Objective: To describe methods of assessing cochlear implant candidacy in p
atients with potentially significant peripheral and central nervous system
(CNS) degeneration. Study Design: A patient with a degenerative CNS disease
(MELAS syndrome) undergoing evaluation for cochlear implantation is descri
bed.
Setting: This study took place at a tertiary care center.
Patient: A patient with mitochondrial encephalopathy, lactic acidosis, and
stroke-like episodes (MELAS) who had cortical blindness and profound sensor
ineural hearing loss was evaluated and rehabilitated with cochlear implanta
tion.
Interventions: Pure-tone audiogram, behavioral responses to promontory stim
ulation electrical auditory brainstem response, and electrically evoked mid
dle-latency responses (MLRs) were used to assess eighth nerve, auditory bra
instem, and cortical auditory pathways. Cochlear implantation with Cochlear
Corporation mini 22 implant was performed.
Results: Repeatable electrically evoked MLRs and behavioral responses to pr
omontory stimulation documented the presence of auditory cortical responses
. Successful implantation resulted in open set speech recognition and commu
nication using the auditory/oral mode.
Conclusion: This report describes successful implantation in a patient with
MELAS syndrome and demonstrates the ability to preoperatively confirm the
integrity of brainstem and cortical auditory pathways despite significant C
NS degeneration.