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Biomedical subjects

A B Scott

Publications and source records attributed to A B Scott.

At least 19 recordsLinked to original sources
PubMed1992

Treatment of hemifacial spasm with botulinum toxin.

The effectiveness of botulinum toxin injections in 11 patients with hemifacial spasm was investigated in a prospective placebo-controlled blinded study. The patients were treated with four sets of injections to various facial muscles, selected by clinical evaluation. Three injections were with graded doses of toxin and one was with placebo. The order of injections was random and unknown to the patients. Results were scored both subjectively by patient assessment of symptoms and objectively by blinded review of videotapes made one month after each injection. Subjective improvement occurred after 79% of injections with botulinum toxin, regardless of dose of toxin. Only 1 patient improved after placebo. Objective improvement was seen after 84% of injections with botulinum toxin. No patient showed objective improvement after placebo injection. The most frequent side effect was facial weakness, seen after 97% of injections of botulinum toxin. Facial bruising (20%), diplopia (13%), ptosis (7%), and various other mild side effects were seen less frequently. Botulinum toxin appears to be an effective and safe method of therapy for hemifacial spasm.

Botulinum Toxins↗
PubMed1990

Botulinum treatment of strabismus following retinal detachment surgery.

Twenty patients with strabismus and diplopia following surgery for retinal detachment were treated by botulinum toxin injection of the eye muscles. Twelve patients had regained fusion with elimination of diplopia in the primary position at the time of examination, 5 to 96 months after treatment (mean, 24 months). Three patients had partial diplopia elimination, and five patients continued to have diplopia.

Adult↗
PubMed1990

Botulinum treatment of childhood strabismus.

Four hundred thirteen children ranging in age from 2 months to 12 years were treated for strabismus by botulinum injection of extraocular muscles. An average of 1.7 injections per patient was given. Follow-up at an average of 26 months after the last injection (minimum, 6 months) was available on 362 children (88%). The frequency of correction of 10 prism diopters (PD) or less in various groups of strabismus cases was: all 362 cases, 61%; all esotropia, 66%; infantile esotropia, 65%; and exotropia, 45%. Smaller deviations (10-20 PD) were more frequently corrected (73%) than were larger deviations (20-110 PD, 54%). The frequency of correction to 10 PD or less of previously operated cases was not different from that of unoperated cases. There was no globe perforation, amblyopia, or visual loss produced by the injection treatment in this series.

Botulinum Toxins↗
PubMed1988

Effects of botulinum A toxin on detrusor-sphincter dyssynergia in spinal cord injury patients.

We evaluated the ability of low doses of botulinum A toxin, an inhibitor of acetylcholine release at the neuromuscular junction, to denervate and relax the spastic rhabdosphincter in 11 men with spinal cord injury and detrusor-sphincter dyssynergia. Toxin concentration, injection volume, percutaneous versus cystoscopic injection of the sphincter and number of injections were evaluated in 3 treatment protocols. All 10 patients evaluated by electromyography after injection showed signs of sphincter denervation. Bulbosphincteric reflexes in the 10 patients evaluated after injection were more difficult to obtain, and they showed a decreased amplitude and normal latency. The urethral pressure profile in the 7 patients in whom it was measured before and after treatment decreased an average of 27 cm. water after toxin injections. Post-void residual urine volume decreased by an average of 146 cc after the toxin injections in 8 patients. In the 8 patients for whom it could be determined toxin effects lasted an average of 50 days. The toxin also decreased autonomic dysreflexia in 5 patients.

Adult↗
PubMed1987

Botulinum toxin chemodenervation in infants and children: an alternative to incisional strabismus surgery.

Eighty-two children aged 13 years or younger were given injections of botulinum toxin for horizontal strabismus. Improvement was achieved in all but one patient. Children younger than 1 year or older than 6 years of age received only topical drop anesthesia and no sedation. Young children generally required low-dose ketamine sedation. The technique typically undercorrects, so reinjection was necessary in 85% of the patients. There were no systemic complications. Side effects, lasting up to a few weeks, included transient ptosis and hypertropia caused by involvement of other extraocular muscles.

Botulinum Toxins↗
PubMed1975

Disinserted extraocular muscles.

In two patients, a muscle that slipped from the globe posteriorly created the clinical pattern of reduced rotation amplitude, reduced saccadic velocity, reduced active force, and increasing exophthalmos with gaze into the field of action of the muscle. The muscle was surgically identified by an electronic stimulator that caused the muscle to contract, thus allowing the surgeon to fell it pull on the forceps or see its traction on adjacent tissues.

Child↗
PubMed1975

Horizontal saccadic velocities in Duane's syndrome.

Horizontal ocular saccadic velocities were measured by electro-oculography in 33 patients with Duane's syndrome. In 28 patients with limited abduction associated with retraction on adduction (Type 1), abduction saccadic velocity was markedly reduced while adduct-on saccades were moderately slow. In three patients with exotropia and good abduction but associated limited adduction and retraction on adduction (Type 2), abduction velocity was good, while adduction saccadic speed was slow. In two patients with limited abduction and adduction with retraction on adduction (Type 3), abduction and adduction saccadic velocity was appreciably slow. Ocular electromyographic testing selected patients indicated that slow abduction saccades could be explained by absence of lateral rectus muscle recruitment, while slow adduction saccadic speed could be explained by paradoxical innervation of the lateral rectus muscle.

Duane Retraction Syndrome↗
PubMed1975

Muscle tension during unrestrained human eye movements.

1. Tensions in the horizontal rectus muscles have simultaneously and continuously been recorded during unrestricted eye movements in four strabismus patients, using force transducers small enough to be implanted in series between the tendons and their points of insertion on the globe. 2. Levels of tension required to maintain fixation at each position of gaze vary from a minimum of 8-12 g approximately 15 degrees outside of muscle's field of action to a maximum of around 40 g at extreme gaze within the muscle's field of action. When tension is plotted as a function of eye position, the static locus of fixation tension levels exhibits a parabolic relationship. 3. Tensions recorded during smooth following movements parallel or slightly exceed those of fixation. 4. At the onset of a saccade, tension in the agonist rises isometrically, then, as the eye moves, tension levels parallel those of fixation but with an isotonic increment of 15-25 g. At the end of the saccadic movement, tension falls essentially isometrically to the new fixation level. 5. Tension in the antagonist reveals an unexpected peak at the onset of a saccade. 6. For saccadic movements tension increments of 15-25 g above the fixation levels suffice to move the eye rapidly to a new position of gaze, regardless of the duration of the saccade and the location of the new fixation point. 7. Maximum and minimum levels of tension during normal fixation, following and saccadic movements, plotted as a function of eye position, form an operational envelope which defines the limits of muscle forces during normal eye movements. The lowest level of this envelope is the parabolic static locus of fixation tensions.

Adult↗