脳インプラント、まひ患者の上肢で初の臨床試験

【ワシントンＡＦＰ＝時事】人工知能（ＡＩ）を使って思考を読み取り、神経系を通じて電気信号を送ってまひした上肢の動きを回復させる新技術が、スイスで初めて試験段階に入っている。（写真は神経刺激装置〈ＩＰＧ〉への電極挿入の様子。オランダの医療技術企業オンワード・メディカル提供）
　今年５月には、脊椎インプラントとブレーン・コンピューター・インターフェース（ＢＣＩ）を組み合わせ、下半身不随の患者の歩行を回復させた画期的な研究結果が科学誌「ネイチャー」に発表された。
　だが、開発に携わるオランダの医療技術企業オンワード・メディカルによると腕や手、指など「上肢の機能」に使用されるのは今回が初めてとなる。
　同社の共同設立者で、インプラントの埋め込み手術を担当した外科医のジョセリーヌ・ブロッホ氏は、歩行にはバランスの問題などがあるが、「腕の可動性は（足よりも）もっと複雑だ」とＡＦＰに語った。「手の筋肉組織は非常に細かく、動作する際には多くの小さな筋肉が同時に動いている」と説明する。
　匿名の患者は、転倒によって腕が不自由になった４６歳のスイス人男性。先月、スイス・ローザンヌ大学病院で２回の手術が行われた。
　最初の手術では頭蓋を小さな範囲で切除し、フランス原子力庁などが運営する研究機関クリナテックが開発した直径数センチの脳インプラントを挿入。
　次の手術でオンワードが開発したクレジットカード大の電気装置を患者の腹部に埋め込み、電極を介してそれを脊柱上部に接続した。
　ＢＣＩはＡＩを用いて脳の電気信号から患者の意思を解読し、脊髄刺激装置に指示を送る「デジタルブリッジ」として機能する。
　患者はまだ訓練段階だが、ブロッホ氏は「今のところ順調だ。脳の活動記録を見ると、刺激も機能している」と述べた。
　今後、脳インプラントにさまざまな動きを認識させる必要があり、自然な動きを実現するには数か月かかるという。この臨床試験にはさらに２人の患者の参加が見込まれている。
　脳インプラントは長年、ＳＦの世界にしかない想像の技術だったが、実業家のイーロン・マスク氏が立ち上げた新興企業「ニューラリンク」などによって現在、急成長中の分野となっている。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2023/09/28-16:50）

A paralyzed Swiss man has become the first person to test a new technology that reads his thoughts using AI and then transmits signals through his own nervous system to his arms, hands and fingers in order to restore movement.
The treatment, a combination of a brain-computer interface and a spinal implant, had previously allow a paraplegic patient to walk again, a breakthrough that was published in the scientific journal Nature in May.
But this is the first time it's being used for upper extremity function, Onward, the Dutch company behind it, said Wednesday.
The mobility of the arm is more complex, surgeon Jocelyne Bloch, who carried out the implantation procedures, told AFP.
Though walking comes with its own challenges -- notably balance -- the musculature of the hand is quite fine, with many different small muscles activated at the same time for certain movements, she said.
The patient, who wishes to remain anonymous, is a 46-year-old who lost the use of his arms after a fall. Two operations were carried out last month at the Lausanne University Hospital in Switzerland.
The first involved removing a small piece of cranial bone and inserting in its place the brain implant, which was developed by the French group CEA-Clinatec and measures a few centimeters in diameter.
In the second, surgeons placed a stimulator roughly the size of a credit card developed by Onward inside the patient's abdomen, and connected it through electrodes to the top of his spinal column.
The brain-computer interface (BCI) records brain signals and decodes them using artificial intelligence to make sense of the patient's intentions, acting as a digital bridge to send these instructions on to the spinal cord stimulator.
It's going well so far, said Bloch, who co-founded Onward and is a consultant for the company. We are able to record brain activity, and we know that the stimulation works, she said.
But it is too early to talk about what progress he has made.
- Still in training -
The patient is still in the training phase, teaching his brain implant to recognize the different desired movements.
The movements will then have to be practiced many times before they can become natural. The process will take a few months, according to Dr. Bloch.
Two more patients are scheduled to participate in this clinical trial, and the full results will be published later.
Spinal cord stimulation has already been used in the past to successfully move paralyzed patients' arms, but without reading their thoughts by pairing it with a brain implant.
And brain implants have already been used so that a patient can control an exoskeleton. The Battelle research organization used a brain implant to restore movement in a patient's arm -- through a sleeve of electrodes placed on the forearm, stimulating the muscles required from above.
Onward is unique in our focus on restoring movement in people who have paralysis by stimulating the spinal cord, the company's CEO Dave Marver told AFP, adding the technology could be commercialized by the end of the decade.
Brain implants were long trapped in the realm of science fiction, but the field is now rapidly growing thanks to firms like Synchron and Elon Musk's Neuralink.
They are working on having paralyzed patients to control computers through thought, restoring for example the ability to write.