New research suggests that the first signs of dementia and Alzheimer’s disease (AD) may be physical, rather than mental. Poor physical function may precede the onset of dementia and AD and higher levels of physical function may be associated with a delayed onset of disease.
The prospective cohort study of 2288 people aged 65 years or older without dementia, from the Group Health Cooperative and the University of Washington, (WA, USA) was published in the May 22 issue of the Archives of Internal Medicine. Enrolment occurred between 1994 and 1996 and study participants were followed up every 2 years until October 2003. In the follow up, physical and mental functioning were assessed.
A total of 319 participants developed dementia (221 had AD) during follow up. The results showed that individuals whose physical function was higher at the start of the study were three-times less likely to develop dementia than those whose physical function was weak.
“Everyone had expected the earliest signs of dementia would be subtle cognitive changes”, said Eric B Larson, Director of Group Health Center for Health Studies. “We were surprised to find that physical changes can precede declines in thinking”.
Thus, although dementia and AD are considered a brain disease, physical fitness could also be involved. The study found that problems with walking and balance seemed to be the first indicators of future dementia, whereas a weak handgrip seemed to be a later sign of dementia development in older people.
An earlier report in the Annals of Internal Medicine, published in January 2006, also highlighted the potential link between physical fitness and dementia and AD. In the study, people who exercised regularly were less likely to develop dementia, including AD, although the cause was not clear. However, this new study provides evidence of a possible pathway – regular exercise may help to keep dementia at bay by improving and maintaining physical conditioning.
“These results suggest that in aging, there’s a close link between the mind and the body”, said Larson. “Physical and mental performance may go hand in hand, and anything you can do to improve one is likely to improve the other”. However, the authors believe that it is still possible for someone with physical constraints to stay mentally alert and cognitively fit.
Body language understanding limited by schizophrenia
A study published in the April 2006 issue of Schizophrenia Research aimed to determine whether patients with schizophrenia have deficits in the appraisal of socially relevant stimuli. It found that people with schizophrenia are not fluent in understanding body language, something that comes easily to many people.
The researchers, from the University of Iowa, California Institute of Technology and University of Pennsylvania, USA, found that their results applied even to those with mild-to-moderate symptoms and who take medication. Previous results have shown that schizophrenia patients have trouble deciphering emotion from human facial expressions, although, until now, it was not well understood whether this perception problem extended to other socially relevant clues.
“As we interact with people, we make judgements that we’re not consciously aware of”, said Sergio Paradiso, Assistant Professor of Psychiatry in the University of Iowa Roy J and Lucille A Carver College of Medicine. “If we see a coworker hunched over and don’t see his face, we may approach him cautiously because we think something might be wrong and perhaps we can help. We don’t see the face, but we glean information from the body language. People with schizophrenia are not as good at extracting this kind of information to guide their social interactions”.
The study group comprised 20 schizophrenia patients who were taking medication and 14 healthy volunteers equated for parental socioeconomic status. The researchers tested their recognition of gender stimuli, emotional people stimuli and emotional scenes. In one test, participants watched a video of moving human bodies. The images were manipulated so that no facial features or body shapes could be seen; rather, points of light that were visible when they moved were attached to the joints of people on the screen. Study participants were asked, based on the speed and pattern of bright dots, to determine if the motion depicted, for example, joy or sadness. Study participants were also asked to determine the mood of people in a film clip with the actors’ faces erased versus faces present. Individuals with schizophrenia showed poorer identification of happiness, anger and fear across all tasks.
“This film clip test showed that patients with schizophrenia have problems with both taking advantage of extra information that is conveyed by the human face and with deciphering socially relevant stimuli that are not conveyed by facial expression”, said Paradiso.
Research should now move to determining whether people with schizophrenia can learn to perceive body posture and other social clues. The researchers believe this is an important question, which should be examined at the neuroscientific level, to determine whether, following rehabilitation, regions of the brain can take over and support social perception abilities.
“The idea of other circuits taking over the brain for specific mental capabilities is not new. There’s some degree of redundancy in the brain so that when a specific faculty is affected another part of the brain attempts to take over. It may occur in people who have had a stroke, usually through rehabilitation”, said Paradiso.
Predictors of bipolar risk identified
Five predictors for the risk of bipolar disorder in patients who have been unsuccessfully treated with antidepressants have been identified in a new study. Presented at the 159th Annual Scientific Meeting of the American Psychiatric Association (Toronto, Canada), the study concluded that these risk factors included: anxiety, feelings of people being unfriendly, family history of bipolar disorder, a recent diagnosis of depression and legal problems.
Bipolar disorder (manic-depressive disorder) is a serious mental illness, which can affect a person’s ability to feel a normal range of moods. Sufferers have extreme shifts in thoughts, energy, mood and behaviour. Bipolar disorder is a lifelong condition but can usually be managed effectively with proper medication, education and support. However, it can often be misdiagnosed as major depression or other disorders.
The study aimed to identify predictors of bipolar disorder risk among patients treated for major depression. Of patients enrolled in the study, 43% who responded positively to any three risk factors also screened positive for bipolar disorder, according to the Mood Disorder Questionnaire (MDQ), which is a validated screener for bipolar disorder. A third of patients whose depression medication was not right for them, who had been told by a doctor that they had anxiety and also felt that people were not friendly towards them, also screened positive for bipolar disorder using the MDQ.
“Bipolar depression may be difficult for both patients and doctors to identify because the symptoms are often confused with major depression”, said Joseph R Calabrese, Professor of Psychiatry, Case Western Reserve University and Director, Mood Disorders Program, University Hospitals of Cleveland. “Given the difficulty of diagnosing bipolar disorder, the five predictors identified in this study may help physicians better assess a patient’s risk for bipolar disorder, which could lead to more effective treatment”.
These results coincide with previous research suggesting that nearly half of patients with bipolar disorder will first be diagnosed with major depression. The illness can be made more difficult to treat following inappropriate treatment as a result of misdiagnosis. Antidepressants alone can induce mania or hypomania in some bipolar disorder patients. In addition, individuals with untreated bipolar disorder can experience a greater frequency of manic and depressive episodes, resulting in significant disruption of their professional and personal lives.
“Many people with bipolar depression face up to 10 years of coping with symptoms before getting an accurate diagnosis”, said Karl Ackerman, President of the Manic-Depressive and Depressive Association of Boston. A brief assessment tool that can be used to identify bipolar disorder risk was created based on these recent findings. Hopefully this tool will prove helpful to patients coping with medication-resistant depression and physicians trying to diagnose bipolar disorder.
Lead exposure: later brain cell loss and damage
A new study, published in the May 23 issue of Neurology, has found that people who worked with lead 18 years previously now have significant loss of brain cells and damage to brain tissue.
Former employees of a chemical manufacturing plant, who had not been exposed to lead for an average of 18 years and who had worked at the plant for an average of more than 8 years, were assessed in the study. The researchers measured the amount of lead accumulated in the workers’ bones and used magnetic resonance imaging scans to measure the workers’ brain volumes and to look for white matter lesions or small areas of damage to the brain tissue.
The higher the lead levels of the workers were, the more likely they were to have smaller brain volumes and greater amounts of brain damage. Of the 532 participants, 36% had white matter lesions and those with the highest lead levels were more than twice as likely to have brain damage as those with the lowest lead levels and their brain volumes were 1.1% smaller than those with the lowest lead levels.
“The effect of lead exposure was equivalent to what would be expected for 5 years of aging”, said study author Walter F Stewart of the Center for Health Research of the Geisinger Health System in Danville, PA, USA, and the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, USA. “These effects are the result of persistent changes in the structure of the brain, not short-term changes in the brain’s neurochemistry”, he continued.
According to Andrew S Rowland of the University of New Mexico, Albuquerque, this study raises new questions. “There have been many studies done on the effects of lead on children’s IQ, but the possible effects in other areas, such as attention, aggression, or any mental disorders, have gotten less attention. Exposure to inorganic lead, like that found in paint, remains an important public health problem. And those of us who grew up before the late 1970s still carry high lead levels in our bodies. We need more studies addressing the potential chronic health effects of those exposures”.