WEBVTT

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Language is an essential part of our lives
that we often take for granted.

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With it, we can communicate our thoughts
and feelings,

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lose ourselves in novels,

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send text messages,

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and greet friends.

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It's hard to imagine being unable
to turn thoughts into words.

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But if the delicate web of language
networks in your brain

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became disrupted by stroke,
illness, or trauma,

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you could find yourself truly
at a loss for words.

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This disorder, called aphasia,
can impair all aspects of communication.

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People who have aphasia remain
as intelligent as ever.

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They know what they want to say,

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but can't always get their words
to come out correctly.

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They may unintentionally use
substitutions called paraphasias,

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switching related words,
like saying "dog" for "cat,"

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or words that sound similar,
such as "house" for "horse."

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Sometimes, their words may even be
unrecognizable.

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There are several types of aphasia
grouped into two categories:

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fluent, or receptive, aphasia

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and non-fluent, or expressive, aphasia.

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People with fluent aphasia may have
normal vocal inflection

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but use words that lack meaning.

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They have difficulty comprehending
the speech of others

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and are frequently unable to recognize
their own speech errors.

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People with non-fluent aphasia,
on the other hand,

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may have good comprehension

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but will experience long hesitations
between words and make grammatical errors.

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We all have that tip-of-the-tongue feeling
from time to time

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when we can't think of a word,

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but having aphasia can make it hard
to name simple, everyday objects.

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Even reading and writing can be difficult
and frustrating.

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So how does this language loss happen?

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The human brain has two hemispheres.

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In most people, the left hemisphere
governs language.

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We know this because in 1861,

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the physician Paul Broca studied a patient

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who lost the ability to use all 
but a single word, "tan."

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During a postmortem study
of that patient's brain,

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Broca discovered a large lesion
in the left hemisphere

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now known as Broca's area.

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Scientists today believe that Broca's area
is responsible in part for naming objects

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and coordinating the muscles
involved in speech.

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Behind Broca's area is Wernicke's area
near the auditory cortex.

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That's where the brain attaches
meaning to speech sounds.

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Damage to Wernicke's area impairs the
brain's ability to comprehend language.

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Aphasia is caused by injury to one or
both of these specialized language areas.

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Fortunately, there are other areas
of the brain

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which support these language centers

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and can assist with communication.

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Even brain areas that control movement
are connected to language.

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FMRI studies found that when we hear
action words, like "run" or "dance,"

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parts of the brain responsible
for movement light up

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as if the body was actually running
or dancing.

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Our other hemisphere contributes
to language, too,

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enhancing the rhythm and intonation
of our speech.

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These non-language areas sometimes
assist people with aphasia

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when communication is difficult.

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So how common is aphasia?

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Approximately 1 million people
in the U.S. alone have it,

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with an estimated 80,000 new cases
per year.

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About one-third of stroke survivors
suffer from aphasia

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making it more prevalent 
than Parkinson's disease

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or multiple sclerosis,

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yet less widely known.

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There is one rare form of aphasia called
primary progressive aphasia, or PPA,

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which is not caused by stroke
or brain injury,

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but is actually a form of dementia

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in which language loss 
is the first symptom.

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The goal in treating PPA is to maintain
language function for as long as possible

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before other symptoms of dementia
eventually occur.

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However, when aphasia is acquired
from a stroke or brain trauma,

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language improvement may be achieved
through speech therapy.

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Our brain's ability to repair itself,
known as brain plasticity,

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permits areas surrounding
a brain lesion

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to take over some functions during
the recovery process.

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Scientists have been conducting
experiments using new forms of technology,

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which they believe may encourage brain
plasticity in people with aphasia.

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Meanwhile, many people with aphasia
remain isolated,

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afraid that others won't understand
them or give them extra time to speak.

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By offering them the time and flexibility
to communicate in whatever way they can,

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you can help open the door 
to language again,

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moving beyond the limitations of aphasia.