen. Moreover, endoscopic biliary drainage and cholangiography can be performed with the DBE. Recently, the DBE has enabled systemic chemotherapy to be started after obtaining pathological evidence of malignancy, as well as biliary drainage instead of percutaneous transhepatic biliary drainage in cases with recurrent bile duct cancers. Here, we present 3 cases of recurrent bile duct cancer diagnosed and treated by a DBE.

[A case of postoperative liver metastasis from pancreatic carcinoma treated with percutaneous isolated hepatic perfusion(PIHP)]

We report a case of postoperative liver metastasis arising from pancreatic carcinoma treated with a novel procedure that we developed-percutaneous isolated hepatic perfusion (PIHP). A 69-year-old man diagnosed with pancreatic body cancer(pT3, pN0, pStage III) was treated using distal pancreatectomy and adjuvant therapy with gemcitabine(GEM). Six months later, a metastasis to the medial segment of the liver was found using computer tomography(CT). The patient was treated by chemotherapy with S-1, but the liver metastasis grew, and we therefore employed PIHP as the third-line therapy, using 80 mg doxorubicin (DXR) and 62 mg mitomycin C (MMC). Six weeks after PIHP, the tumor marker carbohydrate antigen 19-9( CA19-9) had decreased from 44,469 to 4,268 U/mL, and the carcinoembryonic antigen(CEA) level decreased from 28.8 to 5.4 U/mL. Although the size of the carcinoma remained the same on CT, some cells had liquefied as a result of necrosis. However, the patient died about 1 year after PIHP due to the growth of liver metastasis, peritoneal metastasis, and local recurrence, reflected by a progressively increasing level of tumor marker. In this case, PIHP seemed to be ineffective due to local recurrence and peritoneal metastasis as well as early enlargement of liver metastasis. However, the reduction in tumor marker levels and the observed tumor necrosis, suggest that PIHP is a potentially effective and promising treatment for liver metastasis arising from pancreatic carcinoma.

[A case of interstitial lung disease associated with gemcitabine treatment in a patient with locally advanced pancreatic cancer following proton beam radiotherapy]

A 69-year-old woman who had locally advanced pancreatic cancer underwent proton beam radiotherapy(67.5 GyE/25 Fr) concurrent with gemcitabine chemotherapy (GEM 800 mg/m2 day 1, 8) at Hyogo Ion Beam Medical Center, followed by GEM chemotherapy (1,000 mg/m2 day 1, 8, 15/28 day)at Kobe University Hospital. She visited our hospital because she was suffering from dyspnea 212 days after first administration of GEM. A chest computed tomography revealed that infiltrations were spreading in the bilateral lung fields. A bronchoscopy showed diffuse alveolar hemorrhage. We diagnosed GEM related interstitial lung disease with diffuse alveolar hemorrhage. We introduced steroid pulse therapy (methylprednisolone 1 g/day) for 3 days followed by oral prednisolone (40 mg/day), which was tapered gradually. She recovered and was discharged on the 24th day after admission.

Repeating regional acute pancreatitis in the head of the pancreas caused by intraductal papillary mucinous neoplasms in the tail: report of a case

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a distinct entity characterized by papillary proliferations of mucin-producing epithelial cells with excessive mucin production and cystic dilatation of the pancreatic ducts. The clinical presentation often involves recurrent episodes of pancreatitis associated with the temporal obstruction of the main pancreatic duct caused by the hypersecretion of mucin. We herein describe a case in which the patient repeatedly experienced the occurrence of idiopathic acute pancreatitis in the head of the pancreas over a 9-year period, and who was ultimately was cured by distal pancreatectomy for IPMNs in the pancreatic tail. This case illustrates the potential pitfalls in the diagnosis of IPMNs owing to a discrepancy between the site of pancreatitis and that of the IPMN. The possible mechanisms linking acute pancreatitis with the formation of IPMNs are also reviewed.

Pancreatic volumetric assessment as a predictor of new-onset diabetes following distal pancreatectomy

INTRODUCTION

Pancreatogenic diabetes after pancreatectomy is of growing importance due to the increasing life expectancy of pancreatectomized patients. Although reduction of pancreatic volume is thought to affect glucose metabolism, a consistent relationship has yet to be determined. This study aimed to investigate functional consequences of distal pancreatectomy (DP) in preoperatively non-diabetic patients.

METHODS

This study included 61 non-diabetic patients who underwent DP. Clinical data were obtained, and the percent resected volume (PRV) of each pancreas was determined via multi-detector row computed tomography volumetry.

RESULTS

During the follow-up period (median 26 months), 22 patients (36 %) developed new-onset diabetes within a median onset time of 8 months (range 0.5-42 months) postoperatively. The remaining 39 patients also showed impaired glucose metabolism. Multivariate analysis identified preoperative hemoglobin A1c ≥ 5.7 % (odds ratio 15.6, p = 0.001) and PRV > 44 % (odds ratio 11.3, p = 0.004) as independent risk factors for new-onset diabetes.

CONCLUSIONS

Key determinants of postoperative glycemic control include preoperative functional reserve of the endocrine pancreas and the volume reduction of pancreatic parenchyma. Our findings enable reliable preoperative evaluation of the risk of postoperative diabetes and appropriate postoperative surveillance, which is helpful for early intervention in high risk patients.

[Mucinous cystic neoplasm of the pancreas associated with pregnancy: report of two cases]

Pancreatic neoplasms during pregnancy are rare. We describe two cases of mucinous cystic neoplasm (MCN) associated with pregnancy. A 34-year-old woman in the 26th week of pregnancy was given a diagnosis of MCN measuring 19 cm in diameter. We decided to resect it post partum in consideration of the risk of abortion. She had a healthy infant in the 40th week of pregnancy and three months later, distal pancreatectomy was performed. Pathological analysis revealed a mucinous cystadenoma of the pancreas. The second case was a 36-year-old woman. She was given a diagnosis of MCN, measuring 16 cm in diameter, post partum and distal pancreatectomy was performed. Pathologically, the tumor was an invasive mucinous cystadenocarcinoma of the pancreas. In this report, we did an extensive literature review and discussed the management of MCN during pregnancy with special reference to the timing of the operation and the relationship between tumor growth and sex hormones.

[Case of a sigmoid colon cancer with metachronous metastases of the stomach and the abdominal wall]

We report a rare case of a 73-year-old man with gastric metastasis from colorectal cancer. Tumors of the stomach and the right side abdominal wall were diagnosed by FDG/PET-CT. Upper gastrointestinal endoscopy revealed a submucosal tumor with central depression in the fornix of the stomach. Since sigmoidectomy had been performed for cancer 39 months ago, we suspected metastasis. Proximal gastrectomy and resection of the tumor of the abdominal wall were performed. Histological findings showed moderately differentiated adenocarcinoma in the submucosal tumor. Immunohistochemical studies revealed focal positive staining for CK20 and diffuse for CDX2. These findings were similar to those of his primary sigmoid colon cancer and therefore metastasis was diagnosed.

Restless legs syndrome in hemodialysis patients: health-related quality of life and laboratory data analysis

AIMS

To compare clinical data, sleep quality and health-related quality of life (HRQOL) with and without RLS in HD patients.

MATERIALS AND METHODS

The international RLS study group diagnosis questionnaire was completed by 228 HD patients. The Pittsburg Sleep Quality Index (PSQI) for the evaluation of sleep quality and the Kidney Disease Quality of Life (KDQOL-SF) for the analysis of HRQOL were also used.

RESULTS

53 (23%) patients were diagnosed as RLS. Age and age at the initiation of HD were significantly younger in the RLS group. Serum calcium concentration (Ca) was significantly higher in the RLS group. Sleep quality evaluated by PSQI was significantly lower in the RLS group. In SF-36 domains of KDQOL-SF, bodily pain, general health perceptions, vitality, role functioning emotional, mental health and mental component score were significantly lower in the RLS group. In kidney targeted scales of KDQOL-SF, symptoms/problems, burden of kidney disease, cognitive function, quality of social interaction, sleep and patient satisfaction were significantly lower in the RLS group.

CONCLUSION

High Ca was possibly connected to the pathophysiology of RLS which impaired sleep quality as well as HRQOL including mental health and many kidney disease related scales.

Morphology and gelation of thermosensitive xyloglucan hydrogels

Galactose modified xyloglucan is a thermally reversible hydrogel that is increasingly used in the biomedical field due to the ease of altering the gelation time and temperature by modifying the galactose removal ratio. However there is little information concerning the morphology and rheological properties of the hydrogel under physiological conditions. Differential scanning microcalorimetry (DSmicroC) showed the thermal gelation process to occur over a broad temperature range (5-50 degrees C). The rheological properties of the hydrogels were investigated as a function of concentration, temperature and ionic strength. The final elastic moduli of the hydrogels increased with increases in concentration. Isothermal rheology suggests that the gelation occurred in two distinct stages, which was influenced by the solution media. Scanning electron microscopy (SEM) was used to characterize the morphology of the xyloglucan which were thermally gelled at 37 degrees C. The resultant morphology was strongly dependent on the concentration of the hydrogel. Strong hydrogels were only obtained at 3 wt.% at 37 degrees C, and the morphology characterized by an open 3-dimensional network, comprised of thin membranes. It is proposed that the first stage of the isothermal gelation is the formation and growth of the thin membranes, followed by the formation of a three dimensional network.

Treatment and long-term prognosis of myoclonic-astatic epilepsy of early childhood

PURPOSE

We retrospectively studied patients with myoclonic-astatic epilepsy of early childhood (MAE) to investigate the most effective treatment and long-term seizure and intellectual prognosis.

SUBJECTS

Eighty-one patients with MAE were recruited from among 3600 patients with childhood epilepsy according to the ILAE criteria of MAE.

METHODS

We retrospectively investigated the clinical characteristics and ultimate prognosis of the patients with MAE from the medical records. The effects of various antiepileptic drugs, ketogenic diet and ACTH treatments on myoclonic-astatic seizures (MS/AS), apparently a hallmark of this unique epileptic syndrome, were also studied.

RESULTS

MS/AS in 89 % of the patients disappeared within 1 to 3 years despite initial resistance, but generalized tonic-clonic or clonic seizures [G(T)CS] tended to continue. The most effective treatment for the MS/AS was ketogenic diet, followed by ACTH and ESM. At the last follow-up, 55 patients or 68 % of all the patients had remission of epilepsy, 11 patients or 14 % experienced a recurrence of GTCS after a long remission period but easily regained control, and the remaining 15 patients or 18 % continued to have seizures and intellectual outcomes were poor. In one half of these patients with poor outcomes, repeated minor epileptic status and nocturnal generalized tonic seizures persisted. A family history of epilepsy and a combination of minor epileptic status are risk factors for poor outcomes.

CONCLUSION

MAE is considered to form a clinical spectrum ranging in its main seizure type from myoclonic to atonic, and in seizure and intellectual outcomes from benign to malignant. The overall prognosis, despite initial resistance to treatment, appears to be much better than originally thought when ILAE definitions excluding SME are followed.

D-bifunctional protein deficiency with fetal ascites, polyhydramnios, and contractures of hands and toes

Fetal abnormalities including chylous ascites, polyhydramnios, claw hands, and hammer toes were identified in an infant who had a missense mutation R106P and a 52bp deletion in the gene for a peroxisomal beta-oxidation enzyme, D-3-hydroxyacyl-CoA dehydratase/D-3-hydroxyacyl-CoA dehydrogenase, D-bifunctional protein. The patient had psychomotor retardation and craniofacial dysmorphism and died at 7 months of age. The patient had atypical fetal manifestations of this enzyme deficiency.

Myoclonic-astatic epilepsy of early childhood--clinical and EEG analysis of myoclonic-astatic seizures, and discussions on the nosology of the syndrome

PURPOSE

The aim of this study is to elucidate the clinical and neurophysiological characteristics of the myoclonic, myoclonic-astatic, or astatic seizures in patients with myoclonic-astatic epilepsy (MAE) of early childhood, and to discuss on the nosology of this unique epileptic syndrome.

SUBJECTS

The subjects included 30 patients, who fulfilled the following modified International League Against Epilepsy (ILAE) criteria for MAE, and whose main seizures were captured by video-electroencephalographs (EEG) or polygraphs. The modified ILAE criteria includes: (1) normal development before onset of epilepsy and absence of organic cerebral abnormalities; (2) onset of myoclonic, myoclonic-astatic or astatic seizures between 7 months and 6 years of age; (3) presence of generalized spike- or polyspike-wave EEG discharges at 2-3 Hz, without focal spike discharges; and (4) exclusion of severe and benign myoclonic epilepsy (SME, BME) in infants and cryptogenic Lennox-Gastaut syndrome based on the ILAE definitions.

RESULTS

The seizures were investigated precisely by video-EEG (n=5), polygraph (n=2), and video-polygraph (n=23), which identified myoclonic seizures in 16 cases (myoclonic group), atonic seizures, with or without preceding minor myoclonus, in 11 cases (atonic group), and myoclonic-atonic seizures in three cases. All patients had a history of drop attacks, apart from ten patients with myoclonic seizures. Myoclonic seizures, involving mainly the axial muscles were classified into those with mild intensity not sufficient to cause the patients to fall (n=10) and those that are stronger and sufficient to cause astatic falling due to flexion of the waist or extension of the trunk (n=6). Patients in the atonic group fell straight downward, landed on their buttocks, and recovered immediately. Analysis of the ictal EEGs showed that all attacks corresponded to the generalized spike or polyspikes-and-wave complexes. In the atonic form, the spike-and-wave morphology was characterized by a positive-negative-deep-positive wave followed by a large negative slow wave. In two patients, the intensity of the atonia appeared to correspond to the depth of the positive component of the spike-and-wave complexes. We did not detect any significant differences in the clinical and EEG features and prognosis, between the atonic and myoclonic groups.

CONCLUSIONS

Although the determination of exact seizure type is a prerequisite for diagnosing an epileptic syndrome, the strict differentiation of seizure type into either a myoclonic or atonic form, does not appear to have a significant impact on the outcome or in delineating this unique epileptic syndrome. At present, we consider it better to follow the current International Classification of Epileptic Syndromes and Epilepsies until a more appropriate system than the clinico-electrical approach for classifying patients with MAE is available.

[Early phase II clinical trial of amrubicin hydrochloride in patients with malignant lymphoma]

An early phase II multi-center collaborative study of amrubicin hydrochloride, a novel synthetic anthracycline derivative anticancer agent, was conducted for malignant lymphoma at 12 institutions nationwide. A total of 41 patients were enrolled in this study between January 1988 and October 1990. Of these, 36 patients, six patients with Hodgkin's disease (HD) and 30 patients with non-Hodgkin's lymphoma (NHL), were eligible for the study. The starting dose of amrubicin hydrochloride was 100 mg/m2 (body surface area) and it was administered once every three weeks, in principle. The efficacy was assessed for 34 patients, excluding two patients: one who has not been followed up adequately and the other violated the dosing schedule (once per week). The overall response rates (CR + PR) were 50.0% (3/6) for HD and 42.9% (12/28) for NHL. Furthermore, a relatively high response rate was noted in 8 (36.4%) of 22 NHL patients who had been treated with other anthracycline derivatives prior to the trial. The safety of amrubicin hydrochloride was assessed for 36 eligible patients. Leukopenia (grade 3 or higher) and thrombocytopenia were noted in 21 patients (58.3%) and 10 patients (27.8%), respectively. Anorexia, nausea/vomiting, fever, alopecia, decrease in hemoglobin and elevations of GOT and GPT levels were observed with a relatively high frequency. Other than myelosuppression, the following adverse reactions (grade 3 or higher) occurred during the course of the trial: diarrhea (two patients), alopecia (two patients), stomatitis (one patient), anorexia (one patient), nausea/vomiting (one patient) and fever (one patient). In conclusion, these results indicate that amrubicin hydrochloride is effective in the treatment of patients with malignant lymphoma.

Study on photo-pattern sensitivity in patients with electronic screen game-induced seizures (ESGS): effects of spatial resolution, brightness, and pattern movement

PURPOSE

With the ever-increasing popularity of computers, electronic screen game-induced seizure (ESGS) is beginning to pose a serious social problem. To elucidate the pathophysiology of ESGS, with the ultimate goal of prevention, we have been studying photo-pattern sensitivity in detail with a pattern-stimulation test using a CRT (cathode ray tube) display. This method is referred to as the "CRT-pattern test."

METHODS

We studied 17 patients brought to our department for evaluation of ESGS. EEG responses were recorded during exposure to various patterns consisting of three elements: spatial resolution, brightness perception, and pattern-movement recognition displayed on a CRT monitor. Photo-paroxysmal response (PPR) frequencies were compiled for each stimulation.

RESULTS

PPR was induced by the CRT-pattern test in nine of the 17 cases. In four cases, PPR induction was obtained only after introducing CRT-pattern tests in addition to standard intermittent photic stimulation (IPS). The rate of PPR induction differed according to the type of pattern, spatial frequency, and pattern-reversal frequency. However, neither the clarity of the edges of a pattern nor changes in the brightness of a pattern element had any effect on the rate of PPR induction. With the exception of a few subjects, the stimulation caused by pattern movement was not effective in eliciting PPR. Six cases in whom spatial resolution was involved showed occipital dominance in PPR provocation, and three in whom brightness perception and pattern movement recognition was involved showed frontal dominance.

CONCLUSIONS

The CRT-pattern test is useful for identifying patients with photosensitivity among patients considered to have incidental or nonphotosensitive seizures unresponsive to standard IPS. Patients with ESGS caused by photosensitivity can be divided into two groups: those with occipital dominance for PPR provocation, in whom spatial resolution is involved; and another group with frontal dominance, in whom brightness perception and pattern-movement recognition (or possibly perception of colors) are involved.