Quality of voice after treatment for T1A glottic squamous cell carcinoma was studied in two matched groups of males treated either with CO2 laser cordectomi (n = 18, mean age 65.2 years) or with full dose radiotherapy (n = 18, mean age 65.1 years). All patients had histologically verified invasive squamous cell carcinoma. Fifteen male patients (mean age 63.9 years) without laryngeal disorders were used as controls. Voice recordings prior to treatment, and both at 3 months and at 2 years after completed treatment were analyzed. Acoustic measures of shimmer, jitter, breathiness, harmonic-to-noise ratio and fundamental frequency (F0) average were calculated with the Soundscope program. Two plain measures were also used: time required to read a running speech voice sample, and number of breaths. Perceptual voice analysis was performed blindly by two groups of listeners, Group A (4 experienced listeners) and Group B (4 naive listeners). Group A estimated quality of voice according to a modified GRBAS score, whereas Group B estimated Grade only. We found voice quality both at 3 months and at 2 years after radiotherapy to be significantly better than after laser treatment, as assessed by the acoustic variables breathiness, jitter, F0 average, running speech voice sample reading time and number of breaths. The perceptual variables Grade (Group A and B), Breathiness, Asthenia and Strain were also significantly better after radiotherapy.
SUMMARY1. In albino rats the botulinum poisoned gastrocnemius muscle was supplied with an accessory motor nerve in order to investigate whether muscle fibres with structurally intact but non-transmitting synapses would accept additional innervation. As a control similar operations were made in unpoisoned rats.2. One to three months after nerve implantation the muscles were examined histologically for the presence of a new end-plate zone. In botulinum treated muscles 1662 + 165 (mean + S.D.) of new end-plates were found. In the control animals only a few (90 + 13) were observed in the immediate vicinity of the implanted nerve trunk.3. Following recovery from the paralysing action of botulinum toxin electrical stimulation of both the implanted and the original motor nerve evoked strong mechanical twitches in the gastrocnemius muscle.4. When the nerves were stimulated simultaneously little or no summation of tension occurred, indicating that presumably many of the muscle fibres with new end-plates also had functionally intact junctions from the original nerve. The presence of two end-plates in a muscle fibre was confirmed in a few experiments on single curarized fibres by intracellular recording of end-plate potentials on stimulation of each nerve.
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