Strokes - (Jul/19/2006 )

Hi there

The other day in our lecture we were told that on the left cerebral hemisphere that the language areas eg: Broca's speech area and Wernicke's area and that if a left-handed and right-handed person were to suffer a stroke then the right-handed person would be more affected...however I can not remember the reason why could someone please enlighten me??? Does it have something to do that left-handed peoples actions are controled by the right handed sided of the body or something like that?....Also if both hemispheres are the same then what does the right cerbral hemisphere containing Broca's speech area etc do???

Thanks heaps
biology_06er

Some functions such as speech are assigned to certain areas in the brain which is located on one of the hemispheres. One would have a single Broca's area and not on both sides.

Regarding stroke, it depends on the area affected by stroke which determines the extent of disability and not on the fact that a person is right or left handed.

Ofcourse, if a right handed person with a stroke on the left hand side will suffer more than a left handed person with the same lesion site bcoz the one side of the brain controls the oppposite side of the body.

Hi

Thanks for that...so functions such as speech area are on different hemispheres for different people?

..........and say for example my broca's speech area is on my right hemisphere what exactly is on my left hemisphere in that exact same spot?

Thanks
biology_06er

regions of the brain are same for everyone - eg., broca's speech area is always in the left hemisphere. this is not the only area in the brain that involves speech, but because a right-handed person typically utilizes their left hemisphere more than a left-handed person, they are more dependent on it, and a stroke in the left hemisphere would be more detrimental, relatively speaking.

ohh ok cool...i get it now!...um but is it still possible to answer the other question....if broca's speech area is on the left hemisphere what is on the right hemisphere in that exact same spot?

Thanks
biology_06er

I dont know what is the function of the exact same region on the right hemisphere.

Not all regions of the brain have clear designatedd functions. They have vague functions. There r many associated regions which help regions with designated function. I would guess some sort of associated region.

Hi there

Thanks for that

biology_06er

Dear biology_06er,

Language shows hemispheric specialization, i.e. each hemisphere performs slightly different functions. ~95-99% of right-handed people have their language processes lateralized to the left hemisphere. For left-handers, ~70% have language localized to the left hemisphere, 15% have bilateral representation, and 15% have language localized to the right hemisphere. So, with a large left hemisphere stroke, virtually all righties will be aphasic, whereas 15% of lefties will have intact language and 15% will have incomplete loss of language functions... note that I said language, meaning symbolic communication- ability to communicate, understand, read, write etc. Speech refers to the ability to vocalize, and has its own localization. Before epilepsy surgery, a Wada test can be done to confirm language dominance; sodium amytal, an anesthetic, is injected into a single carotid artery; the drug will affect that hemisphere first, and the (awake) patient will be unable to speak or understand if that is the dominant hemisphere.

The regions corresponding to Broca's and Wernicke's areas in the right hemisphere (assuming left language dominance) control prosody- the production and understanding of emotional meaning in speech and gesture. For example, if we were talking in person and I said "Great!" you could tell from my intonation whether I was being sarcastic or pleased...