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The Sleepwalking Defense

Evil Eye asks the following question in the forums:

Is sleepwalking/talking/eating etc… related to Dreaming or completely a seperate event?

Here’s why I asked….

link to story

ORANGE COUNTY, Fla. (WOFL FOX 35, Orlando) — Justin Cox, whose sleepwalking as a defense against child molestation charges was found not guilty on all counts Thursday afternoon.

The jury took about three hours to return the verdict.

Cox had taken the stand in his own defense Wednesday and told the jury that he was sleepwalking when the incident occurred.

Sleepwalking is an interesting neurological phenomenon. In order to understand it you need a little background on sleep. Sleep is divided into two categories: REM and non-REM (NREM) – REM stands for “rapid eye movement” which is the hallmark feature of this stage of sleep. NREM sleep is divided into four stages, I-IV, which are characterized by progressively deeper sleep and defined by progressively slower rhythms on EEG.

Sleep has a typical “architecture” characterized by sleep cycles we go through throughout a night of sleeping. A normal sleep architecture includes cycles of progressing from stage I to stage IV NREM sleep followed by a period of REM sleep (which is when we dream), and then the cycle repeats itself. In the early part of sleep these cycles tend to be longer with long periods of stage III and IV NREM sleep (called deep sleep and also slow wave sleep because of the slow rhythms, <4 hz, on EEG) and short periods of REM dreaming sleep. As the night progresses we tend to have shorter overall cycles and longer REM periods. We do most of our dreaming in the hours prior to waking up, and we have most of our deep sleep in the first two sleep cycles.

Sleepwalking (also called somnambulism) is one of the parasomnias – disorders of the normal sleep architecture. They generally are cause by a problem with transitioning from one sleep stage to another, like getting stuck while shifting gears. In the different stages of sleep different brain nuclei in the pons (part of the primitive brain stem) that regulate sleep will be active or inactive. These various patterns of activity in the pons are what determine overall brain activity and sleep stage. Many parasomnias are caused by abnormalities in shifting from one pattern of neuronal activity to another. This may cause the fusion of features from different sleep-wake states.

Sleepwalking tends to occur early in sleep, in the first two sleep cycles and they almost always occur out of NREM sleep – so they do not occur while dreaming. In fact they tend to occur during deep or slow wave sleep. If one is awakened from deep sleep they will usually be in a confusional state for a time – up to 30 minutes. It is difficult for the brain to rouse itself from this deep sleep state (a phenomenon called sleep inertia). Sleepwalking typically includes this confusional state. It also includes partial or complete amnesia for the event – people usually do not remember the sleep walking event, unless they are awakened from it, rather than being put back to bed.

With this deep confusion state there are feature of dreaming, specifically hallucinations and imagined realities. However, during REM dreaming sleep a nucleus in the pons paralyzes our muscles from the neck down – so that we do not act out our dreams. This nucleus is not active during sleepwalking, so the sleepwalker is able to physically act out their confused imaginings.

Sleepwalking tends to occur in children, and most children outgrow it – it is therefore considered to be a symptom of an immature nervous system. But rarely sleepwalking can persist into adulthood.

The question at hand is whether or not people can commit purposeful and complex actions while sleepwalking. Mostly, sleepwalkers just roam about aimlessly, with their eyes open. They are able to see and interact with their environment but are confused and either do not respond at all to questioning or may give a nonsensical rambling response. They are glassy-eyed and to not attend directly to other individuals. Sleepwalkers can engage in simple automatic behavior, like getting dressed, but it is currently controversial whether or not they can perform more directed behavior, like assaulting someone.

For example, the SleepChannel has this to say:

Currently, there is nonspecific medical evidence that suggests that there may be psychiatric issues involved in sleepwalking and that the actions of sleepwalkers in certain cases may not be autonomous and need to be reevaluated.

For example, in Britain, a man actually killed someone while sleepwalking. The issue is whether or not to acquit the defendant on the basis of autonomic actions or to find him insane and, therefore, release him to treatment for mental illness. Subsequently, there is controversy surrounding an individual’s right to plead insanity in cases like this, which complicates our perspective of agency in sleepwalking behavior. Sleepwalking is not currently defined or treated as a mental illness.

Future research may involve the development of a medical-legal definition of sleepwalking. Of course, cases like this are rare, but the media coverage of it is greatly responsible for public recognition of sleepwalking.

I also found this (from the London Sleep Center):

Somnambulism or sleepwalking is a viable defence on the basis of automatism. The behaviours that occur during sleepwalking can be highly complex and include sexual behaviour of all types. Somnambulistic sexual behaviour (also called sexsomnia, sleep sex) is considered a variant of sleepwalking disorder as the overwhelming majority of people with Sexsomnia have a history of parasomnia and a family history of sleepwalking. Sexual behaviour during a sleep automatism can vary from explicit sexual vocalisations, to violent masturbation, to complex sexual acts including anal, oral and vaginal penetration. A recent case in England is reported where the defendant was acquitted on 3 charges of rape on the basis of automatism due to somnambulistic sexual behaviour.

To review – it seems to me that complex behavior during sleepwalking, like assault or rape, is rare but possible. However, this is based upon very few cases and remains somewhat controversial. An alternative interpretation is that such behavior is a mental illness masquerading as sleepwalking. Most discussions on the issue point to the need for further research.

With regard to this specific case, therefore, sleepwalking is a plausible defense – although the specific details would be important to forming an opinion. It seems that the prosecution’s alternative hypothesis is that Cox was simply drunk during the assault and is using sleepwalking as a convenient excuse. Since the sleepwalking defense has some plausibility and precedent, we will likely not get a definitive answer in this case.

8 comments to The Sleepwalking Defense

  • DLC

    Sorry, but I don’t buy the Sleepwalker Defense any more than I buy the Twinkie defense.
    It may work from time to time in court, but I just don’t see it. As someone who has experienced sleepwalking and currently lives with a sleep disorder, I have researched the matter more than the average person. The evidence in favor of complex actions or behaviors is just too slim for me at the present time. I am of course willing to modify my viewpoint if further evidence is forthcoming. One case that came to mind was that of Scott Falater.
    I include a link here for those unfamiliar with the case.
    http://query.nytimes.com/gst/fullpage.html?res=9504E3DF133AF935A15755C0A96F958260

    Oh, and I also doubt that most cases of Multiple Personality Disorder are indeed multiple personalities and not the whim of the patient or therapist. But that is another issue.

  • Havermayer

    In regards to the “twinkie defence” it’s a modern myth:

    “The expression derives from the 1979 trial of Dan White, a former San Francisco, California (U.S.) Supervisor who assassinated Mayor George Moscone and Supervisor Harvey Milk on November 27, 1978. At the trial, noted psychiatrist Martin Blinder testified that White had been depressed at the time of the crime, and pointed to several factors indicating White’s depression: He had quit his job, he shunned his wife, and become slovenly in appearance. Normally a fitness fanatic and health food advocate, White had also been consuming Twinkies and Coca-Cola. As an incidental note, Blinder mentioned theories that elements of diet could worsen existing mood swings.[2] Another psychiatrist, George Solomon, testified that White had “exploded” and was “sort of on automatic pilot” at the time of the killings.[3] The fact that White had killed Moscone and Milk was not challenged, but in part because of the testimony from Blinder and other psychiatrists, the defense successfully argued for a ruling of diminished capacity. White was thus judged incapable of the premeditation required for a murder conviction, and was convicted of voluntary manslaughter instead. The verdict was unpopular, leading to the White Night Riots.

    In stories covering the trial, satirist Paul Krassner had played up the angle of the Twinkie,[2] and he would later claim credit for coining the term “Twinkie defense”.[4] The day after the verdict, columnist Herb Caen wrote in the San Francisco Chronicle about the police support for White (a former policeman himself) and their “dislike of homosexuals” and mentioned “the Twinkie insanity defense” in passing.[2] News stories published after the trial, however, frequently reported the defense arguments inaccurately, claiming that the defense had presented junk food as the cause of White’s depression and/or diminished capacity, instead of symptomatic of and perhaps exacerbating an existing depression.[5]”

    http://en.wikipedia.org/wiki/Twinkie_defense

  • Can we still say “Twinkie Defense” when referring to that scenario or what?

  • DLC

    The point of calling it “The twinkie defense” is not that anyone tried to prove that eating twinkies makes you kill people, but that White’s entire defense should have been laughed out of court. Being something of a skeptic, I tend to look at any “diminished capacity” defense critically. Especially so when the facts of the crime indicate careful planning and execution.
    Finally, I used a famous (if tied to myth)example for dramatic purposes.

    (Note to blog admin: how about a preview function? )

  • How do we know that we dream during REM sleep? I’m sure there is some really cool way that I just can’t think of beyond waking people up during it and asking.

  • Hayleyh36

    Nath-
    I just finished a sleep study, not for sleepwalking, but they glue electrodes to different parts of your head, neck, face, legs etc. They can tell when you are in REM by the electrodes on your face which track eye movement. They can tell that you are dreaming by what the electrodes on your head are recording.

  • Hayleyh36-
    Neat.
    Do the recordings match what we do when we daydream, or when we think of things that the other stages don’t have? I get the REM part, but I’m not sure I get that we know we are actually dreaming at that specific stage as opposed to another stage of sleep.

  • shoe

    Unfortunately, I’ve had many more sleep studies than I care to count (there’s nothing like the smell of the electrode glue to usher one off to sleep!)

    In answer to Nath’s question… REM does seem to have a specific pattern, from what I’ve gathered from my test results. As far as daydreaming… I’m not sure that’s the same animal as “dreaming” anyway.

    A “nap test” (Multiple Sleep Latency Test, MSLT) is used to diagnose things like narcolepsy and differentiate it from idiopathic hypersomnia. For instance, a positive result for narcolepsy shows people entering REM sleep extremely quickly after falling asleep (and falling asleep extremely quickly as well). A person might fall asleep within 3 minutes and start dreaming within 5 minutes, and I guess most techs wake you up after 20 minutes.

    Most people take about 90 minutes to reach the REM stage. The interesting thing about the defense, is that during this REM state, most people lose muscle tone. They are not able to move. Sleep paralysis, if my understanding is correct, is something that occurs when your brain is still in REM, but you’re partially awake/conscious, and the atonia that comes with the REM state isn’t completely gone.

    But as Steve says, sleepwalking (IANAD, just seen an awful lot of em, sigh) is a parasomnia that usually falls outside of REM sleep, which explains the ability to move.

    There is a disorder that sounds more like it would fit this defense called REM Behavior Disorder (RBD). Essentially, the loss of muscle tone doesn’t kick in when you dream, and you act out your dreams physically. And for some reason, they’re never EVER dreams about picking flowers and patting bunnies in a serene setting. In this case, though… It’s a stretch, and I’d think if you had any chance of using it as a defense, they’d have used it. It can be confirmed with testing.

    RBD occurs mostly in older men (and has been associated with Parkinson’s, before any Parkinson’s symptoms really become obvious). That being said, I’m not older, nor am I a man, and they strongly suspect this is part of my problem.

    RBD has been seen in younger people of both sexes who either are narcoleptic, or use anti-depressants, or both (I’m guessing most are in the both camp, since anti-depressants keep cataplexy at bay, and many doctors LOVE to diagnose really tired people with depression before much testing is even done). It’s still extremely uncommon, though.

    And I can tell you, I have had some wild nights where I have woken up, stood up, and started whacking the crud out of my poor husband (who is someone/thing else in my dream)… and the motion and his saying, “What the %&#) are you doing?” has been enough to wake me up out of the dream.

    I imagine the poor kid molested probably did make noise, and fight. I know I would have woken up out of an RBD episode in this case, and from what I can tell, REM sleep is a lot deeper than the stages when the parasomnias take place.

    I fear someone pulled a fast one on the jury.

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