Case Report
Differential Treatment Response of Auditory Hallucination in A Unilateral Hearing Impaired Patient: A Case Report
Ram D, Tharun Krishnan R, Najla E and Sathyanarayana Rao TS*
Department of Psychiatry, JSS University, Mysore, India
*Corresponding author: Sathyanarayana Rao, Department of Psychiatry, J.S.S Medical College and Hospital, J.S.S University, Mysore, India
Published: 13 Apr, 2017
Cite this article as: Ram D, Tharun Krishnan R,Najla E,
Sathyanarayana Rao TS. Differential
Treatment Response of Auditory
Hallucination in A Unilateral Hearing
Impaired Patient: A Case Report. Ann
Clin Case Rep. 2017; 2: 1331.
Abstract
Auditory hallucinations may present as a part of the diagnostic symptom profile in hearing impaired with schizophrenia and respond to antipsychotics. Though partial response is observed with inadequate dose of antipsychotics, there is no report that auditory hallucinations respond differently in a patient with a healthy and impaired ear. In this case report, we are reporting differential effect of antipsychotics on auditory hallucinations in a unilateral hearing impaired patient with schizophrenia. Possible underlying neurobiological mechanisms are discussed.
Keywords: Impaired hearing and schizophrenia; Differential effect to hearing; Antipsychotics and hearing impairment
Introduction
The prevalence of schizophrenia among hearing impaired is nearly equal to that of the general population [1]. Both bilateral and unilateral auditory hallucinations in hearing impaired are thought to predispose them to develop schizophrenia [2]. Auditory hallucinations in patients with normal hearing may inadequately respond to antipsychotic medication [3]. There is no report that hallucinations (due to psychiatric disorders) in patients with hearing impairment respond differently to antipsychotics. Similarly there is no report that auditory hallucinations respond to antipsychotics differently in a patient with healthy and impaired ear. Here we are reporting a case of differential response of auditory hallucination to antipsychotics in a unilateral hearing impaired patient with schizophrenia.
Case Presentation
Forty nine years old married male, educated upto class 10th, with a well adjusted premorbid
personality and without any family history of mental illness, presented with complaints of hearing
voices in both the ears that had suddenly started three months ago. He described that many male
voices would talk about him, comment about whatever he does, would often give him instructions
but he would never follow them. He was distressed because they would accuse him. He believed that
people were against him and wanted to harm him about which he would come to know through
these voices. So he started staying back at home and stopped going for work. There was no history
of other psychiatric disorders except for occasional alcohol use. The patient had a past history of a
fall under the influence of alcohol about two years back, when he had loss of consciousness lasting
for about fifteen minutes with right ear bleed. First aid was provided but brain injury was not ruled
out then (due to unavailable medical service). Since then the patient developed hearing impairment
in the right ear.
There is no history suggestive of other psychiatric disorders currently or in the past. On mental
status examination patient was anxious, preoccupied, and at times was found muttering to self. He
revealed delusions of persecution and reference as well as 2nd and 3rd person auditory hallucinations.
He scored 58 on Brief psychiatric rating scale (BPRS). Physical examination revealed sensorineural
hearing loss. ENT and audiological evaluation revealed moderately severe sensorineural hearing loss
in the right ear with Pure tone audiometry(PTA) -51.6dB, Speech recognition threshold (SRT)-60dB
and Speech identification scores(SIS)-90%. CT & MRI scan, neuropsychometric tests, and blood
investigation were within normal limits. A diagnosis of paranoid schizophrenia was considered
based on the International Classification of Diseases - 10th edition (ICD-10) [4]. There was no
evidence to suggest that the illness was caused by the head injury which had occured two years back.
After discussion with the patient, tab.risperidone 2 mg/day was started and increased to 6 mg/
day over 6 weeks. Patient had overall improvement of symptoms (BPRS =32), except for 2nd and 3rd person auditory hallucinations in the impaired ear (right ear). No
side effects were observed. Risperidone was further optimised to 9 mg
without much improvement but patient developed extrapyramidal
symptoms that improved with 4 mg of trihexyphenidyl in two
divided doses. Tab.aripiprazole 10 mg was added and patient ceased
to experience auditory hallucinations (BPRS =12) at the end of two
weeks. This antipsychotic differential response (on deaf and normal
ear) is scored as certain on WHO-UMC Causality Categories. Patient
was advised to use hearing aid regularly. On follow-up patient
maintained improvement.
Discussion
Although unilateral hallucinations have been reported in
persons with an impaired and healthy ear, this case report is unique
because of the differential response of auditory hallucinations in
impaired ear to risperidone. Studies revealed predominant temporal
lobe involvement in patient with schizophrenia who experience
auditory hallucinations. Neuroimaging studies found activation or
deactivation of parahippocampal gyrus, activation of left superior
temporal lobe (Broca's and Wernicke's areas) & auditory association
cortex and reduced activation of portions of the brain associated with
the monitoring of inner speech [5]. This patient had history of fall with
associated unconsciousness that led to right ear hearing impairment.
Though there was no objective evidence of temporal lobe damage in
this patient, it lies directly above the middle ear and traumatic injuries
may play a role in neuropathology of schizophrenia. Temporal
lobe epilepsy & pathology is reported to cause schizophrenia like
symptoms [6].
The perception of voices as objects in external space depends
on filtering by the outer ear [6]. There is a central role of the left
hemisphere in auditory imagery [7] and the left planum temporale
has a critical role in the perception of voices in external space. It is
speculated that imagery arises from activation of a neural substrate
shared with perceptual mechanisms, and provides evidence for a
right temporal-lobe specialization for this type of auditory imaginal
processing [8]. An advantage of the right ear (REA) in auditory
processing (especially for verbal content) has been firmly established
in decades of behavioral, electrophysiological and neuroimaging
research [9]. Hallucinations in impaired hearing is thought to be the
result of perceptual deficits, abnormal meta-representational abilities,
impaired monitoring of intended speech, discourse failure, disorder
of consciousness, misidentification of imagination, weakening of
memory storage processes and impairment of the ability to monitor
source of willed intentions to act [10]. In this patient with unilateral
hearing impairment, hallucinations were probably influenced
by combination of factors associated with oto-neurological
(sensorineural hearing loss) and neuropsychiatric disorders
(schizophrenia) that might have resulted in a differential response of
hallucinations to risperidone in impaired and non-impaired ear.
Though hearing loss is commonly associated with anxiety,
depression, impaired subjective well-being & social functioning, there
is a potential link between ear disease and schizophrenia particularly
paranoid delusions and auditory hallucinations, and the use of a
hearing aid can reduce psychotic symptoms in patients with deafness.
When hearing system is damaged, normal cortical neuronal pattern
of band-pass filters of different frequency ranges will be changed to
an increase in the bandwidth of the nerve fibers with an expected
noise amplification, loss of resolution, and poor specificity of cortical
reactions. Spontaneous activity of groups of neurons, which in the
absence of external sounds can create a pattern that resembles the one
evoked by sound. Thus hearing-impaired individuals could represent
the response of a hypersensitive auditory cortex chronically deprived
of sensory input [11]. This case highlights the need to keep in mind
the neurological deficits like sensory neural hearing deficits in any
patient while prescribing antipsychotics.
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