[Hearing acuity in the elderly in Japan]

Hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannoma

OBJECTIVE

To retrospectively examine the outcomes of hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannomas.

METHODS

Twenty-five patients with 26 vestibular schwannomas were treated with hypofractionated stereotactic radiation therapy using a CyberKnife. The vestibular schwannomas of 5 patients were associated with type II neurofibromatosis. The median follow-up time was 80 months (range: 6-167); the median planning target volume was 2.6 cm(3) (0.3-15.4); and the median prescribed dose (≥D90) was 21 Gy in three fractions (18-25 Gy in three to five fractions). Progression was defined as ≥2 mm 3-dimensional post-treatment tumor enlargement excluding transient expansion. Progression or any death was counted as an event in progression-free survival rates, whereas only progression was counted in progression-free rates.

RESULTS

The 7-year progression-free survival and progression-free rates were 78 and 95%, respectively. Late adverse events (≥3 months) with grades based on Common Terminology Criteria for Adverse Events, v4.03 were observed in 6 patients: Grade 3 hydrocephalus in one patient, Grade 2 facial nerve disorders in two and Grade 1-2 tinnitus in three. In total, 12 out of 25 patients maintained pure tone averages ≤50 dB before hypofractionated stereotactic radiation therapy, and 6 of these 12 patients (50%) maintained pure tone averages at this level at the final audiometric follow-up after hypofractionated stereotactic radiation therapy. However, gradient deterioration of pure tone average was observed in 11 of these 12 patients. The mean pure tone averages before hypofractionated stereotactic radiation therapy and at the final follow-up for the aforementioned 12 patients were 29.8 and 57.1 dB, respectively.

CONCLUSIONS

Treating vestibular schwannomas with hypofractionated stereotactic radiation therapy in three to five fractions may prevent tumor progression with tolerable toxicity. However, gradient deterioration of pure tone average was observed.

Comparisons of acoustic function in SCA31 and other forms of ataxias

OBJECTIVE

To investigate whether acoustic impairment can be one of the characteristic extracerebellar symptoms in sporadic and hereditary ataxias including spinocerebellar ataxia type 31 (SCA31).

METHODS

We investigated genotypes of dominant ataxia families, and determined a frequency of each form in our cohort of 154 families. Acoustic function in the groups of various forms of ataxia with multiple system atrophy of cerebellar predominance (MSA-C), cortical cerebellar atrophy (CCA), and hereditary ataxias including SCA31 was evaluated by using audiogram and brainstem auditory evoked potentials (BAEPs).

RESULTS

Genetic analysis of dominant ataxia families revealed that a frequency of SCA31 in our cohort was fewer than that reported from other areas of Japan, indicating that SCA31 is not widely distributed throughout Japan. Results of audiogram showed no significant difference of hearing levels among ataxic groups, and those of BAEPs did not support inner ear dysfunction in SCA31 in which hearing loss had initially been suggested as one of its characteristic symptoms.

CONCLUSION

This study suggests that acoustic impairment is neither specific to SCA31, MSA-C and CCA nor useful in making a differential diagnosis among them.

[Hearing examination program status in those aged 65 to 74--Knazawa hearing examination program findings]

The Kanazawa Otolaryngological Association has conducted a biennial hearing examination program for the Kanazawa City government since 2000 targeting persons aged 65 to 74 years. Studying results for 15,589 persons seen from 2000 to 2005 including 3247 undergoing more than one annual examination, we found results to be generally similar to those reported thus far. Of subjects, diagnosed with hearing loss, 16.4% were at 35dB or more. Almost 80% ranged from 35 to 50 dB. Aging was the most common cause of hearing impairment, followed by chronic otitis media at 5-8% and obstruction of the auditory tube (or secretory otitis media) at 3-5%. Of examinees with hearing impairment, 6-7% required treatment. High-frequency hearing loss (presbycusis) accounted for 40.0% of those 65-66 years old and 66.8% of those 73-74 years old. Among the 3247 persons undergoing more than one annual examination (mean followup: 6 years), those with obviously impaired hearing accounted for 2.1% with high-frequency hearing loss and 10.5% with no high-frequency hearing loss. Over 70% of those advised to use hearing aids were reluctant to do so. More work is thus needed with hearing-aid manufacturers to make devices more attractive to wear and use if we are to achieve the goals of the hearing examination program. Although we would like to continue the program by underlining the importance of hearing ability to administrative offices and local medical associations, there are limits on what local communities alone can do.