Broca’s Aphasia vs. Aphemia

Aphasia is a disorder of speech an language caused by a strategic brain lesion.

Broca’s aphasia is a non-fluent type of aphasia with preserved comprehension caused by a lesion in the dominant (usually left) frontal lobe.

Broca’s affects both speech and writing. Because comprehension is spared, patients can monitor their own speech and become frustrated.

Affected patients will often find some alternate means of communication, other than speaking or writing, like Breaking Bad’s Hector Salamanca:

Aphemia is similar to Broca’s aphasia, but is caused by smaller lesions such that affected patients cannot speak but can still communicate with writing:

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Aphemia

Foreign Accent Syndrome – Their “Problem” or Yours?

FAS3

Foreign accent syndrome (FAS) is a rare condition which causes affected patients to suddenly speak their native language in a foreign accent.

Cases of FAS were reported as early as 1900.  However, one of the best known historical cases is “Astrid L”, a Norwegian woman who suffered a traumatic brain injury from shrapnel during a WW2 air raid in 1941.  She survived, but found herself mispronouncing vowels in such a way that she seemed to have a German accent, leading to social isolation and stigmatization for the remainder of the war.

Since then, there have been about another 60 FAS cases reported in the literature and media, mostly in patients who have suffered acute neurologic events such as strokes, multiple sclerosis and head injury.

Unlike most neurologic syndromes, FAS has not been localized to a lesion in a particular brain area.

The only thing that can be said is that most affected patients have lesions affecting the dominant hemisphere in or around known language areas.

FLS

Brain imaging studies from a FAS patient: The MRI (left) shows enlargement of the Sylvian fissure from atrophy of the left temporal lobe. The PET scan (right) shows focal hypometabolism in the left temporal lobe.

Many affected patients were initially mute, then developed FAS as they recovered from a non-fluent aphasia:

There are also some cases of FAS that have developed after minor neurologic events, or even without any clearly identifiable neurological cause at all.  Some of these patients have had normal brain imaging, suggesting that the problem can be functional or psychogenic.

This is all further complicated by the fact that different listeners can perceive different accents in a single speaker.

The video clip is a patent with FAS syndrome after brain injury from hemiplegic migraine.  She is said to have a Chinese accent.  Does it sound Chinese or just slurred to you?

The table below is from a FAS case report, where the affected patient’s “foreign accent” was obviously described very differently by observers.

FAS2

This suggests that FAS may not be a true syndrome after all, but simply a listener-bound epiphenomenon.

What does this mean?

Well, we have already explained that most FAS patients have some kind of speech or language problem that changed how they speak.  That explains the association with lesions in the dominant hemisphere.   However the “foreign accent” may actually just something perceived by the listener – the variability of perceived accents is explained by the fact that listeners have different experiences with languages other than their own.

In other words FAS may not be a true syndrome, but simply an epiphenomenon that exists only in the ears of the beholder.

Magnetic Brain Stimulation Might Help Stroke Rehab?

Repetitive transcranial magnetic stimulation (rTMS) of the brain has been used to treat a variety of neurologic and psychiatric disorders including depression and dytonia.

A new study published this week suggests that it might also help speed recovery of speech and language in stroke survivors.  The  study included 24 stroke survivors with aphasia. Thirteen of them received transcranial magnetic stimulation (TMS) for 20 minutes every day for 10 days followed by speech therapy.  The remaining 11 received a “sham” brain stimulation.

Patients in the TMS group showed three times greater improvement than those in the sham stimulation group.

Find out more here.

Epilepsy surgery and functional MRI

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Epilepsy surgery is an option for patients with intractable partial onset seizures that are not controlled by oral medications.  Epilepsy monitoring is used to localize the seizure focus, often a lesion or abnormal area of brain located in the temporal lobe.  That part of the brain is then carefully removed to prevent future seizures:

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A patient with a brain abnormality in the R temporal lobe (top) undergoes brain surgery to remove that area of brain and prevent future seizures.

Epilepsy surgery is very effective and yet still underutilized for treating seizures.

Left temporal lobe resections are more risky that right-sided cases, because the left hemisphere controls language functions in most (even left handed) patients.  Surgeons have to be very careful planning seizure surgery on the left side to be sure that they do not damage brain critical for speech and language and leave the patient with aphasia.

That’s where functional magnetic resonance imaging (fMRI) comes in.  fMRI goes beyond the conventional imaging of brain structure, and can actually localize regional brain functions by detecting changes in regional blood flow in response actual or imagined activity.

fMRI is increasingly being used to evaluate candidates for epilepsy surgery by identifying important functional regions within the brain, including unpredictable patterns of functional reorganization, to prevent unexpected post-operative deficits.  Click here for a link to a paper with illustrative cases.

Dystextia, A new neurologic symptom for the new year

texting

Neurology is laden with complicated terminology and eponyms.  For example, the terms aphasia or dysphasia indicate difficulty with verbal communication, most often from acute stroke affecting the dominant hemisphere.  The term apraxia indicates a disorder of motor planning causing an inability to perform a certain specific motor tasks even though strength is otherwise normal.  Dystextia is a term that has recently been coined to indicate the inability to create a coherent text message.

In a recent publication, Harvard physicians Ravi Rao and Klein describe an evolving stroke in a young woman manifest by dystextia:  A healthy 25-year old right-handed pregnant woman at 11 weeks’ gestational age, was brought to the emergency department after sending her husband a series of confusing text messages regarding their baby’s due date:

H: So what’s the deal?
P: every where thinging days nighing
P: Some is where!
H: What the hell does that mean?
H: You’re not making any sense.
H: July 24, right?
P: J 30
H: July 30?
P: Yes
H: Oh ok. I’m worried about your confusing answers
P: But i think
H: Think what?
P: What i think with be fine

Her brain magnetic resonance imaging showed an acute stroke in the left insular cortex:
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Similar but transient problems texting caused by both aphasia and apraxia were previously reported as dystextia caused by complicated migraine by New Zealanders Whitfield and Jayathissa in their 2011 paper.

However, it was a 2006 paper published in the Irish medical journal by Catwood, King and Sreenam that first used the term dystextia, resulting from simple loss of left hand dexterity in a 40-year-old man with a right hemispheric stroke, which then slowly recovered over time:
Dystextia_May06

In sum, young adults are spending more time texting and tweeting than talking or performing other daily activities.  We now have a descriptive term for when they have a neurologic event or process that prevents them from doing this.  However, it’s important to recognize that dystextia is a symptom, not a diagnosis, and can be caused by a variety of neurologic problems including aphasia, apraxia or simple loss of dexterity.