phasia is a language disorder but it can be a
hearing disorder too. It’s not that survivors
with aphasia can’t hear; they have difficulty
processing what they hear. It’s called auditory
overload (AO). We talked to Mary Purdy,
State University in New Haven, about this condition.
“Simplistically, AO is just too much info coming in at
once for the brain to process,” Purdy said. “It doesn’t even
have to be language, it can just be noise.” There are a lot of
auditory processing problems that a person with aphasia may
have. For example, individuals with a more mild aphasia may
have problems with people speaking too fast. For others, the
challenge may be background noise. Still others may have
difficulty holding onto a lot of information at one time.
AO is not hearing loss or increased sensitivity to sound. If a
survivor’s hearing were tested, it would be the same as before
the stroke. Hearing acuity is related to the ear and auditory
nerve. “When we’re talking about AO, it’s about once that
sound gets to the brain, what does it do with it?” Purdy said.
“In AO, the sound is getting to the brain but the brain is not
managing it well.”
There are several possible symptoms of AO:
• Inability to concentrate on a task or speaker.
• Becoming fidgety.
• Becoming impulsive and doing things quickly.
• Persisting on a task, or doing something over and over.
• Becoming distracted by any stimulation such as lights,
movement of others or objects in a room.
As with many post-stroke deficits, fatigue plays a role in AO.
When survivors get tired, their AO gets worse. But AO can also
be the cause of fatigue.
“This is not muscle fatigue, but more brain fatigue because
the brain has to work so hard at something that used to be
automatic,” Purdy said. “Once the system fatigues, it begins to
be much more inefficient. So the AO is going to happen more
quickly and the person is not going to be able to compensate
for it quite as well.”
Survivors with AO may become more isolated because
they are reluctant to go into challenging social environments
By Jon Caswell
UNDERSTANDING AND COMPENSATING
FOR AUDITORY OVERLOAD