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BRIEF COMMUNICATIONS: J. Costa, R. Henriques, C. Barroso, J. Ferreira, A. Atalaia, and M. de Carvalho Upper limb tremor induced by peripheral nerve injury Neurology 2006; 67: 1884-1886 [Abstract] [Full text] [PDF]

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Upper limb tremor induced by peripheral nerve injury

Masharip Atadzhanov, Peter Mwaba   (27 June 2007)

Reply from the authors

Mamede de Carvalho, Joćo Costa, Joaquim Ferreira   (27 June 2007)

Upper limb tremor induced by peripheral nerve injury

William J. Weiner, Stephen G. Reich, MD   (12 March 2007)

Reply from the Authors

Mamede de Carvalho, Joćo Costa, Joaquim Ferreira   (12 March 2007)

Upper limb tremor induced by peripheral nerve injury 27 June 2007
Masharip Atadzhanov, University of Zambia Lusaka, Zambia, Peter Mwaba Send Correspondence to journal: Re: Upper limb tremor induced by peripheral nerve injury masharip{at}yahoo.com Masharip Atadzhanov, et al.	Costa et al continue the debate concerning whether "peripherally induced" movement disorders exist or whether they are psychogenic in origin. [1] We report a similar case. A 30-year old right-handed security guard was assaulted and sent to the casualty wing of the University Teaching Hospital with a dislocated right shoulder. The shoulder was reduced but 6 weeks later the patient developed mild tremor of the right hand. By the eighth week, tremor had progressed and became persistent. The patient was unable to use his right hand for daily activities including eating, drinking and writing. Past medical history was unremarkable and there were no family members with symptoms of movement disorders. Neurological examination revealed only persistent, rhythmic, jerky tremor of the right hand. The tremor presented at rest and worsened with voluntary movements. The hand tremor was associated with a postural component which had some characteristics of an overt cervical dystonia. All laboratory data, including liver function test, were normal. Slit lamp examination did not reveal Kayser-Fleischer rings. CT of the brain and EEG were unremarkable. Numerous medications were tried with no benefit. On examination at 1 year, there was no change in the character of the tremor and no other parkinsonian features other than some dystonic posture of the neck. We considered dystonic tremor but the patient did not meet all the clinical criteria. This is an unusual case of an indigenous African adult patient with dystonic tremor following peripheral trauma. Peripheral trauma has been associated with the subsequent development of primary dystonia [2,3], focal myoclonus, and tics. The role of peripheral trauma in the genesis of movement disorders has not been generally accepted. It is unclear whether peripheral trauma can induce dystonia and other movement disorders. Some auhors support this debate [4] while others are strongly opposed.[5] We also recently observed a case of generalized myoclonus induced by peripheral trauma. Taken together, these cases may further solidify this as an under-recognized phenomenon. References 1. Costa J, Henriques R, Barroso C, et al. Upper limb tremor induced by peripheral nerve injury. Neurology 2006;67:1884-1886. 2. Dedic JS, Ivanovic NS, Svetel MV, et al. The differences between dystonical movement in primary and secondary dystonia.Mov Disord 2002;17(Suppl5):S305. 3. Frei KP, Pathak M, Jenkins SW, Truong DD. The natural history of posttraumatic torticollis. Mov Disord 2002;17(Suppl 5):S307 4. Jankovic J.Can peripheral trauma induce dystonia and other movement disorders? Yes! Mov Disord 2001; 16:7-12. 5. Weiner WJ. Can peripheral trauma induce dystonia? No! Mov Disord 2001; 16:13-22. Disclosure: The authors report no conflicts of interest.
Reply from the authors 27 June 2007
Mamede de Carvalho, Department of Neurology, Hospital de Santa Maria Av. Prof Egas Moniz. 1649-028 Lisbon Portugal, Joćo Costa, Joaquim Ferreira Send Correspondence to journal: Re: Reply from the authors mamedemg{at}mail.telepac.pt Mamede de Carvalho, et al.	We are grateful for the comments of Drs. Atadzhanov and Mwaba. They recognized our contribution to the discussion of the etiology of peripheral induced movement disorders. [1] They describe a severe dystonic tremor secondary to a peripheral trauma. Their case is unique because it occurred in an African adult patient. There are several other similar case reports published in the literature, in which a temporal association between trauma and the diagnosis of a movement disorder is mentioned. [4] We think that our case supports a robust causality between trauma and the induction of tremor. Surgical nerve damage was well documented and tremor was neurophysiologically characterized, in particular concerning modulation and persistence during sleep. Because it is methodologically difficult and probably unethical to conduct this kind of experimental research in humans, observational data will continue to play a crucial role in expanding our knowledge of this association. Disclosure: The author reports no conflicts of interest.
Upper limb tremor induced by peripheral nerve injury 12 March 2007
William J. Weiner, University of Maryland School of Medicine 22 S. Greene St, N4W6 Baltimore, MD 21201, Stephen G. Reich, MD Send Correspondence to journal: Re: Upper limb tremor induced by peripheral nerve injury wweiner{at}som.umaryland.edu William J. Weiner, et al.	The article by Costa et al is of considerable interest yet the designation of a post-traumatic upper limb tremor is not supported by the EMG or video. [1] The patient underwent a thoracotomy with resection of an extrapulmonary tumor and four months following this procedure developed unusual quasi-rhymthical movements of the posterolateral musculature of the chest wall. The movements do not entirely fit the definition of a tremor since they are often irregular, do not involve alternate contractions of opposing groups of muscles, persist during sleep, and are not particularly sinusoidal. [2,3] More importantly, they report that their EMG does not reveal abnormalities of the proximal arm muscles, but only abnormalities of the latissimus dorsi and serratus anterior muscles. Whatever the nature and classification of these tremor-like movements, they are not causing a proximal upper limb tremor as the authors state. The authors explain that there is controversy concerning the relationship between peripheral trauma and abnormal movements. [4] It is important to clarify and be precise about movement disorders ascribed to peripheral trauma. We are concerned that this paper will be cited in the future as evidence of a peripheral nerve injury causing an upper limb tremor. Nevertheless, we agree that this is a post-traumatic movement disorder but--unlike many reported cases--the association is supported by objective evidence of a peripheral nerve injury. References 1.Costa J, Henriques R, Barroso C, Ferreira J, Atalaia A, deCarvalho M. Upper Limb Tremor Induced by Peripheral Nerve Injury, Neurology, 2006; 67:1884-1886. 2. DeJong R. The Neurologic Examination Third Edition, Harper & Row, NY, 1969, pp. 535-540. 3. Marsden CD, Fahn S (Eds). Movement Disorders. Butterworth, Cornelius, 1982, pp. 198. 4. Weiner WJ. Can Peripheral Trauma Induce Dystonia? No! Movement Disorders 2001;16:13-22. Disclosure: The authors report no conflicts of interest.
Reply from the Authors 12 March 2007
Mamede de Carvalho, Institute of Molecular Medicine Faculty of Medicine, University of Lisbon, Portugal., Joćo Costa, Joaquim Ferreira Send Correspondence to journal: Re: Reply from the Authors mamedemg{at}mail.telepac.pt Mamede de Carvalho, et al.	We are grateful to Drs. Weiner and Reich regarding our report of a patient with a proximal upper-limb tremor after peripheral nerve lesion. [1] Their main criticism is that we describe a peripherally-driven tremor, not an essential or other central-driven tremor. We would stress that our patient's movement disorder persisted during sleep, only affected muscles dependent on the damaged nerves, and were not completely sinusoidal. This is not a typical case of central-driven tremor provoked by peripheral lesion. The process of denervation/reinnervation shown through serial EMGs evaluations could have produced changes in motoneuronal excitability. Peripherally generated tremors are usually action tremors, meaning that the muscle has to have some degree of activity for the tremor to appear. In our case, we think that the proximal muscles of the upper limb that were involved have always had some postural activity and, because of that, they were not completely at rest. This is suggested by our observations of polyphasic motor units firing regularly without volitional activation. In addition, the lattissimus dorsi and the serratus muscles can actually be antagonist in the control of the scapula. [5] The movements seemed quite rhythmic in our patient but Weiner and Reich claim they are quasi-rhythmic. We are not aware of an established limit for rhythmicity that could help to determine whether the reported movement was a tremor. Tremor is defined as “a rhythmic (periodic) movement of a body part”. [6] Observing this patient, the diagnosis of a proximal tremor seems appropriate. References 5. Florence FP, McCreary EK. Muscles: Testing and Function. Lippincott Williams & Wilkins, 1993. 6. Clinical Examinations in Neurology. 6th Edition. Mosby Year Book. St Louis. 1991, pp. 161-162. Disclosure: The authors report no conflicts of interest.