Neuroanatomical correlates of poststroke complex regional pain syndrome: a voxel-based lesion symptom-mapping study.

Complex regional pain syndrome (CRPS) is a common poststroke complication. However, the neural substrates associated with CRPS remain unclear. We investigated the neural correlates associated with poststroke CRPS using voxel-based lesion‒symptom mapping (VLSM) analysis. Among 145 patients with ischemic stroke, 35 were diagnosed with CRPS and categorized into the poststroke CRPS group, and the remaining 110 into the control group. We compared the clinical characteristics between the groups. VLSM analysis was performed to identify the brain region associated with the development of poststroke CRPS. The clinical findings suggested that the poststroke CRPS group had lower muscle strength; lower scores on Fugl‒Meyer assessment, Manual Function Test, Mini-Mental Status Examination; and higher incidence of absent somatosensory evoked potentials in the median nerve than the control group. The head of the caudate nucleus, putamen, and white matter complexes in the corona radiata were significantly associated with poststroke CRPS development in ischemic stroke patients. These results facilitate an understanding of poststroke CRPS pathophysiology. Monitoring patients with lesions in these structures may aid the prevention and early treatment of poststroke CRPS.

Early Detection of Diabetic Polyneuropathy Using Paired Stimulation Studies of the Sensory Nerves.

OBJECTIVE: This study seeks to use the relative refractory period, a sensitive parameter for detecting early change in peripheral polyneuropathies, as a tool for early detection of diabetic polyneuropathy. DESIGN: The relative refractory period of the median and sural sensory nerves was measured in 57 diabetic patients (male 31, female 26) and 23 healthy controls (male 16, female 7). The shortest interstimulus interval, where the latency of the response to the second stimulus recovers to normal, was defined as the relative refractory period. RESULTS: The relative refractory period of the median and sural nerves were significantly longer in diabetic patients (3.6 msec, P < 0.001, and 3.8 msec, P < 0.001, respectively) than in the control group (3.0 msec in both nerves). Relative refractory period values of both nerves were also significantly prolonged compared with the control group, even in diabetic patients without diabetic polyneuropathy based on conventional conduction studies (3.3 msec, P = 0.002, for median nerve; 3.5 msec, P < 0.001, for sural nerve) or without any clinical symptoms and signs (3.3 msec, P = 0.007, for median nerve; 3.5 msec, P = 0.001, for sural nerve). CONCLUSIONS: The relative refractory period was prolonged in diabetic patients even before other electrophysiologic abnormalities or clinical findings appeared. These results suggest that the relative refractory period can be a possible early indicator of diabetic polyneuropathy.

Complex Regional Pain Syndrome of Non-hemiplegic Upper Limb in a Stroke Patient: A Case Report.

Complex regional pain syndrome (CRPS) type I in stroke patients is usually known to affect the hemiplegic upper limb. We report a case of CRPS presented in an ipsilesional arm of a 72-year-old female patient after an ischemic stroke at the left middle cerebral artery territory. Clinical signs such as painful range of motion and hyperalgesia of her left upper extremity, swollen left hand, and dystonic posture were suggestive of CRPS. A three-phase bone scintigraphy showed increased uptake in all phases in the ipsilesional arm. Diffusion tensor tractography showed significantly decreased fiber numbers of the corticospinal tract and the spinothalamic tract in both unaffected and affected hemispheres. Pain and range of motion of the left arm of the patient improved after oral steroids with a starting dose of 50 mg/day.

Sonography of Carpal Tunnel Syndrome According to Pathophysiologic Type: Conduction Block Versus Axonal Degeneration.

OBJECTIVES: The purpose of this study was to investigate sonographic findings according to the pathophysiologic type in patients with carpal tunnel syndrome. METHODS: We retrospectively reviewed the records of 80 patients (148 hands) with carpal tunnel syndrome. Patients were classified into 3 groups according to electrophysiologic findings: (1) conduction block and conduction delay; (2) axonal degeneration; and (3) mixed. We used sonographic evaluations to assess the cross-sectional area at the distal wrist crease and the distal forearm and the wrist-to-forearm ratio of the median nerve. RESULTS: Patients with axonal degeneration had significantly larger cross-sectional areas and wrist-to-forearm ratios than those with a conduction block (P < .05). The increased wrist-to-forearm ratio correlated with a reduced amplitude of the sensory nerve action potential, which reflects the degree of axonal degeneration. CONCLUSIONS: The cross-sectional area and wrist-to-forearm ratio were associated with the pathophysiologic type of carpal tunnel syndrome, with larger nerve swellings seen in patients with axonal degeneration compared with those with demyelinating lesions. In addition to helping in the localization of the nerve lesion, sonography may indicate the type of nerve lesion.