Comparison of Visual Evoked Potential Components between Laser and Cathod-Ray Tubes Stimulation in Healthy Human Subjects

We studied the differences in latency and amplitude between the laser stimulated visual evoked potentials (VEPs) and the cathode-ray tubes (CRTs) stimulated VEPs to estimate the risk of inducing photosensitive epilepsy by laser displays. Twenty healthy subjects were recruited for the study. Red and blue light stimulations were flashed in 1, 7.5 and 15Hz. The latency of P1, N1, P2 and N2 in 1 Hz stimulation revealed no significant difference by a paired t test between laser and CRT stimulation. The peak-to-peak amplitude was significantly smaller with red or blue laser stimulation than with red or blue CRT stimulation, for PI-N1 and N1-P2 at 7.5Hz stimulation, and for N1-P2 and P2-N2 at 15Hz stimulation. We therefore postulate that laser does not produce more excitability to occipital cerebral cortex than CRT does. There was no evidence to say that laser stimulation is more dangerous as the risk of inducing photosensitive epilepsy than conventional CRT stimulation

富士川流域におけるCreutzfeldt-Jakob病の疫学的検討

1970年代以降,静岡,山梨両県の富士川流域にCreutzfeldt-Jakob病(CJD)が多いことは知られていたが,筆者らは同地域に位置する共立蒲原総合病院で1999年の1年間に3例のCJD患者を経験したことから,静岡,山梨両県の36施設に対し,1990年から1999年の10年間にわたるCJD患者についてのアンケート調査を行なった.36施設中26施設から文献例を含む合計34例のCJD患者が確認された.症例は男性16例,女性18例で,平均発症年齢は62.5±10.7歳であった.遺伝子変異が10/34例(29.4%)にみられ,全例がcodon 200の変異(CJD^)であり,そのうち2家系に家族内発症を認めた.臨床所見では高率にミオクローヌス(95.7%)と脳波上の周期性同期性放電(periodic synchronous discharge,PSD)(95.7%)を認め,従来の孤発例やCJD^の特徴と一致していた.過去10年間では富士川中流地区に,1999年の1年間では下流地区に,それぞれCJD患者の有為な集積が確認された(ボアソン分析でpの10例のうち8例が富士川流域(7例が中流～下流地区)の出身であったことから,同地区がCJD^の主たる集積地区と考えられた.また周辺の静岡市から三島市にかけても症例(CJD^2例を含む)が散見され,同地区まで含めた範囲をCJD関連地域として注目すべきと考えた.An epidemiological study of Creutzfeldt-Jakob disease (CJD) was carried out during the period between 1990 and 1999. A total of 34 cases with CJD was collected from the information provided by neurologists, psychiatrists, and neurosurgeons in Shizuoka and Yamanashi Prefecture. There was no significant difference between males and females. The average age of onset was 62.5 years, with high occurrence seen in patients in their fifties, sixties, and seventies. The mean duration of CJD was 7.3 months. There were no cases with a cadaveric dural graft. There were two families with CJD patients having codon 200 mutations. Myoclonus occurred in 95.7% of cases and there were electroencephalographic (EEG) tracings with periodic synchronous discharges (PSD) in 95.7% of the cases. Ten patients had a mutation at codon 200 of prion protein gene (CJD^) . In the middle reaches of the Fuji River basin (Yamanashi Prefecture), the retrospective incidence of CJD between 1990 and 1999 was 5.77 cases/million/annum; highly significant clustering (p = 0.01) was confirmed in this area. The point prevalence rate in 1999 at the lower reaches of the Fuji River (eastern part of Shizuoka Prefecture) was 9.78 cases/million/annum. These results demonstrated significant clusters of CJD patients at the middle and lower reaches of the Fuji River. The incidence of CJD^ appeared to be much higher in these areas than other areas in Japan

ミトコンドリア脳筋症における少量ジクロロ酢酸療法の臨床的評価 : ジクロロ酢酸少量内服療法が卒中様発作抑制に有効であった5症例について

筋生検・ミトコンドリアDNA遺伝子診断などによりMELASと診断され,脳卒中様発作を繰り返し,頭部MRIで病変が確認された成人MELAS5症例に,少量のジクロロ酢酸を含むLiverall^を投与し,脳卒中様発作を抑制できるか臨床経過を検討した.内服開始後は,全例で頭部MRI画像上病変を認める脳卒中様発作は生じなかった.従来小児科領域で報告されていた必要量よりも少量で発作を抑制できる可能性があると考えられた.しかし,血清中の乳酸・ピルビン酸は異常値を示す場合もあり,痙攣発作やイレウスなどの合併症状を呈する症例も2例あり,今後の検討が必要と考えられた.本論文の要旨は,第44回日本神経学会総会(横浜,2003年5月)において発表した.In five adult patients with MELAS, we evaluated clinical symptoms, FLAIR and DWI brain MRI, and serum level of lactate and pyruvic acid, to assess whether stroke-like episodes in MELAS are suppressed by small dose of dichloroacetate. After beginning oral therapy of Liverall^ for MELAS, none of the five cases showed any occurrence of the stroke-like episodes associated with brain MRI lesions. We noticed that the stroke-like episodes were suppressed by using a smaller dose of dichloroacetate, compared with the dose required for therapy of pediatric patients with MELAS. In spite of favorable effect of Liverall^ for MELAS in symptomatic and MRI evaluations, the serum level of lactate and pyruvic acid continued to show abnormal values and convulsive seizures or ileus occurred in a few cases. Further investigations are required to know whether Liverall^ is a useful therapeutic drug

筋萎縮性側索硬化症における筋核磁気共鳴画像(MRI)の検討

筋萎縮性側索硬化症(amyotrophic lateral sclerosis;ALS)の診断は,厚生労働省の診断基準に基づいて臨床症候,電気生理学的所見,病理学的所見などを基に総合的に判定して得られる.近年では,頭部核磁気共鳴画像(magnetic resonance imaging;MRI)上,内包後脚を中心として錐体路に一致して出現するT2高信号域が異常所見として報告されている.一方,筋MRIにおける筋内信号強度の上昇は,炎症および浮腫性変化を反映していると考えられている.非典型的なALSでは臨床症候と検査所見からだけでは他の疾患との鑑別が困難なこともあるため,今回我々は,ALS患者の下腿筋MRIについて検討した.対象は,ALS患者10例で男性7例,女性3例からなり,平均年齢は,68.6±11.2歳(49～87歳)である.発病初期より球症状が顕著な症例が1例,筋力低下が上肢に強い症例が3例,下肢に強い症例が6例あった.9例に下腿筋MRI,10例に針筋電図と末梢神経伝導検査を施行した.発病初期の筋力低下が下肢に強い6例の筋MRI・T2強調画像において筋内信号強度の上昇を認めた.それに対して筋力低下が上肢に強い症例や球症状の顕著な症例では,筋MRIの筋内信号強度は正常であった.また,筋内信号が上昇していた6例のうち5例における腓骨神経電気刺激で,複合筋活動電位の著明な振幅低下を認めた.ALS患者における筋MRI・T2強調画像の信号強度上昇は,脱神経後の浮腫性変化を反映していると考えられるため,ALS患者の病期判定や他疾患との鑑別が困難な場合の補助検査のひとつとして筋MRIは有用である.Various objective measurements can be used to diagnose amyotrophic lateral sclerosis (ALS). T2-weighted brain MRI images revealed high signal areas at the posterior limb of the internal capsules in ALS patients. Recently, muscle MRI proved useful to evaluate abnormalities of the muscle in myositis patients. Therefore, in the present study, we examined muscle MRI of leg muscles in ALS patients, and correlated MRI with functional measurements, such as muscle strength, and compound muscle action potential amplitude of the tibialis anterior (TA) after stimulation of the peroneal nerve. The subjects consisted of 10 ALS patients (7 males and 3 females), ranging in age from 49 to 87. Neurologic symptoms at the onset of ALS consisted of bulbar dysfunction in one patient, upper extremity involvement in three patients, and lower extremity involvement in six patients. Muscle MRI of the legs was performed in 9 (ALS patients. A peripheral nerve conduction study was performed on the peroneal nerve, with the recording electrode over the TA. The T2-weighted muscle MRI images revealed high signal aeras in the muscle in six ALS patients, whose muscle weakness existed predominantly in the lower extremities. Extracellular fluid accumulation has been proposed to be responsible for the signal increase of denervated muscles on T2-weighted muscle MRI images. We assume that muscle MRI is useful to demonstrate the distribution of muscle involvement in ALS patients and to assess the disease\u27s stage

パーキンソン病及びパーキンソン症候群におけるすくみ足症例の画像的特徴

すくみ足は,歩行障害の一種で,パーキンソン病及びパーキンソン症候群に認められる症候の一つであるが,他のパーキンソン症候と異なる性質と病態で出現すると推測されている.そこで,外来受診中のすくみ足を伴う症例の画像所見を解析し,その責任病巣について検討した.その結果,すくみ足症例に高率に前頭葉病変が認められ,今まで報告のある前頭葉由来の仮説が裏付けられた.このことから,すくみ足治療は,前頭葉機能に注目して行うことが有用であると考えられた.Although it is known that frozen gait is a symptom of Parkinson\u27s disease (PA), it has not been fully studied in a variety of other diseases with parkinsonian syndrome, such as vascular parkinsonism, normal pressure hydrocephalus (NPH), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and multiple system atrophy. The present study was conducted to investigate whether common abnomalies of brain CT or MRI exist in patients with frozen gait. The subjects were of 7 patients with PA, 9 patients with stroke, 5 patients with both PA and stroke, 2 CBD patients, 1 PSP patient, and 1 NPH patient. Frontal white matter lesions were observed in 13 (93%) of 14 patients with PA or PA and stroke. Frontal lobe atrophy was observed in 5 (70%) of 7 patients with PA. Dysartheic disorders were associated in 6 (24%) of 25 patients with frozen gait. Since it is thought that frozen gait is a motor symptom related to frontal lobe dysfunction, the treatment of frozen gait might be conducted by improving frontal lobe function