Globus pallidus internus activity during simultaneous bilateral microelectrode recordings in status dystonicus

The changing face of reported status dystonicus - A systematic review

BACKGROUND

Status Dystonicus (SD) represents the most severe end of the spectrum of dystonia. We aimed to explore whether reported features of cases of SD have changed over time.

METHODS

A systematic review of cases of SD reported from 2017 to 2023 and comparison of features to data extracted from 2 previous literature reviews (epochs 2012-2017 and pre-2012).

RESULTS

From 53 papers, a total 206 SD episodes in 168 patients were identified from 2017 to 2023. Combining data from all 3 epochs, a total of 339 SD episodes were reported from 277 patients. SD episodes occurred mostly in children, with a trigger identified in 63.4% of episodes, most commonly infection/inflammation. Most reported underlying aetiologies were genetic (e.g. 49.5% between 2017 and 2023), including new associated aetiologies in each epoch. Deep Brain Stimulation (DBS)-related SD increased over time. Neurosurgical interventions were more frequently reported in later epochs. Across the epochs, return to or improvement post SD episode, compared to baseline was reported above 70%. Reported mortality was 4.9% most recently, compared to 11.4% and 7.9%, previously.

CONCLUSIONS

SD episodes reported have more than doubled in the last 5 years. Reports of medication change-induced SD have become less frequent, whilst episodes of DBS-related SD have become more frequent. More dystonia aetiologies, including novel aetiologies have been reported in recent cohorts, reflecting advances in genetic diagnosis. Neurosurgical interventions are increasingly reported in the management of SD episodes, including novel use of intraventricular baclofen. Overall outcomes from SD remain largely unchanged over time. No prospective epidemiological studies of SD were identified.

Spinal Cord Injury-Induced Changes in Encoding and Decoding of Bipedal Walking by Motor Cortical Ensembles

Recent studies have shown that motor recovery following spinal cord injury (SCI) is task-specific. However, most consequential conclusions about locomotor functional recovery from SCI have been derived from quadrupedal locomotion paradigms. In this study, two monkeys were trained to perform a bipedal walking task, mimicking human walking, before and after T8 spinal cord hemisection. Importantly, there is no pharmacological therapy with nerve growth factor for monkeys after SCI; thus, in this study, the changes that occurred in the brain were spontaneous. The impairment of locomotion on the ipsilateral side was more severe than that on the contralateral side. We used information theory to analyze single-cell activity from the left primary motor cortex (M1), and results show that neuronal populations in the unilateral primary motor cortex gradually conveyed more information about the bilateral hindlimb muscle activities during the training of bipedal walking after SCI. We further demonstrated that, after SCI, progressively expanded information from the neuronal population reconstructed more accurate control of muscle activity. These results suggest that, after SCI, the unilateral primary motor cortex could gradually regain control of bilateral coordination and motor recovery and in turn enhance the performance of brain–machine interfaces.