Neuroprosthetic control and tetraplegia – Authors'reply
2013; Elsevier BV; Volume: 381; Issue: 9881 Linguagem: Inglês
10.1016/s0140-6736(13)61154-x
ISSN1474-547X
AutoresMichael L. Boninger, Galen W. Mitchell, Elizabeth C. Tyler‐Kabara, Jennifer L. Collinger, Andrew B. Schwartz,
Tópico(s)Muscle activation and electromyography studies
ResumoJon Stone and William Landau's main concern is the possibility that the patient's disorder might be functional (psychogenic) tetraplegia. We welcome the opportunity to present details of the patient's diagnosis, which were not included in our report1Collinger JL Wodlinger B Downey JE et al.High-performance neuroprosthetic control by an individual with tetraplegia.Lancet. 2013; 381: 557-564Summary Full Text Full Text PDF PubMed Scopus (1042) Google Scholar due to space limitations. The patient was thoroughly evaluated before enrolment, including a case review with her treating neurologist (GM) of more than 14 years. The patient first noted stiffness in her legs at age 36 years, 17 years before enrolment. Over several months, stiffness progressed to fatigue, weakness in the legs, and then to weakness in the arms over the following year. 3 years after symptom onset, the patient was too weak to walk and used a wheelchair full time; she had also developed subtle sensory symptoms and urinary retention. Upon presentation at the University of Pittsburgh, 4 years after symptom onset, pertinent examination findings were left lateral gaze-evoked jerk nystagmus, mild left arm weakness, and severe right arm weakness. In the leg, there was complete paralysis except for knee flexion, which was near normal, and hip flexion, which showed severe weakness. She had increased tone in the legs with bilateral plantar reflexes present. She had mild to moderate vibratory sense loss to the knees, without pinprick loss. There were no cerebellar signs in the arm that moved and no obvious truncal ataxia for a patient who could not stand. She had no history of depression or significant pain. She progressed with primarily motor dysfunction and became tetraplegic. Testing, at that time, failed to reveal a genetic disorder. After thorough evaluation for central and peripheral nervous system diseases, resulting in an unknown aetiology, it was determined she had a degenerative disorder diagnosed as spinal cerebellar syndrome. Her father had a very similar set of symptoms, with the addition of ataxia, and more recently, two of her siblings were diagnosed with multiple sclerosis. At the time of enrolment in the study,1Collinger JL Wodlinger B Downey JE et al.High-performance neuroprosthetic control by an individual with tetraplegia.Lancet. 2013; 381: 557-564Summary Full Text Full Text PDF PubMed Scopus (1042) Google Scholar she had 0/5 motor strength in all extremities, preserved—although subjectively slightly diminished— sensation, and decreased tone. With these additional details of our patient's history and symptoms, it should be clear that her condition is not consistent with functional psychogenic tetraplegia.2Stone J Warlow C Sharpe M The symptom of functional weakness: a controlled study of 107 patients.Brain. 2010; 133: 1537-1551Crossref PubMed Scopus (170) Google Scholar ABS has a patent application pending in the USA that covers some of the methods used in the study. The other authors declare that they have no conflicts of interest. Neuroprosthetic control and tetraplegiaThe neuroprosthetic achievements reported by Jennifer Collinger and colleagues (Feb 16, p 557)1 are remarkable. The diagnosis of the tetraplegic patient of the study is, however, puzzling. The patient has spinocerebellar ataxia without cerebellar features. Material available elsewhere2,3 suggests that her symptoms began rather suddenly 13 years before taking part in the study. She describes relapsing weakness, has normal looking hands, and, head rest excepted, no symptoms above the neck. This is unusual for spinocerebellar ataxia, which typically has slow onset with gradual deterioration. Full-Text PDF High-performance neuroprosthetic control by an individual with tetraplegiaWith continued development of neuroprosthetic limbs, individuals with long-term paralysis could recover the natural and intuitive command signals for hand placement, orientation, and reaching, allowing them to perform activities of daily living. Full-Text PDF
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