Pseudoathetosis in a patient with cervical myelitis: neurophysiologic and functional MRI studies

Pseudodystonia: A new perspective on an old phenomenon

Pseudodystonia represents a wide range of conditions that mimic dystonia, including disorders of the peripheral nervous system, spinal cord, brainstem, thalamus, cortex and non-neurological conditions such as musculoskeletal diseases. Here, we propose a definition of pseudodystonia and suggest a classification based on underlying pathophysiological mechanisms. We describe phenomenology of different forms of pseudodystonia and point to distinctions between dystonia and pseudodystonia as well as challenging issues that may arise in clinical practice. The term pseudodystonia can be used to describe abnormal postures, repetitive movements or both, in which results of clinical, imaging, laboratory or electrophysiological investigations provide definite explanation of symptoms which is not compatible with dystonia. Pseudodystonia can be classified into non-neurological disorders of the musculoskeletal system, disorders of sensory pathways, disorders of motor pathways and compensatory postures in other neurological diseases. Presence of associated neurological findings in the affected body part is the key towards diagnosis of pseudodystonia. Additional supporting features are the presence of fixed postures, the absence of sensory trick, acute mode of onset and severe pain. Worsening on eye closure, traditionally considered typical for pseudodystonia, is not always present and can also appear in dystonia. It is challenging to separate dystonia and pseudodystonia in patients with thalamic lesions or corticobasal syndrome, where abnormal postures coexist with sensory loss. Many cases of pseudodystonia are treatable. Therefore, it is essential to consider pseudodystonia in a differential diagnosis of abnormal postures until a detailed neurological examination rules it out.

Cervical demyelinating lesion presenting with choreoathetoid movements and dystonia

Pseudoathetosis and dystonia are rare manifestations of spinal cord disease that have been already reported in lesions involving the posterior columns at the cervical level. We report two patients with a cervical demyelinating lesion at C3-C4 level presenting with hand dystonia and pseudoathetoid movements. The movement disorder disappeared after steroid treatment. The cases we described highlight the importance of identifying secondary causes of movement disorders that can be reversible with appropriate therapy.

Pseudoathetosis: report of three patients

We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.

Pseudoathetosis caused by migrated cervical disc

Although pseudoathetosis has been described in various conditions, it has been rarely reported in patients with epidural lesions. We report the first case of a patient with pseudoathetosis caused by a migrated cervical disc. The patient was a 76-year-old woman who presented with progressive clumsiness of the hands and athetotic movements. Electrophysiological studies revealed normal peripheral nerve conduction and delayed and attenuated cortical SEPs. Spinal MRI revealed an epidural mass with gadolinium enhancement at the C3-4 level. An anterior cervical surgery disclosed a migrated disc, and its removal resulted in a marked improvement. Migrated cervical disc should be considered in patients with a profound sensory loss and pseudoathetosis in the hands, because this condition is treatable.

Trauma-induced spinal vascular event producing hemipseudoathetosis

We report on a patient with spinal pseudoathetosis secondary to posterior column vascular incident and physical injury. This unusual case highlights sensory system abnormalities as a cause of movement disorders.

Beneficial effect of donepezil on sensorimotor function after stroke

Pharmacotherapy of poststroke sensorimotor deficits is currently used alone or combined with physiotherapy to promote recovery of mobility problems. This case study examined the effectiveness of donepezil hydrochloride (HCl) administered to a stroke patient with chronic, dense, left sensorimotor deficit. The patient received donepezil HCl (5 mg daily for 4 wk, followed by 10 mg daily for 12 wk) but no physiotherapy. Baseline and posttreatment evaluations were performed with the Fugl-Meyer scale and the Rivermead Mobility Index. One month after starting donepezil HCl (10 mg/day), sensorimotor function improved dramatically in the hemiplegic lower limb and shoulder. It was concluded that donepezil HCl may be an effective treatment for improving sensorimotor function in chronic stroke patients. Randomized controlled trials are required to support these preliminary findings.

Involvement of the motor cortex in pseudochoreoathetosis

The pathophysiological background of involuntary movements in pseudochoreoathetosis is unclear. We therefore recorded in four patients with pseudochoreoathetosis and in six age-matched controls cortical activity with a whole-head magnetoencephalography (MEG) system and surface EMGs from hand muscles. Subjects performed the following tasks: 1) rest, and 2) constant finger stretch during forearm elevation; controls additionally simulated pseudochoreoathetotic finger movements. During rest, the patients showed involuntary finger movements associated with excessive MEG-EMG coherence at frequencies between 6 and 20 Hz, whereas coherence in controls simulating pseudochoreoathetotic movements did not exceed noise level (P < 0.02). During finger stretch, MEG-EMG coherence in patients was similar to that of controls. Cortical sources of MEG-EMG coherence in patients were localized in the contralateral motor cortex. We conclude that pseudochoreoathetosis is associated with pathologically increased corticomuscular coherence and thus differs, neurophysiologically, from voluntarily simulated pseudochoreoathetotic movements. The enhanced MEG-EMG coherence in pseudochoreoathetosis probably reflects a pathologically strong motor cortical drive of spinal motorneurons after deafferentation.