Proposed Research on Developmental Language Disorders
Eileen Nicole Simon
Possible importance of the inferior colliculi in speech understanding
The inferior colliculus in the midbrain auditory pathway (Figure 1) may play a special
role in analysis of the acoustic features of speech. Since 1991, with the advent of
magnetic resonance imaging (MRI), eleven cases of deafness and auditory agnosia
have been reported, associated with selective (and bilateral) damage of the inferior
colliculi [1-10]. Loss of speech understanding was the primary problem in nine of these
cases [2, 4-10]. Figure 2 shows the damage in the inferior colliculi in the case of a man
who suffered closed-head injury in a skiing accident; impact from the free edge of the
cerebellar tentorium was thought to have caused this injury .
Figure 3 shows damage to the inferior colliculi found in experiments with newborn
monkeys subjected to asphyxia of 8 to 10 minutes duration [11, 12]. Damage of the
inferior colliculi in human infants has also been reported [13-21]; an example can be
seen in figure 4. Gilles (1963) suggested that ischemic damage of this type in the
inferior colliculi might be responsible for some childhood aphasic disorders .
Subjects and tests
The purpose of the research proposed here is to use functional MRI (fMRI) to investigate:
I. The hypothesis put forward by Gilles (1963) that impairment of function in the
inferior colliculi might underlie some developmental language disorders , or
II. Whether some developmental language disorders occur in the absence of any
measurable impairment of auditory function.
Posted: December 2005
Updated 1/8/06 to fix broken links