Miriam Hwang

Combined Passive Stretching and Active Movement Rehabilitation of Lower-Limb Impairments in Children With Cerebral Palsy Using a Portable Robot

Background. Ankle impairments are closely associated with functional limitations in children with cerebral palsy (CP). Passive stretching is often used to increase the range of motion (ROM) of the impaired ankle. Improving motor control is also a focus of physical therapy. However, convenient and effective ways to control passive stretching and motivate active movement training with quantitative outcomes are lacking. Objective. To investigate the efficacy of combined passive stretching and active movement training with motivating games using a portable rehabilitation robot. Methods. Twelve children with mild to moderate spastic CP participated in robotic rehabilitation 3 times per week for 6 weeks. Each session consisted of 20 minutes of passive stretching followed by 30 minutes of active movement training and ended with 10 minutes of passive stretching. Passive ROM (PROM), active ROM (AROM), dorsiflexor and plantarflexor muscle strength, Selective Control Assessment of the Lower Extremity, and functional outcome measures (Pediatric Balance Scale, 6-minute walk, and Timed Up-and-Go) were evaluated before and after the 6-week intervention. Results. Significant increases were observed in dorsiflexion PROM (P = .002), AROM (P = .02), and dorsiflexor muscle strength (P = .001). Spasticity of the ankle musculature was significantly reduced (P = .01). Selective motor control improved significantly (P = .005). Functionally, participants showed significantly improved balance (P = .0025) and increased walking distance within 6 minutes (P = .025). Conclusions. Passive stretching combined with engaging in active movement training was of benefit in this pilot study for children with CP. They demonstrated improvements in joint biomechanical properties, motor control performance, and functional capability in balance and mobility.

Changes of calf muscle-tendon biomechanical properties induced by passive-stretching and active-movement training in children with cerebral palsy

Biomechanical properties of calf muscles and Achilles tendon may be altered considerably in children with cerebral palsy (CP), contributing to childhood disability. It is unclear how muscle fascicles and tendon respond to rehabilitation and contribute to improvement of ankle-joint properties. Biomechanical properties of the calf muscle fascicles of both gastrocnemius medialis (GM) and soleus (SOL), including the fascicle length and pennation angle in seven children with CP, were evaluated using ultrasonography combined with biomechanical measurements before and after a 6-wk treatment of passive-stretching and active-movement training. The passive force contributions from the GM and SOL muscles were separated using flexed and extended knee positions, and fascicular stiffness was calculated based on the fascicular force-length relation. Biomechanical properties of the Achilles tendon, including resting length, cross-sectional area, and stiffness, were also evaluated. The 6-wk training induced elongation of muscle fascicles (SOL: 8%, P = 0.018; GM: 3%, P = 0.018), reduced pennation angle (SOL: 10%, P = 0.028; GM: 5%, P = 0.028), reduced fascicular stiffness (SOL: 17%, P = 0.128; GM: 21%, P = 0.018), decreased tendon length (6%, P = 0.018), increased Achilles tendon stiffness (32%, P = 0.018), and increased Youngs modulus (20%, P = 0.018). In vivo characterizations of calf muscles and Achilles tendon mechanical properties help us better understand treatment-induced changes of calf muscle-tendon and facilitate development of more effective treatments.

Frequency and severity of carpal tunnel syndrome according to level of cervical radiculopathy: Double crush syndrome?

OBJECTIVE The double crush hypothesis (DC) proposes that a proximal lesion along an axon predisposes it to injury at a more distal site along its course through impaired axoplasmic flow. The frequency and severity of carpal tunnel syndrome (CTS) according to the level of cervical radiculopathy were investigated to evaluate the hypothesis of DC. METHODS The frequency of CTS was investigated in 277 patients with C6, C7 or C8 radiculopathies and correlation between CTS and radiculopathy level was determined. We also investigated whether the degrees of abnormal sensory responses were more severe in C6, C7 radiculopathies and whether motor responses were more severe in C8 radiculopathy. RESULTS Thirty-nine patients were diagnosed with CTS and concomitant cervical radiculopathy at the C6, 7, or C8 root levels. The frequency of coexisting CTS was not statistically different according to the level of radiculopathy. The electrophysiologic results revealed no significant correlation between median sensory parameters and C6, C7 cases, and no relationship was observed between median motor responses and C8 radiculopathy. CONCLUSIONS The frequency and electrophysiologic data of CTS analyzed according to cervical radiculopathy level do not support a neurophysiological explanation. SIGNIFICANCE Based on this study, the DC hypothesis could not be supported.

Referred pain pattern of the pronator quadratus muscle.

&NA; Pain patterns of the myofascial trigger points (TrP) for most muscles of the forearm have been documented. However, there are no published reports on the referred pain patterns for the pronator quadratus (PQ) muscle. The purpose of this study was to determine the referred pain pattern of the TrP in the PQ. Thirty‐five arms of 35 healthy adult volunteers with no history of neck pain, arm pain or paresthesia were studied. Following skin sterilization, a Teflon‐coated syringe needle was inserted into the PQ of the non‐dominant forearm under electromyographic guidance, and 0.3 mL of 6% hypertonic saline was injected. Subjects drew in their pain areas on a pain diagram, and this drawing was transferred into the Pain Chart System® for analysis. Two main pain patterns were observed. The most common pattern involved pain spreading both distally and proximally from the injection site, along the medial aspect of the forearm (57%). In half of these cases, the pain area extended to the medial epicondyle proximally and the fifth digit distally. The second main pattern revealed pain spreading distally to the third and/or fourth finger (29%). The pain patterns originating from the PQ resemble the C8‐T1 dermatomes, and ulnar and median nerve sensory distributions. Thus, myofascial pain of the PQ should be considered as a possible cause of pain in the medial forearm and hand, especially when no other neurological abnormalities are present.

Meralgia paresthetica caused by hip-huggers in a patient with aberrant course of the lateral femoral cutaneous nerve.

“Hip‐huggers” may be a precipitating factor for meralgia paresthetica (MP), especially in thin persons with an aberrant pathway of the lateral femoral cutaneous nerve (LFCN). We describe a 25‐year‐old woman with a long‐standing history of MP caused by an abnormal course of the LFCN and tight trousers, specifically hip‐huggers. Ultrasonography was useful for detecting the lesion site and the abnormal pathway of the LFCN. After neurectomy of the LFCN, most of the symptoms of MP were relieved, but mild hypesthesia remained in the lateral thigh. Muscle Nerve, 2007

Referred pain pattern of the abductor pollicis longus muscle.

Hwang M, Kang YK, Shin JY, Kim DH: Referred pain pattern of the abductor pollicis longus muscle. Am J Phys Med Rehabil 2005;84:593–597. Objective:To determine the referred pain pattern of the abductor pollicis longus muscle. Design:Intramuscular hypertonic saline was injected into the abductor pollicis longus of 15 healthy adults to induce muscle pain. Subjects completed pain drawings depicting the pain distribution. The drawings were transferred into the Pain Chart System for analysis. Results:Referred pain distributions were as follows: the radial aspect of the wrist (61.9%), the dorsal aspects of the third and fourth fingers (14.3%), and a combination of the two distribution patterns (23.8%). Conclusion:Referred pain patterns of the abductor pollicis longus resemble the C6, 7, and 8 dermatomes, the superficial radial sensory nerve distribution, and are very similar to the area of pain experienced in de Quervain’s tenosynovitis. Thus, identification of the abductor pollicis longus trigger point should be considered in pain of the radial aspect of the wrist and thumb, especially when no other neurologic abnormalities or inflammatory conditions are present.

Efficacy of robotic rehabilitation of ankle impairments in children with cerebral palsy

The current study introduces a novel rehabilitation robot for treatment of impaired ankle in children with cerebral palsy (CP). The treatment consisted of passive stretching under intelligent control and active movement training with motivating game-playing using the portable robot. After 18 sessions of training (3 sessions/week for 6 weeks), we found significant improvement in 12 children with CP in terms of improved passive and active ranges of motion, selective motor control and mobility functions. The positive outcomes of this study along with the improvements in motor control and functional activities suggest that robotic rehabilitation provides a useful and convenient option of treatment in clinic or patient home for more accessible and frequent rehabilitation.

Reference values of fractionated neurography of the ulnar nerve at the wrist in healthy subjects

OBJECTIVE This study is designed to derive a normative database for nerve conduction values of the ulnar nerve in the wrist. METHODS Ulnar nerve study at the wrist (UNSW) was performed in 204 hands of 102 control subjects. The UNSW was composed of motor and sensory tests. Motor UNSW was done with first dorsal interosseous muscle recording. Sensory UNSW was performed antidromically with fifth finger recording. The 3 stimulation points were 2 cm proximal to the pisiform, just lateral to pisiform, and 3 cm distal to the pisiform. RESULTS Mean latency differences in the proximal and distal segments were 0.4 +/- 0.1 and 0.5 +/- 0.1 ms in motor UNSW and 0.4 +/ -0.1 and 0.5 +/- 0.1 ms in sensory UNSW. The 95th percentile values for motor and sensory UNSW were 0.5 ms in the proximal segment and 0.7 ms in the distal segment. CONCLUSIONS When the 95-percentile value was considered as the normal upper limit, the criteria of abnormality for motor and sensory UNSW were greater than 0. 5 ms in the proximal segment and greater than 0.7 ms in the distal segment. SIGNIFICANCE The normative values of UNSW may be useful in screening for ulnar neuropathy at the wrist.

Medial and lateral branches of the superficial radial nerve: Cadaver and nerve conduction studies

OBJECTIVE To establish a reliable technique for nerve conduction study (NCS) of medial and lateral branches of the superficial radial nerve (SRN). METHODS The distribution of SRN and its branches were examined in 10 cadavers. Based on the cadaveric study, anti-dromic nerve conduction studies were performed on 31 healthy subjects. RESULTS The SRN became superficial approximately 8.4 cm from the radial styloid process (RS) and divided into medial and lateral branches 4.9 cm proximal to RS. The medial branch divided into two branches: proximal to extensor pollicis longus (EPL) tendon in 16 hands. The lateral branch ran parallel and 0.2 cm lateral to abductor pollicis longus (APL) tendon. Sensory nerve action potential (SNAP) was significantly shorter in latencies when recording over snuff box, compared with that from the EPL and APL tendons. SNAP obtained from APL tendon was significantly smaller in amplitude, compared with those from snuff box and EPL tendon. CONCLUSIONS Anti-dromic stimulation of SRN should be performed 10 cm proximal to the recording electrode. The optimal recording position for each branch of SRN is snuff box for medial branch, and lateral to APL tendon for lateral branch. SIGNIFICANCE The SRN can be evaluated appropriately by NCS of medial and lateral branches of SRN.

Amplitude Ratio of Ulnar Sensory Nerve Action Potentials in Segmental Conduction Study : Reference Values in Healthy Subjects and Diagnostic Usefulness in Patients with Ulnar Neuropathy at the Elbow

Kwon H-K, Lee HJ, Hwang M, Lee S-H: Amplitude ratio of ulnar sensory nerve action potentials in segmental conduction study: reference values in healthy subjects and diagnostic usefulness in patients with ulnar neuropathy at the elbow. Am J Phys Med Rehabil 2008;87:642–646. Objective:To determine normal values for the amplitude ratio of sensory nerve action potential (SNAP) from an ulnar sensory segmental nerve conduction study, and to the evaluate usefulness in the diagnosis of mild-degree ulnar neuropathy at the elbow (UNE). Design:Segmental sensory conduction study of the ulnar nerve was performed in 71 healthy subjects. Peak latency and baseline to peak amplitudes were measured. The amplitude ratio of below-elbow to wrist (BE/W) stimulations and above-elbow (AE) to below-elbow stimulations (BE) were calculated. Normal cutoff values were obtained by subtracting 2 SD from the mean value, and these values were applied to 22 symptomatic UNE cases. The amplitude ratio was also obtained in six subjects with C8 radiculopathy. Results:The amplitude ratios of BE/W and AE/BE were 0.61 ± 0.08 and 0.82 ± 0.08, respectively. The cutoff value of BE/W was 0.45, and that of AE/BE was 0.65. The amplitude ratio of BE/W showed a weak correlation to the length of the forearm segment (r = −0.25, P < 0.05). Five of the 22 UNE patients revealed only reduced amplitude ratios of SNAP across the lesion, whereas all the patients with C8 radiculopathy showed normal amplitude ratios of ulnar SNAP. Conclusions:The amplitude ratio of ulnar SNAPs may be useful in the diagnosis of mild ulnar neuropathy with only sensory symptoms and normal segmental motor conduction.