Diseases Of The Nose Throat And Ear

398 THE EAR

little morbidity or mortality. A suboccipital or combined approach is required
for the larger tumours.

The classic neurosurgical approach to the tumour is by way of an occipital
osteoplastic flap, with bilateral suboccipital craniectomy. In the early case
with a small tumour, complete removal can be achieved with no prospect
of regrowth, although sometimes the facial nerve must be sacrificed. In
advanced cases it is rarely possible to effect complete removal without undue
risk to neighbouring structures and consequently incomplete subtotal
removal is resorted to, with associated greater surgical risks and more severe
postoperative residual disabilities. Being relatively slow-growing the incidence
of further tumour growth after 9 years is only 20 per cent. A more common
sequel (40 per cent within 2 years) is chronic progressive hydrocephalus due
to adhesive arachnoiditis, provoked by proteinous transudate from residual
tumour tissue into the surrounding cerebrospinal fluid.

PSYCHOGENIC DEAFNESS

Deafness may be met with in hysteria:, it is not as a rule attended by tinnitus
or giddiness. The deafness may come on without obvious cause and is
subject to marked variations; it is sometimes transferred from one side to the
other. The results of hearing tests repeated on several occasions vary greatly
and this is a valuable diagnostic point. Further evidence of hysteria can
generally be found, such as the presence of areas of anaesthesia, or the loss
or impairment of smell or taste on the same side as the deafness. Sudden and
complete recovery of hearing clinches the diagnosis of hysterical deafness.

Cases of bilateral functional deafness have been met with as the result of
explosions. There is frequently an associated initial degree of organic deaf-
ness. The functional element, however, persists after the organic defect has
more or less recovered. Such cases are extremely difficult to assess. Deafness
may be accompanied by mutism. To differentiate between bilateral organic
and functional deafness, the study of the voice resonance is helpful; in total
deafness of organic origin, the patient's voice quickly acquires the intonation
characteristic of the deaf, while in functional lesions the voice remains
normal. It is important to examine the cochleo-auricular, -pupillary and
-palpebral reflexes', a shrill whistle, a motor horn or a bell with a spring
hammer is suddenly sounded behind the patient, who should look into the
distance to avoid fixation of the pupil. If the patient hears the sound, a
movement of the pinna may be noted, accompanied by contraction of the
pupil and winking. Where the deafness is absolute the reflex is absent; but in
partial deafness, whether organic or functional, it is usually present. If it is
present, but the patient says he can hear nothing, he is probably a malingerer;
but so long as he admits that he can hear something, the test does not help in
distinguishing between organic deafness, functional deafness and malingering.
When total deafness is not of organic origin, the vestibular reactions are, of
course, normal. An unexplained discrepancy between pure-tone and speech
audiograms arouses suspicion, especially when speech is better than pure-
tone reception.

Attention is an active process. It may be spontaneous, as in a child, or it
may be voluntary, i.e. due to training. In functional deafness both spontaneous
and voluntary attention are withdrawn. In the subconscious malingerer, the