高齢で発症し, 上肢の姿勢振戦あるいは頸部の振戦を有するが, 振戦以外の症状を呈さず, 原因疾患の明かでない「老人性振戦」について臨床・生理学的に検索し, その特徴を検討した.
60歳以上で発症し, 上肢の姿勢振戦を主徴とする男6例, 女10例, 計16例 (検査時平均年齢73.4歳) の患者の上腕二頭筋, 上腕三頭筋, 前腕屈筋群, 前腕伸筋群の表面筋電図を記録し, 振戦の周波数を測定するとともに拮抗筋同士が交代性に活動しているか否かについて調べた. 一部の例では手関節を機械的に急速に背屈または掌屈させ, 振戦の周期の変化をみた. 同様の検査を臨床的にと診断された, 発症年齢60歳末満の男15例, 女7例, 計22例 (検査時平均年齢54.1歳) でも行い対照とした.
振戦の周波数は老人性振戦で6.2±1.3Hz (平均±SD), 対照群で7.3±1.5Hzと, 前者で低かったが, 対照群でも検査時に60歳以上の患者では6.0±0.8Hzと低く, 周波数は検査時年齢と負の相関を示し, 発症年齢との関連はなかった. 拮抗筋同士の筋放電は, 老人性振戦では15例で相反性を示した. 対照群のうち7例では拮抗筋同士が同期して活動していたが, 検査時に高齢の患者では相反性放電を示す例が多かった. 手関節に機械的刺激を与え, 筋に伸張を加えた例では全例で, 振戦の周期が re-set された.
以上より老人性振戦は周波数が低く, 拮抗筋同士が相反性放電を示す例が多いが, 若年発症でも検査時に高齢の患者では同様の態度をとり, こういった現象は発症年齢よりも検査時年齢に依存し, の一般的な特徴と考えられた. この結果は老人性振戦がの一型であるとする考えを支持していた.

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振戦は安静時振戦,姿勢時振戦,企図振戦,動作時振戦に区別される.小脳性協調運動障害の現れと解される動作時振戦や代謝異常による振戦を除いて,小脳歯状核・赤核・視床を結ぶ経路のどこかの障害で振戦のリズムが発生し,振戦の性状の違いは筋トーヌスの差によるとの説がある.パーキンソン病の振戦とに対する薬物治療以外は特異的な内服療法はなく,視床Vim核の定位的破壊術の適用が考慮される症例がある.

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The vibration called tremor is widely seen in human beings. In the medical field, the many diseases display tremor which is typically represented by Parkinson's disease and essential tremor. The number of patients with Parkinson's disease is about 100,000 in Japan and will increase in the future. Parkinson's disease has three typical signs, namely tremor, rigidity, and hypokinesia. Tremor is the most dominant symptom in the triad. It is difficult to discriminate Parkinson's disease from several other diseases simulating Parkinson's symptoms. Medical treatment is often effective in Parkinson's disease, but in general these are transitory. In this study, we tried to discriminate these diseases by measuring tremor using accelerometers. We developed a measuring and analyzing system for tremor in the upper limbs using accelerometers, which were put on both hands. The posture of the subjects during measuring their tremor was as follows: Subjects sat on a chair and put their elbows on a desk. We placed their forearms at an angle of 45°from the horizontal plane. Tremor signals were analyzed and the dominant frequency was calculated as "main frequency". The severity of the tremor can be quantified by the spectra. We adopted the main frequency and its tremor strength as two tremor indicators. The measuring system was applied to 42 patients with Parkinson's disease (mean age, 73.8 years), 5 patients with drug-induced Parkinsonism (mean age, 72.6 years) and 36 patients with essential tremor (mean age, 67.8 years). The system could significantly discriminate the drug-induced Parkinsonian tremor from the other two types of tremor diseases (p<0.01). The degree of tremor could be quantified using an engineering index, namely, the power of the main frequency. We studied the relationship between age and the symptoms of the Parkinson's disease and essential tremor. The results were as follows: In Parkinson's disease the frequency decreased with increasing length of tremor history. In essential tremor, the main frequency decreased and the power of the frequency increased with the age of the patients. We tried to control tremor using the biofeedback technique in three healthy subjects. An effect on tremor frequency was observed during the biofeedback training. The power of high-frequencies tremors (which we defined as tremors at frequency between 5 and 15 [Hz]) increased in all patients. We assume it possible to control the patients' tremors using the biofeedback technique. Biofeedback is considered to be a useful therapy for all patients with tremor, because it is not invasive and it doesn't require any medicines such as L-Dopa.

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Primidone in a dosage of 100 to 1000 mg with a mean of 400 mg was orally administered to 13 patients with essential tremor, whose age ranged from 44 to 88 with a mean of 64. Clinical evaluation was based on tremor score, hand writing, and of daily life activities. Serum drug levels of primidone, phenobarbital, and phenylethylmalonamide were measured in some patients in contrast to the clinical assessments. The results obtained were as follows.
1. Primidone was effective in 10 out of 13 patients (76.9%).
2. Dose-related benefits were present under the daily dosage of 400 mg, and the initial dose of 100 mg with gradual increase of 50-100 mg each at 3-to 4-day intervals considered to be appropriate.
3. Neither primidone, phenobarbital, nor phenylethylmalonamide showed close correlation between serum concentration and effectiveness for tremor.
4. Side-effects such as dizziness, sleepiness, and nausea were occasionally encountered, which, however, were preventable by starting primidone from a low dose as mentioned above.

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鏡像書字 (mirror writing) の出現機構, 責任部位は現在のところ不明であるが, 患者やパーキンソン病患者で高頻度にみられることから, 視床との関連を示唆する報告がある.今回, 脳卒中患者において, 視床と他の病変部での鏡像書字の出現率を調査し, 健常人および他の神経疾患患者での出現率と比較・検討した.対象は脳卒中31名 (視床10名, その他21名) , パーキンソン病34名, 18名, 健常人84名で計167名である.Mini-Mental Stateテストを施行し, 痴呆患者は除外した.それぞれ右手および左手で名前, 数字, アルファベット, 時計の図等を書かせた.書かれた文字の50%以上が鏡像パターンの場合を陽性とした.鏡像書字は, 脳卒中12.9% (視床10%, その他14.3%) , パーキンソン病26.5%, 33.3%, 健常人8.3%にみられた.パーキンソン病患者, 患者で頻度が高いことは過去の報告とほぼ一致したが, 脳卒中患者では視床と他の病変部位で, 鏡像書字の出現率に明らかな差を認めなかった.

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人の前腕の振戦加速度データに対するAR (autoregressive)モデルの適用が,パーキンソン病と類縁疾患との鑑別診断に有効であるかどうかを検討した.ARモデルの次数は,赤池に従って, FPE (final prediction error)を最小にする7に設定した.対象とした被験者は,パーキンソン病患者18名,患者20名,およびコントロールとして健常高齢者13名である.その結果,振戦疾患患者と健常高齢者の振戦については,実軸上に存在する特性根の符号,及び利き腕の振戦の基本共振周波数における周波数帯域幅に高度な有意差があり,パーキンソン病患者と患者の振戦については,利き腕の振戦の基本共振周波数における周波数帯域幅の分散に有意差があったので報告する.

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Voice tremor has been associated with neurological disorders such as essential tremor, Parkinson's disease, cerebellar ataxia. Voice tremor most commonly accompanies essen- tial tremor which is a common neurologic disorder that is often an autosomal dominant trait. It may appear in childhood or later life and runs a slowly progressive course.
Voice tremor is characterized by rhythmic alternations in pitch and loudness of vowel sounds, and is usually accompanied by tremor in other parts of the body. The frequency ranges from 4 to 8 Hz. Physiological lesions or mechanisms of voice tremor have not been throughly studied. Essential voice tremor can resemble spasmodic dysphonia, therefore differentiation between essential voice tremor and spasmodic dysphonia must be made. Laryngoscopy and laryngeal electromyography are useful for diagnosis.
Currently available therapies for voice tremor are not satisfactory, however propranolol is most commonly used.

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脳深部刺激療法 (DBS) は薬剤抵抗性の本態性 振戦に対する外科治療として確立している．その優れた 振戦抑制効果について多数の報告があるが，疾患の進行 に伴いより高い刺激強度が必要となり，それによる副作 用を生じる症例も存在する．今回，従来の DBS デバイ スでは振戦の制御が困難であった症例に対し，新規デバ イスの交換により良好な治療効果が得られた一例を経験 したため報告する．

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パーキンソン病患者や患者が振戦抑制のための訓練にバイオフィードバツクによる方法を用いる場合に, どのような生体情報をフィードバックすればよいかについて研究した.健常者の生理的振戦と病理的振戦との差の情報をフィードバックすればよいという観点に立って, 前腕振戦のより全体的な特徴をとらえるために, 前腕振戦へのAR (自己回帰)モデルの適用を試みた。被験者は18人のパーキンソン病患者, 20人の患者, コントロール被験者として13人の健常高齢者である.著者らはFPE(final prediction error)を最小にする7次のARモデルを用いた.そして, (1)パーキンソン病患者や患者にみられる病理的振戦から得られる特性方程式は負の実根を因子として含むことが多い(逆に, 健常者の生理的な振戦から得られる特性方程式は正の実根を因子として含むことが多い), (2)患者の病理的振戦から得られる特性方程式の基本周波数を表す特性根の絶対値は1に近いことが多い(逆に, 健常者の生理的な振戦から得られる特性方程式の基本周波数を表す特性根の絶対値は1から遠いことが多い)という結果を得た.病理的振戦の患者には, ここで得られた相違点をフィードバック情報として提示し, 訓練を行う予定である.本研究で得られた結果は, パーキンソン病や, の診断支援に応用可能であると考えられる.

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症例は70歳,女性. 20歳頃より両手指の姿勢時振戦を認め,悪化傾向なく経過していた. 65歳より近医でパーキンソン病としてL-DOPAを投与されていたが,振戦以外の症状は認められず, 1999年にL-DOPA中止後も症状の増悪は認められなかったため,と診断された. 2000年2月よりファモチジンの内服を開始したところ, 3月頃よりパーキンソン症状が出現した.ファモチジンが薬剤性パーキンソニズムの原因になり得るかどうか,今後の臨床的観察が必要と考え,症例を報告した.

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Involuntary movements, a collective term for movements occurring without volition, are the hallmark of hyperkinetic movement disorders. The main types of hyperkinetic movement disorders comprise restless leg syndrome, tremor, chorea, dystonia, myoclonus, and tics, along with other symptoms including akathisia, hemifacial spasm, myokymia, stereotypies, periodic limb movement disorder, hyperekplexia, and alien hand syndrome. Variations in movement symptoms termed dyskinesia are often observed in clinical practice in response to levodopa and dopamine agonist treatment. Despite falling outside the narrow definition of involuntary movements, psychogenic involuntary movements that can be temporarily voluntarily suppressed and involuntary movements caused by adverse drug effects also require attention. Most involuntary movements can be diagnosed through observation of clinical characteristics. However, it is important to begin by accurately noting the observed movements without trying to fit them into an existing diagnostic category. The initial focus of observation should be temporal patterns of occurrence, specifically whether movements are irregular or have a constant or periodically recurrent rhythm. Tremors are characterized by constant rhythmic oscillations in contrast with the irregular pattern presented by other types of involuntary movement. In cases where it is difficult to differentiate between tremors and other movement disorders, skin palpation and surface electromyography are useful for diagnosis. The choice of drug therapy among the many available types should be based on the pathophysiology of the hyperkinetic (involuntary) movements or underlying disorder.

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This paper discusses whether an application of the AR model to an acceleration data of a tremor is useful for a differential diagnosis between Parkinson's disease and other diseases with tremors, such as the essential tremor. The degree of the AR model was chosen as 7 according to Akaike's FPE criterion. The examinees were 19 Parkinson's disease patients, 21 essential tremor patients —a disease that mainly appears in the elderly and in Parkinson's disease patients— and 13 healthy elderly as the control. This study on the acceleration data showed that the first prediction coefficient, the same as the main tremor frequency, is the parameter that classifies the Parkinson's disease group and the essential tremor group. The 7th prediction coefficient is the parameter that classifies the pathological tremors observed in Parkinson's disease and essential tremor disease patients and the physiological tremors observed in healthy subjects. Although the effects of another prediction coefficients on the differential diagnosis between Parkinson's disease and other diseases with tremors are not clarified during this stage, adding the AR model parameters to diagnostics by the main tremor frequency can increase reliability of the diagnostics. This paper showed the usefulness of the AR model for the acceleration data of the tremor to classify Parkinson's disease and other diseases with tremors.

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Patients with voice tremor present with shaking voice which has a frequency of 4-5 Hz in their vocal tract. In most of cases, voice tremor is refractory to conservative treatment such as medication or voice therapy and the symptoms may affect a patient’s quality of life. We experienced a case of voice tremor accompanied by essential tremor of the upper extremities who was treated with bilateral thalamic deep brain stimulation (DBS). The results of an acoustic analysis and laryngeal endoscopic findings showed a partial improvement following unilateral DBS and complete improvement following bilateral DBS. FTRI, Fatr, ATRI, Jitter, Shimmer, vF0, vAm, NHR, sPPQ and sAPQ seemed to be useful parameters of voice tremor. The results suggest that the indication of DBS should be discussed for patients severely affected by voice tremor after considering the patient’s age, accompanying symptoms, backgrounds, occupation and needs.

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There are many kind of involuntary action. Especially, the authors focus on the essential tremor. The incidence of essential tremor is high and it has a bad effect for activity of daily life. However, approach to treating essential tremor is symptomatic therapy because the pathogenesis is not clear. We developed an equipment for patients of essential tremor to support activity of daily living. The equipment targets the wrist because essential tremor develops most frequently in the wrist. The equipment has bag structure made by plastic film and it expands by air pressure. So, the equipment is lightweight, compact and wearable by using air pressure.

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Essential tremor (ET) is most frequent movement disorder in individuals above 40 years old. The prevalence of ET increases steeply with increasing ages. ET is slowly progressive disorder which is sometimes causing severe disability but is not life–limiting.

Diagnosis of ET is based on clinical examination and neurological history, as a specific biological marker or diagnostic test is not available. Differences among tremor disorders are important in published clinical criteria for ET. In pharmacotherapy, Propranolol and Primidone have level A recommendations. And Topiramate and Gabapentin have level B recommendations. However, drugs for ET is not enough reduction of tremor and side–effects is common. Botulinum toxin is possibly effective. Vim thalamotomy is highly effective but side–effects of surgery should be considered. Noninvasive functional neurosurgery using transcranial MRI guided focus ultrasound is a novel treatment and will become a new option near future.

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薬剤抵抗性の

（essential tremor：ET）10例（男性8例，女性2例，67.1±17.5歳，全例右利き）に対してMRガイド下集束超音波（MR–guided focused ultrasound：MRgFUS）による左視床中間腹側核（ventral intermediate nucleus：Vim）破壊術を行い，12か月後までの有効性と安全性を検討した．治療直後から全例で右上肢の振戦が改善し，2例で振戦が再増悪したものの，右上肢のClinical Rating Scale for Tremorの平均値は12か月後まで約60%の低下が持続した．しかし，Quality of Life in Essential Tremor QuestionnaireのGlobal Impression Scoreの平均値は有意な改善を認めなかった．有害事象の大部分は軽微かつ一過性であり，治療から6か月後以降に新規の有害事象は生じなかった．MRgFUSによる片側Vim破壊術は薬剤抵抗性のETに対する治療選択肢の1つであるが，振戦の改善効果を高めるとともに，より多数例を長期に検討する必要がある．

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The objective of this paper is to develop a signal processing method to extract voluntary movement from EMG signal of patients with essential tremor We have been developing an EMG-controlled exoskeletal robot to support the daily living activity of the patients and this processing method is needed to control the robot accurately with the user's intention EMG signal of the patients is the mixture of voluntary movement signal and involuntary tremor signal Therefore, to control the robot accurately, only voluntary movement signal must be extracted from EMG signal To date, we have been developing a filter to remove tremor signal from EMG signal This filter had large effect on removing tremor signal, however, this filter had problem in removing also voluntary movement signal In this paper, we proposed a method which is able to remove only tremor signal selectively We use a frequency of tremor signal in EMG as an indicator to switch on/off use of previously proposed tremor removing filter The frequency is likely to be changed depending on the patient's state of movement, so, we set a threshold to the frequency through an analysis Finally, we input a signal which is processed with proposed method to neural network and evaluate the recognition accuracy The proposed method succeeded in improving accuracy compared with the previous method However, further research is needed to improve the recognition more by reviewing a condition to switching on/off use of tremor removing filter

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Essential tremor is a disorder that causes involuntary oscillations in patients while engaging in actions or while maintaining a posture. The patients have serious difficulties in performing activities of daily living such as eating food, drinking water, and writing. We have thus been developing an EMG-controlled exoskeleton to suppress tremors. In this paper, the extent of tremor suppression by using the proposed exoskeleton is reported. Thought an experiment, it confirmed that the amplitude of tremor while wearing the exoskeleton was 50〜70% smaller than that of no support case. This result indicated that an approach to use exoskeleton is effective way to suppress tremor. Toward the practical use, the fitting of the robot must be improved. As a future work, to make it possible to fit the robot automatically, we will define the effective point to suppress tremor originated from the particular point of the body.

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