Assistant force compensation for hand movement of patients by using exogenous signals and/or neurophysiological signals

Background: Binasal Occlusion (BNO) is a clinical technique used by many neurorehabilitative optometrists in patients with mild traumatic brain injury (mTBI) and increased visual motion sensitivity (VMS) or visual vertigo. BNO is a technique in which partial occluders are added to the spectacle lenses to suppress the abnormal peripheral visual motion information. This technique helps in reducing VMS symptoms (i.e., nausea, dizziness, balance difficulty, visual confusion). Case Report: A 44-year-old AA female presented for a routine eye exam with a history of mTBI approximately 33 years ago. She was suffering from severe dizziness for the last two years that was adversely impacting her ADLs. The dizziness occurred in all body positions and all environments throughout the day. She was diagnosed with vestibular hypofunction and had undergone vestibular therapy but reported little improvement. Neurological exam revealed dizziness with both OKN drum and hand movement, especially in the left visual field. BNO technique resulted in immediate relief of her dizziness symptoms. Conclusion: To our knowledge, this is the first case that illustrates how the BNO technique in isolation can be beneficial for patients with mTBI and vestibular hypofunction. It demonstrates the success that BNO has in filtering abnormal peripheral visual motion in these patients.

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Context-dependent relationship in high-resolution micro-ECoG studies during finger movements

Journal of Neurosurgery ◽

10.3171/2019.1.jns181840 ◽

2020 ◽

Vol 132 (5) ◽

pp. 1358-1366

Author(s):

Chao-Hung Kuo ◽

Timothy M. Blakely ◽

Jeremiah D. Wander ◽

Devapratim Sarma ◽

Jing Wu ◽

...

Keyword(s):

High Resolution ◽

Sensorimotor Cortex ◽

Index Finger ◽

Hand Movement ◽

Cortical Activation ◽

Hand Movements ◽

Finger Movements ◽

Thumb Movement ◽

Neurosurgical Patients ◽

The Relationship

OBJECTIVEThe activation of the sensorimotor cortex as measured by electrocorticographic (ECoG) signals has been correlated with contralateral hand movements in humans, as precisely as the level of individual digits. However, the relationship between individual and multiple synergistic finger movements and the neural signal as detected by ECoG has not been fully explored. The authors used intraoperative high-resolution micro-ECoG (µECoG) on the sensorimotor cortex to link neural signals to finger movements across several context-specific motor tasks.METHODSThree neurosurgical patients with cortical lesions over eloquent regions participated. During awake craniotomy, a sensorimotor cortex area of hand movement was localized by high-frequency responses measured by an 8 × 8 µECoG grid of 3-mm interelectrode spacing. Patients performed a flexion movement of the thumb or index finger, or a pinch movement of both, based on a visual cue. High-gamma (HG; 70–230 Hz) filtered µECoG was used to identify dominant electrodes associated with thumb and index movement. Hand movements were recorded by a dataglove simultaneously with µECoG recording.RESULTSIn all 3 patients, the electrodes controlling thumb and index finger movements were identifiable approximately 3–6-mm apart by the HG-filtered µECoG signal. For HG power of cortical activation measured with µECoG, the thumb and index signals in the pinch movement were similar to those observed during thumb-only and index-only movement, respectively (all p > 0.05). Index finger movements, measured by the dataglove joint angles, were similar in both the index-only and pinch movements (p > 0.05). However, despite similar activation across the conditions, markedly decreased thumb movement was observed in pinch relative to independent thumb-only movement (all p < 0.05).CONCLUSIONSHG-filtered µECoG signals effectively identify dominant regions associated with thumb and index finger movement. For pinch, the µECoG signal comprises a combination of the signals from individual thumb and index movements. However, while the relationship between the index finger joint angle and HG-filtered signal remains consistent between conditions, there is not a fixed relationship for thumb movement. Although the HG-filtered µECoG signal is similar in both thumb-only and pinch conditions, the actual thumb movement is markedly smaller in the pinch condition than in the thumb-only condition. This implies a nonlinear relationship between the cortical signal and the motor output for some, but importantly not all, movement types. This analysis provides insight into the tuning of the motor cortex toward specific types of motor behaviors.

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