Monday, August 30, 2010
A 30-year-old woman waddles into a family clinic with a large belly and tender breasts. She says she can feel her baby moving inside of her. A doctor performs a pelvic exam and discovers that not only is there no baby, there's no uterus. Her medical records show she'd had a hysterectomy two years earlier.
This case presented itself to Paul Paulman, a professor and family practitioner at the University of Nebraska. It was his first encounter with a rare condition called pseudocyesis, or false pregnancy. "I showed the woman a scan of her abdomen and explained the facts," Paulman says, "and then I never saw her again. I don't know if she ever accepted the truth."
In pseudocyesis, the mind tricks the body, and vice versa. Doctors think it develops when a woman obsesses over pregnancy out of desire or fear. (Queen "Bloody" Mary I of England famously suffered false pregnancy under pressure to continue the royal line.) A woman may stop menstruating, or her stomach may become distended due to stress or constipation. But her brain interprets the signs as pregnancy, which triggers the pituitary gland to secrete hormones like prolactin to prepare the body to carry a child. She gains more weight around the midsection, and her breasts swell and might even lactate. Many false pregnancies end when the woman goes into labor and delivers nothing.
Pseudocyesis occurs in only 1 to 6 of every 22,000 pregnancies, and it can also happen to children, the elderly, and men. "I think the men are a little more emotionally ill," Paulman says. Doctors confront the patient with medical evidence and offer counseling. If that doesn't work, the patient could have an underlying psychotic illness.
Pseudocyesis has a sibling syndrome: "couvade," or sympathetic pregnancy, where men experience many of the symptoms of their wives' or daughters' pregnancies—weight gain, nausea, headache, irritability, backaches, abdominal pain. A study of 81 expectant fathers found that almost half of them gained weight in the third trimester. Sympathy abdominal pains during birth are even more common, Paulman says. "I guess we all want to be in touch with our feminine side."
Case Study: A Family Saved by a Phantom Delivery
• The Patient
A 36-year-old mother of four with a history of depression and hypomania.
• The Delivery
Upon hearing that her 19-year-old son's girlfriend was going into labor, she began to experience excruciating pain in her abdomen. She felt as though she were having contractions, and after an hour, she gave "a final push." Afterward, she was exhausted, relieved, and overjoyed.
• The Cause
The patient had been estranged from her son because she disapproved of his girlfriend and believed they were too young to have children. The phantom delivery may have been her way to include herself in the birth of her first grandchild.
• The Resolution
After "labor," the grandmother felt ready to embrace her son, his girlfriend, and their baby.
Tuesday, August 24, 2010
Brain wiring key to quick decisions: study
Australian Broadcasting Corporation
The ability to make quick decisions when they are needed depends on whether your brain connections are the neural equivalent of broadband or dial-up, an international study shows.
In a Proceedings of the National Academy of Sciences paper released online Tuesday, an international team shows flexibility in decision-making is dependent on structural features of the brain.
'As you get older, the bandwidth gets slower and slower.'— Scott Brown
Quick decisions tend to be error-prone while relatively slower contemplation tends to produce more accuracy, says one Australian research team member, Scott Brown, an associate professor at the University of Newcastle's cognition laboratory.
This trade-off between speed and accuracy means people need to be able to switch between the fast risky and slower cautious modes of decision-making, as required.
But, says Brown, little is known about the neurology underpinning this flexibility.
Broadband or dial-up?
In their study, Brown and colleagues, which included researchers from the United Kingdom, Germany and the Netherlands, examined what brain mechanisms underpin decision-making flexibility.
They found it was determined by the "purely physical measurement" of the thickness of the connections between the brain's cortex and the striatum of the basal ganglia.
He says the results are the equivalent of brain communication being reliant on a broadband connection or still using dial-up.
"The underlying finding that a purely physical measurement could predict behaviour is very surprising," he says.
Brown says the team has not determined what causes one person's connections to be thicker than another's.
"It could be that it is the 'use it or lose it'" phenomenon, he says.
However, in a paper still under review, Brown says, the team has also shown the connection thins with age.
"As you get older, the bandwidth gets slower and slower," he says.
MRI scans measure fibre thickness
For the study, participants were placed in an MRI scanner and the researchers measured the thickness of "fibres" that carry inputs from the cortex to the basal ganglia.
Brown says the technology allows researchers to "track millimetre by millimetre which direction fibres in the grey matter are travelling," and determine the number (or thickness) of fibres connecting one region to another.
These measurements were done when the participants were not making decisions. They were also required to undertake a series of tasks that required them to make decisions either quickly or slowly.
They found those with the stronger connections in the brain were more able to move flexibly between a fast response and a more accurate slow response.
The study was based on only nine participants, however, the researchers used a previous independent study, which had included MRI scans, to verify their findings.
'Train the brain'
Brown says their work could help in tracking cognitive decline in aging.
"People who have a disease of aging often have their symptoms exacerbated by the slowing that comes with aging," he says.
"If you can understand the slowing, we might be able to separate the effects and better understand what is happening."
He says there is a view that older people are slow and cautious because they choose to be so.
However, these latest findings would suggest that as brain connections thin, the person is "stuck in a regime where response is always slow and cautious."
In current work, Brown says they are trying to force older participants to be faster at decision-making.
"We are seeing if you can train the brain to use these tracks more efficiently," he says.