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siderable number have been tested and examined during the year
and the "failures" treated, with full restoration of hearing in
the majority of cases. As well, all children treated for otitis are
tested for "degree of deafness," at intervals, to check-up on their
progress. The Cowan Picture Frames are a valuable addition
to this Audiometer as they permit very young children, who do
not know the standard tests, to be accurately examined.
Pure Tone Audiometer.—During the past year the Education
Committee authorised the purchase of a Pure Tone Audiometer.
This is the most minutely accurate scientific apparatus devised for
the detection of deafness, both quantitative and qualitative. It
differs from the Gramophone Audiometer in the fact that it not
only tells the amount of the "Hearing Loss" but also, the nature
and situation of the defect, i.e., which frequencies (or pitch),
lower, middle or higher, are affected, and thus indicates the seat
of the lesion—middle ear, nerve, central origin, etc. The result
of the test is graphically shown on a special chart, known as an
Audiogram, and is a permanent record of the hearing at the time.
The Audiogram is of greatest value in diagnosis and treatment,
when intelligently interpreted, thus its functions are:—
(1) It shows whether a child has any hearing at all.
(2) It shows the pitch range of demonstrable hearing.
(3) It indicates the degree of loudness of sounds which will
reach his ear.
(4) It assists in classifying on a hearing basis, children with
defective hearing in special schools.
(5) It assists in coming to a decision as to which educational
environment a child should be placed in.
(6) It gives evidence of the type of hearing defect from which
a child is suffering.
(7) It shows the relative hearing by Air and Bone conduction.
(8) It gives an indication as to whether a child would receive
help from an amplifier.
(9) Where an amplifier would benefit, it indicates the type of
hearing aid which should be used and also the characteristics
in the "build-up" of the instrument which would
appear to be required.