Biomedical subjects
Publications and source records attributed to R L Harmon.
A patient with a post-traumatic midbrain haemorrhagic lesion documented by magnetic resonance imaging (MRI) presented with a combined resting-kinetic contralateral upper extremity tremor. The resting tremor component responded to levodopa/carbidopa, while the kinetic component improved with the addition of carbamazepine.
The electrodiagnostic records of 49 patients with ulnar neuropathy at the elbow (UNE) on at least one side were reviewed. Of these, 18 (36.7%) had contralateral and 1 (2.0%) had probable contralateral involvement, for a total of 19 patients (38.8%) with bilateral UNE. The upper extremity presenting symptoms were unilateral in 13 (68.4%) of the patients with bilateral UNE. Differences in associated clinical history data and concurrent electrodiagnostic findings were not clinically or statistically significant between the unilateral and bilateral UNE groups. This pilot study suggests the incidence of UNE bilaterality may be high in some populations and that, when UNE is encountered electrodiagnostically, the contralateral extremity should also be tested. Further studies to determine what factors are related to the bilaterality of UNE appear indicated.
Electromyographic (EMG) evidence of inappropriate muscle activity (IMA) in the cricothyroid (CT) and vocalis (V) (thyroarytenoid) muscles was correlated with clinical voice measures in 32 patients with spasmodic dysphonia (SD). Subjective voice rating and quantified fluency and laryngeal diadochokinesis measures were obtained prior to botulinum toxin (Botox) injection into the V muscles. Pre-Botox EMG was performed using a monopolar needle electrode. Each muscle was sequentially examined at rest, during vocal click, scale, sustained "E" at different pitches, and repeated "E" voicings for brief periods. A three point EMG severity scale was used to grade the amount of IMA seen in each muscle. EMG evaluation showed no evidence of lower motor neuron involvement but did reveal IMA in 81.3% of the subjects. There were no significant correlations for the patients between different EMG-based IMA severity scales and the measures of voice quality and sound production. EMG did discriminate between predominantly adductor and abductor SD pattern types, but could not correctly differentiate a mixed SD group. Those patients with adductor SD displayed IMA in the V and CT muscles, while those with abductor SD displayed more IMA in the CT than the V muscles. Sequential EMG assessment of CT and V IMA in SD did not predict clinical severity or outcome following Botox injection into the V muscles.
Using a combined concentric (CN) and modified single fiber (MSF) electromyographic needle electrode with both recording surfaces at the tip approximately 25 microns apart, 24 motor unit potentials (MUPs) were recorded from one extensor digitorum communis muscle, triggering from either the CN or MSF channel in equal numbers and averaging both CN and MSF recordings. Filter settings were 20-10,000 Hz. Correlations of MUP amplitude, phases, turns, negative turns (NTs), and main spike duration, but not rise time or duration, between the CN and MSF recordings were statistically significant (P < 0.05). Mean +/- SD numbers of estimated single fiber potentials (ESFPs) and NTs for the MSF recordings were 1.17 +/- 0.38 and 1.54 +/- 0.72. Correlations between numbers of ESFPs and turns, NTs and phases, NTs and turns, and NT and main spike duration for the MSF and CN MUP recordings, respectively, were statistically significant (P < 0.05). The study findings using these techniques continue to support evidence that one or a few muscle fibers contribute to the main spike component of the MUP.
Using a combined concentric (CN) and modified single fiber (MSF) electromyography (EMG) needle electrode with both recording surfaces at the tip approximately 25 microns apart, 30 motor unit action potentials (MUAP) were recorded from one extensor digitorum communis (EDC) muscle, triggering from the CN and averaging both the CN and MSF recordings. Correlations of MUAP amplitude (r = 0.767), number of turns (r = 0.839), and number of negative-going-positive-going turn (NT) (r = 0.737) between the CN and MSF recordings were statistically significant (p < 0.001). For NTs common to both recordings, correlations of rise time (r = 0.866), amplitude (r = 0.816), and interpeak interval (IPI) (r = 0.999) were statistically significant (p < 0.001). Mean +/- SD single fiber potentials (SFP), approximate SFP with rise times less than 500 microseconds, and NTs for the MSF recordings and NTs for the CN recordings were 0.73 +/- 0.69, 1.20 +/- 0.48, 1.83 +/- 0.87, and 1.93 +/- 0.78, respectively. This study supports evidence that one or a few SFP contribute to the spike component of the MUAP.
While peroneal and tibial neuropathies have been described as a complication of total knee arthroplasty (TKA), a computerized literature search failed to reveal any previously reported cases of associated sacral plexopathy or sciatic neuropathy. This case report describes the diagnosis and management of a patient found to have evidence of a right sacral plexopathy and a left sciatic neuropathy, following bilateral TKA. This case suggests that these may be rare complications of TKA.