Prediction on affected upper extremity function in hemiplegic patients after thalamic hemorrhage using somatosensory evoked magnetic fields

Abstract

The aim of the present study was to investigate the prognostic value of somatosensory evoked magnetic fields (SEFs) at an acute stage on recovery of an affected upper extremity (UE) function as practicality in hemiplegic patients after thalamic hemorrhage. Nine hemiplegic patients after thalamic hemorrhage were enrolled in this study. Median nerve SEFs, evoked by electrical stimulation at the wrist of the affected UE, were measured using a 204 channel whole-head magnetoencephalography system within 72 hours after the onset of thalamic hemorrhage (acute stage). Assessments on the affected UE, which included the motor palsies of the UE and fingers (Brunnstrom's motor recovery stage: BS), sensory disturbance (the thumb localizing test) and UE function (the UE ability test), were performed at both the acute stage and 3 months after the onset of thalamic hemorrhage (chronic stage). Almost all the patients showing any median nerve SEF components that originated from the somatosensory cortex in the affected hemisphere and occurred between about 20 ms and 100 ms post-stimulus at the acute stage demonstrated good outcomes in the motor palsies (BSV), sensory disturbance (normal) and affected UE function (practical hand) at the chronic stage. In contrast, majority of patients not showing them at all demonstrated poor outcomes in the motor palsies (BSIII or less), sensory disturbance (severely impaired) and affected UE function (disabled hand) at the chronic stage. These results suggest that the findings of the median nerve SEFs at the acute stage would contribute to the early outcome prediction on the affected UE function in hemiplegic patients after thalamic hemorrhage.

Keywords: affected upper extremity function; prediction; somatosensory evoked magnetic fields; thalamic hemorrhage.

Fig. 1.

The median nerve SEF representative waveforms, components occurring between about 20 ms and 100 ms post-stimulus and source locations of the components with the shortest latency in the patients of the R group. Black arrows point to the median nerve SEF components with the shortest latency. Black arrows with a dashed line point to the median nerve SEF components after ones with the shortest latency. Circles represent the source locations of the median nerve SEF components with the shortest latency. White arrows point to the central sulcus. GOF, goodness-of-fit.

Fig. 2.

Relationship between the findings of the median nerve SEFs at the acute stage and the severity of the motor palsy of the affected upper extremity at both the acute and chronic stages. Each number in Fig. 2 represents Patient No. *, p<0.05.

Fig. 3.

Relationship between the findings of the median nerve SEFs at the acute stage and the severity of the motor palsy of the affected fingers at both the acute and chronic stages. Each number in Fig. 3 represents Patient No. *, p<0.05.

Fig. 4.

Relationship between the findings of the median nerve SEFs at the acute stage and the severity of the sensory disturbance of the affected upper extremity at both the acute and chronic stages. Each number in Fig. 4 represents Patient No. *, p<0.05.

Fig. 5.

Relationship between the findings of the median nerve SEFs at the acute stage and the severity of the affected upper extremity function at both the acute and chronic stages. Each number in Fig.5 represents Patient No. Practical A, practical hand A; Practical B, practical hand B, Assisted A, assisted hand A; Assisted B, assisted hand B; Assisted C, assisted hand C; Disabled, disabled hand; *, p<0.05.