# On brain waves and abortion - 25 weeks? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [November 3, 2008, 4:06am UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816 "2008-11-03T04:06:10Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [November 3, 2008, 4:06am UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/1 "2008-11-03T04:06:10Z")
Cecil addresses [when does human life begins](http://www.straightdope.com/columns/read/2817/when-does-human-life-begin) and states that a logical milestone for the beginning of personhood, “…is the beginning of measurable brain-wave activity, roughly 25 weeks after conception. After all, brain death is now commonly accepted as marking life’s end.” Ok, but poster [Ian Rey](http://boards.straightdope.com/sdmb/showpost.php?p=10354870&postcount=10) refers to studies indicating activity somewhere in the 17-27 week range. [Carl Sagan](http://www.2think.org/science_abortion.shtml) set the line later: > [@Carl Sagan](#): > > But large-scale linking up of neurons doesn’t begin until the 24th to 27th week of pregnancy–the sixth month. > > By placing harmless electrodes on a subject’s head, scientists can measure the electrical activity produced by the network of neurons inside the skull. Different kinds of mental activity show different kinds of brain waves. But brain waves with regular patterns typical of adult human brains do not appear in the fetus until about the **30th week of pregnancy** –near the beginning of the third trimester. Fetuses younger than this–however alive and active they may be–lack the necessary brain architecture. They cannot yet think. So what is it, 17 weeks, 25 or 30? That’s a pretty broad range after all, covering most of the 2nd trimester. I see from Ian Rey’s post that bilaterally synchronous EEGs only occur at 26 to 27 weeks. I lack sufficient background to evaluate that. ---
**Author:** ![geniios](https://avatars.discourse-cdn.com/v4/letter/g/9d8465/32.png) [@geniios](https://boards.straightdope.com/u/geniios)\ **Post date:** [November 6, 2008, 11:36pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/2 "2008-11-06T23:36:40Z")
I dunno I am sure I have met people with no discernable brain waves, who… no you must be right they couldn’t think either. So when an old person has dementia at some point they become abortable right? ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [November 7, 2008, 2:01pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/3 "2008-11-07T14:01:47Z")
> [@geniios](#): > > I dunno I am sure I have met people with no discernable brain waves, who.. no you must be right they couldn’t think either. > So when an old person has dementia at some point they become abortable right? 😕 Are you trying to suggest that someone with dementia does not have brain waves?? ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [November 7, 2008, 2:50pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/4 "2008-11-07T14:50:12Z")
> [@geniios](#): > > I dunno I am sure I have met people with no discernable brain waves, who.. no you must be right they couldn’t think either. > So when an old person has dementia at some point they become abortable right? :dubious: People with dementia still have brainwaves. Where did you get the idea they didn’t? What a bizarre concept. However, people who are brain dead may not (I’m not sure – maybe someone more knowledgeable can chime in). You’re right, brain dead people are “abortable” – that is, removed from life support. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [November 7, 2008, 8:57pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/5 "2008-11-07T20:57:38Z")
According to [How Stuff Works](http://health.howstuffworks.com/brain-death1.htm), the legal time of death is, “that time when a physician(s) has determined that the brain and the brain stem have irreversibly lost all neurological function.” There are a number of tests involved, but one method of confirming brain death involves the EEG. “The patient in the deepest coma will show some EEG electroactivity, while the brain-dead patient will not.” I am not a doctor, nor have I devoted study to this matter. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [November 7, 2008, 9:04pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/6 "2008-11-07T21:04:28Z")
> [@Measure\_for\_Measure](#): > > So what is it, 17 weeks, 25 or 30? That’s a pretty broad range after all, covering most of the 2nd trimester. I don’t have extra data to add to this, but I suspect Sagan’s answer contains a partial solution - he makes pains to distinguish that “brain waves with regular patterns typical of adult human brains” are happening around week 30. So I wouldn’t be surprised if there was EEG activity at week 17 but not resembling that of a normal, developed human. ---
**Author:** ![geniios](https://avatars.discourse-cdn.com/v4/letter/g/9d8465/32.png) [@geniios](https://boards.straightdope.com/u/geniios)\ **Post date:** [November 8, 2008, 12:05pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/7 "2008-11-08T12:05:08Z")
I said “at some point” you really should read more, so you would have comprehension skills and not have to ask such obvious questions. > [@Canadjun](#): > > 😕 Are you trying to suggest that someone with dementia does not have brain waves?? ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [November 8, 2008, 5:00pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/8 "2008-11-08T17:00:23Z")
> [@geniios](#): > > I said “at some point” you really should read more, so you would have comprehension skills and not have to ask such obvious questions. You said "I dunno I am sure I have met people with no discernable brain waves, who.. no you must be right they couldn’t think either. So when an old person has dementia at some point they become abortable right? " It sure sounds to me like you are saying that “at some point” an old person with dementia doesn’t have brainwaves. If that is not what you meant, the second sentence is a non-sequitur. ---
**Author:** ![flodnak](https://avatars.discourse-cdn.com/v4/letter/f/838e76/32.png) [@flodnak](https://boards.straightdope.com/u/flodnak)\ **Post date:** [November 8, 2008, 5:30pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/9 "2008-11-08T17:30:34Z")
> [@geniios](#): > > I said “at some point” you really should read more, so you would have comprehension skills and not have to ask such obvious questions. Ah, gratuitous insults. That’s rarely a good sign. An elderly person with dementia will continue to have brain wave activity as long as there is life in her body. It doesn’t matter if her disease is so advanced that she lacks thought or even self-awareness. Her brain waves won’t look like they did when she was healthy, but some sort of activity will continue until she dies. Even an anencephalic infant (born with most of the brain missing) will show brain wave activity. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [November 9, 2008, 2:27am UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/10 "2008-11-09T02:27:48Z")
Yes, the point at which any person is declared dead is the point at which they have no brain waves, according to the How Stuff Works link, though there are other metrics as well. Reading comprehension indeed. ---
**Author:** ![geniios](https://avatars.discourse-cdn.com/v4/letter/g/9d8465/32.png) [@geniios](https://boards.straightdope.com/u/geniios)\ **Post date:** [November 9, 2008, 5:29pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/11 "2008-11-09T17:29:48Z")
It sure sounds to me like you are saying that “at some point” an old person with dementia doesn’t have brainwaves. Exactly, I did say that. **Everyone** “at some point” doesn’t have brain waves. Don’t get your panties twisted. > [@Canadjun](#): > > You said "I dunno I am sure I have met people with no discernable brain waves, who.. no you must be right they couldn’t think either. > So when an old person has dementia at some point they become abortable right? " > > It sure sounds to me like you are saying that “at some point” an old person with dementia doesn’t have brainwaves. If that is not what you meant, the second sentence is a non-sequitur. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 9, 2008, 5:59pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/12 "2008-11-09T17:59:47Z")
Yes, but at the point where you don’t have brainwaves any more, you also don’t have dementia any more, since you don’t have _anything_ any more. Death is the one known surefire cure-all. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [November 9, 2008, 6:19pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/13 "2008-11-09T18:19:40Z")
> [@geniios](#): > > It sure sounds to me like you are saying that “at some point” an old person with dementia doesn’t have brainwaves. > Exactly, I did say that. **Everyone** “at some point” doesn’t have brain waves. Don’t get your panties twisted. Are you trying to suggest that **any** living person (with or without dementia) does not have brainwaves? If so, you don’t know what you are talking about. If not, then your comment about someone with dementia “at some point” being abortable doesn’t make very much sense, now does it? One doesn’t normally talk about aborting a dead person. ---
**Author:** ![geniios](https://avatars.discourse-cdn.com/v4/letter/g/9d8465/32.png) [@geniios](https://boards.straightdope.com/u/geniios)\ **Post date:** [November 9, 2008, 6:51pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/14 "2008-11-09T18:51:31Z")
Okay, I see, well you really should warn me when we enter normal conversation. It’s really hard to just know that on these boards. > [@Canadjun](#): > > Are you trying to suggest that **any** living person (with or without dementia) does not have brainwaves? If so, you don’t know what you are talking about. If not, then your comment about someone with dementia “at some point” being abortable doesn’t make very much sense, now does it? One doesn’t normally talk about aborting a dead person. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [November 9, 2008, 9:57pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/15 "2008-11-09T21:57:17Z")
Let me try to get the proper facts lined up. > [@geniios](#): > > I dunno I am sure I have met people with no discernable brain waves, who.. no you must be right they couldn’t think either. > So when an old person has dementia at some point they become abortable right? Just to be clear. No, when an old person has dementia, they still have brain waves. ## When somebody -anybody- no longer has brain waves, they are considered dead, as they no longer have brain function. Regarding the OP, I see from the [Mayo Clinic](http://www.mayoclinic.com/health/fetal-development/PR00114) that the third trimester begins in week 28. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 9, 2008, 11:52pm UTC](https://boards.straightdope.com/t/on-brain-waves-and-abortion-25-weeks/470816/16 "2008-11-09T23:52:50Z")
> [@](#): > > Okay, I see, well you really should warn me when we enter normal conversation. I wasn’t aware that we had ever left normal conversation.