Language is an essential part of our lives that we often take for granted.
With it, we can communicate our thoughts and feelings,
lose ourselves in novels,
send text messages,
and greet friends.
It's hard to imagine being unable to turn thoughts into words.
But if the delicate web of language networks in your brain
became disrupted by stroke, illness, or trauma,
you could find yourself truly at a loss for words.
This disorder, called aphasia, can impair all aspects of communication.
People who have aphasia remain as intelligent as ever.
They know what they want to say,
but can't always get their words to come out correctly.
They may unintentionally use substitutions called paraphasias,
switching related words, like saying "dog" for "cat,"
or words that sound similar, such as "house" for "horse."
Sometimes, their words may even be unrecognizable.
There are several types of aphasia grouped into two categories:
fluent, or receptive, aphasia
and non-fluent, or expressive, aphasia.
People with fluent aphasia may have normal vocal inflection
but use words that lack meaning.
They have difficulty comprehending the speech of others
and are frequently unable to recognize their own speech errors.
People with non-fluent aphasia, on the other hand,
may have good comprehension
but will experience long hesitations between words and make grammatical errors.
We all have that tip-of-the-tongue feeling from time to time
when we can't think of a word,
but having aphasia can make it hard to name simple, everyday objects.
Even reading and writing can be difficult and frustrating.
So how does this language loss happen?
The human brain has two hemispheres.
In most people, the left hemisphere governs language.
We know this because in 1861,
the physician Paul Broca studied a patient
who lost the ability to use all but a single word, "tan."
During a postmortem study of that patient's brain,
Broca discovered a large lesion in the left hemisphere
now known as Broca's area.
Scientists today believe that Broca's area is responsible in part for naming objects
and coordinating the muscles involved in speech.
Behind Broca's area is Wernicke's area near the auditory cortex.
That's where the brain attaches meaning to speech sounds.
Damage to Wernicke's area impairs the brain's ability to comprehend language.
Aphasia is caused by injury to one or both of these specialized language areas.
Fortunately, there are other areas of the brain
which support these language centers
and can assist with communication.
Even brain areas that control movement are connected to language.
FMRI studies found that when we hear action words, like "run" or "dance,"
parts of the brain responsible for movement light up
as if the body was actually running or dancing.
Our other hemisphere contributes to language, too,
enhancing the rhythm and intonation of our speech.
These non-language areas sometimes assist people with aphasia
when communication is difficult.
So how common is aphasia?
Approximately 1 million people in the U.S. alone have it,
with an estimated 80,000 new cases per year.
About one-third of stroke survivors suffer from aphasia
making it more prevalent than Parkinson's disease
or multiple sclerosis,
yet less widely known.
There is one rare form of aphasia called primary progressive aphasia, or PPA,
which is not caused by stroke or brain injury,
but is actually a form of dementia
in which language loss is the first symptom.
The goal in treating PPA is to maintain language function for as long as possible
before other symptoms of dementia eventually occur.
However, when aphasia is acquired from a stroke or brain trauma,
language improvement may be achieved through speech therapy.
Our brain's ability to repair itself, known as brain plasticity,
permits areas surrounding a brain lesion
to take over some functions during the recovery process.
Scientists have been conducting experiments using new forms of technology,
which they believe may encourage brain plasticity in people with aphasia.
Meanwhile, many people with aphasia remain isolated,
afraid that others won't understand them or give them extra time to speak.
By offering them the time and flexibility to communicate in whatever way they can,
you can help open the door to language again,
moving beyond the limitations of aphasia.