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Auditory processing studied prospectively in two hemidecorticectomy patients
Dana Boatman1, Eileen P Vining, John Freeman
1Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA. dboatma@jhmi.edu
Journal of Child Neurology
|May 7, 2003
Summary
Auditory processing in children with Rasmussen's syndrome shows that while speech recognition is intact in quiet, it is impaired in noise after hemidecorticectomy. Both hemispheres are crucial for processing speech in noisy environments.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Speech Processing
Background:
- Rasmussen's syndrome is a rare neurological disorder characterized by progressive inflammation of one cerebral hemisphere.
- Hemidecorticectomy, a surgical procedure involving the removal or disconnection of one cerebral hemisphere, is a treatment for severe, intractable epilepsy associated with Rasmussen's syndrome.
- Understanding the impact of hemidecorticectomy on auditory processing is crucial for assessing functional recovery and cognitive rehabilitation.
Observation:
- Two pediatric patients (ages 10-11) with Rasmussen's syndrome underwent prospective auditory processing evaluation before and one year after hemidecorticectomy.
- Auditory word recognition was tested under four conditions: quiet, noise, acoustic filtering, and dichotic listening.
- Recognition of environmental sounds and discrimination of tones and syllables were also assessed.
Findings:
- Presurgical testing revealed normal auditory processing of speech and nonspeech sounds in both patients across all conditions.
- One year post-surgery, both patients exhibited intact recognition of words and environmental sounds in quiet.
- However, both patients showed impaired word recognition in noise. The patient with left hemidecorticectomy also had difficulty with low-pass filtered words, suggesting hemispheric specialization in auditory processing.
Implications:
- The findings suggest that either cerebral hemisphere can manage basic auditory processing of speech and nonspeech sounds in quiet environments.
- Processing speech in background noise appears to require the involvement of both hemispheres.
- Hemispheric roles in processing speech in noise may differ, with the left hemisphere potentially compensating for phonological deficits and the right hemisphere for attentional demands.