Exploratory study on the effects of a robotic hand rehabilitation device on changes in grip strength and brain activity after stroke.

BACKGROUND: The brain mechanisms underlying successful recovery of hand fuenction after stroke are still not fully understood, although functional MRI (fMRI) studies underline the importance of neuronal plasticity. METHODS: We explored potential changes in brain activity in 7 patients with subacute to chronic stroke (69 ± 8 years) with moderate- to high-grade distal paresis of the upper limb (Motricity Index: 59.4) after standardized robotic finger-hand rehabilitation training, in addition to conventional rehabilitation therapy for 3 weeks. Behavioral and fMRI assessments were carried out before and after training to characterize changes in brain activity and behavior. RESULTS: The Motricity Index (pre: 59.4, post: 67.2, P < .05) and grip force (pre: 7.26, post: 11.87, P < .05) of the paretic hand increased significantly after rehabilitation. On fMRI, active movement of the affected (left) hand resulted in contralesional (ie, ipsilateral) activation of the primary sensorimotor cortex prior to rehabilitation. After rehabilitation, activation appeared "normalized," including the ipsilesional primary sensorimotor cortex and supplementary motor area (SMA). No changes and no abnormalities of activation maps were seen during movement of the unaffected hand. Subsequent region-of-interest analyses showed no significant ipsilesional activation increases after rehabilitation. CONCLUSION: Despite behavioral improvements, we failed to identify consistent patterns of functional reorganization in our sample. This warrants caution in the use of fMRI as a tool to explore neural plasticity in heterogeneous samples lacking sufficient statistical power.

Epstein-Barr virus encephalitis presenting with a tumor-like lesion in an immunosuppressed transplant recipient.

Epstein-Barr virus (EBV) associated central nervous system (CNS) infection is a rare disease. We report an atypical manifestation of EBV encephalitis initially presenting with a tumor-like lesion of the optic tract in an immunocompromised patient 8 years after a combined kidney and pancreas transplantation had been performed. Polymerase chain reaction (PCR) in the cerebrospinal fluid (CSF) and antibody testing confirmed the diagnosis of EBV encephalitis, most likely as a consequence of a reactivated persistent EBV infection. After cessation of the immunosuppressive therapy and induction of treatment with ganciclovir, clinical and magnetic resonance imaging (MRI) findings rapidly improved.

Brain motor system function in a patient with complete spinal cord injury following extensive brain-computer interface training.

Although several features of brain motor function appear to be preserved even in chronic complete SCI, previous functional MRI (fMRI) studies have also identified significant derangements such as a strongly reduced volume of activation, a poor modulation of function and abnormal activation patterns. It might be speculated that extensive motor imagery training may serve to prevent such abnormalities. We here report on a unique patient with a complete traumatic SCI below C5 who learned to elicit electroencephalographic signals beta-bursts in the midline region upon imagination of foot movements. This enabled him to use a neuroprosthesis and to "walk from thought" in a virtual environment via a brain-computer interface (BCI). We here used fMRI at 3T during imagined hand and foot movements to investigate the effects of motor imagery via persistent BCI training over 8 years on brain motor function and compared these findings to a group of five untrained healthy age-matched volunteers during executed and imagined movements. We observed robust primary sensorimotor cortex (SMC) activity in expected somatotopy in the tetraplegic patient upon movement imagination while such activation was absent in healthy untrained controls. Sensorimotor network activation with motor imagery in the patient (including SMC contralateral to and the cerebellum ipsilateral to the imagined side of movement as well as supplementary motor areas) was very similar to the pattern observed with actual movement in the controls. We interpret our findings as evidence that BCI training as a conduit of motor imagery training may assist in maintaining access to SMC in largely preserved somatopy despite complete deafferentation.