None of us can stand perfectly still. No matter how hard we try, our bodies constantly make small adjustments, causing us to sway slightly as we stand. A new study finds that people with bipolar disorder tend to sway more than those who are unaffected, which may lead to new ways to treat and diagnose the illness.

When psychologists diagnose bipolar disorder, they typically look for mood swings between agitated mania and bleak depression. Previous studies have linked bipolar disorder to abnormalities in the cerebellum and basal ganglia, regions of the brain that are also important for motor control. This connection led Indiana University psychologist Amanda Bolbecker and her colleagues to hypothesize that people with bipolar disorder might also have problems with motor skills.

To test their idea, Bolbecker’s team had 16 people with bipolar disorder and 16 age-matched healthy control subjects stand on a device called a force platform. The platform is similar in ap­pearance to a bathroom scale, but instead of measuring weight it calculates the pressure from different parts of the feet, which indicates how the body is swaying.

In every trial—with their eyes open or closed and with their feet different widths apart—the people with bipolar disorder wobbled more than the healthy subjects, indicating problems with motor control. The patients had the most trouble with their eyes closed, which suggests that the bipolar brain has difficulty integrating sensorimotor information, those inputs from the body and senses that assist the brain in maintaining balance and body position.

Bolbecker points out that the cerebellum, located at the base of the brain, helps to regulate movement and is also involved in emotional reactions, such as fear and pleasure. In addition, the cerebellum connects to other parts of the brain linked to cognition, mood regulation and impulse control, three areas in which patients with bipolar disorder often have difficulties. If the cerebellum is damaged at the cellular level, it may create problems with both mood and motor control.

This article was originally published with the title Motions Unmask Moods.

5 Comments

1. 1. Joetheplumber 06:01 AM 12/17/11

   I wonder to what extent this finding could be explained with the subjectivity of diagnosing something like Bipolar Disorder in the absence of objectively verifiable evidence (markers) for the disorder.
   
   The study group is people diagnosed with bipolar disorder vs. "normal" people. This naturally begs the questions what a group "diagnosed with bipolar disorder" means. More specifically, who gets diagnosed with bipolar disorder? More likely that not, not everyone with the biological basis of the disorder get diagnosed. Assuming there are threshold cases, and cases of differing severity, what would influence someone with bipolar characteristics to become diagnosed, and what characteristics would cause the disorder to remain hidden?
   
   Taking this perspective, and keeping in mind the fact that modern psychiatry is far from a standardized, objective science, ultimately being influenced as much by (heuristic) judgement calls and subjective evaluations as definite empirical markers, I hardly would accept this evidence as proof of bipolar disorder involving problems in motor control vs. "a diagnosis of bipolar disorder involves problems in motor control."
   
   To me, it seems more intuitive to explain the differences in "bipolar" vs. "normal" groups as a result of bias in diagnosing bipolar disorder. People who have blatant and statistically significant problems with maintaining balance might be considered more "reckless" or "manic" in a psychiatric evaluation than the "normal" populace.
   
   This study (falsely) implies that the following is true:
   Bipolar disorder is associated with poor motor control.
   
   This being what the studying is really testing:
   A diagnosis of Bipolar Disorder is associated with poor motor control.
   
   It may seem like an insignificant nuance, but in the long run, these kinds of nuance are required for a holistic understanding of causation vs. correlation in science today, and ultimately and an objective evaluation of scientific evidence. Neglecting the elephant in the room- that is, the subjectivity with which we diagnose most psychiatric conditions today- and treating these subjectively-determined groups as true, objective representations of the disorder in question could result in a lot of interesting sociological research, but it shouldn't be automatically regarded as "science" in my humble opinion.

   Reply | Report Abuse | Link to this

2. 2. jgrosay 04:37 PM 12/19/11

   When there was no efficacious therapy available for psychosis and other mental disorders, psychiatrists past their times trying to find the underlying rationale of delusions and hallucinations of patients, and speculating for hours and days about its mechanisms. When the armamentarium of drug and other therapies grew, papers moved to the side of such peculiar things as "minor neurologic signs" and all that stuff. Psychoanalysis, once widespread in some environments, saying "This patient has a pre-genital stuck" and similar things was a way for a professional to evade the legal and malpractice issues of emitting a prognosis, or defining a dangerous patient. Freud's work has more a forensic side above all others. It's good describing the lesions and how they were produced, but this supposedly doesn't heal. In many mental disorders, background issues such as a sufficient self-steem, a trait highly dependent on education and on interactions with others, and such apparently fool things such as a good quality of sleep may be determinant in the aparition and severity of some disorders included in DSM-V and other texts, and this issues are easy and cheap to address.

   Reply | Report Abuse | Link to this

3. 3. brynnscott 07:06 PM 12/19/11

   Interesting. As a person who is bi-polar type II and who cannot get past "amateur level" on any Wii fit balance game, I find this intriguing as a direction for further research. The Wii fit remark is partially tongue in cheek, but I have observed that I apparently have to work harder than most at certain Yoga stances or things of this nature. That does not mean I cannot ride a bike or roller skate (although I have more difficulty with ice skating and roller blading and when I tried one of those balance boards, well, let's just say it was embarrassing), I just need to be careful not to "over-correct."

   Reply | Report Abuse | Link to this

4. 4. ntn152207 10:17 AM 12/20/11

   I have seen many bi-polar human videos in youtube as they all have different characteristics. The science behind this is really explorable.

   Reply | Report Abuse | Link to this

5. 5. bpnowgirl 09:35 AM 12/27/11

   Were the bipolar subjects on meds? there are side-effects that can mimic the findings - dizziness alone is a side effect that could skew the results. I am sure the study designers must have taken this into account and solved for it, but I would like to know how. And if they didn't this is a profoundly flawed study.

   Reply | Report Abuse | Link to this