The Cognitive Effects Of Chiari

Cognitive problems in Chiari 1 Malformation are frequently noted. Dr. John Oro wrote in his article Chiari and Syringomyelia 101 (found on the American Syringomyelia Alliance Project website, ) that general symptoms of depression, poor sleep and fatigue are described by his Chiari patients. Some patients described feelings of "brain fog" or difficulty with concentration and thinking, including difficulties with word finding. It is also significant that he and his nurse associate Dr. Diane Mueller published a study this year acknowledging that this symptom group demonstrated little improvement following decompression surgery.

The reason for this is not clear. But the reason may lie in the fact that these cognitive problems may have different etiologies - that is, they may arise for different reasons, even though all patients had Chiari 1 malformation.

The cause of cognitive problems has not been studied in Chiari 1 malformation. Our experience reveals that is difficult enough to convince physicians of our ongoing medical issues. The one group of physicians that believe and understand our physical problem, the neurosurgeons, is busy fixing our physical malformations. The physicians that do have some knowledge of how the brain works, the neurologists, do not seem to have a good understanding of Chiari malformation. And many patients find that if they begin to discuss issues as "brain fog" and difficulty with concentration, word drop, etc., they have gone beyond most physicians areas of expertise.

As a pediatric physician, I have some experience in dealing with children with attention problems and focusing. I believe that we can use a similar approach to those of us that have Chiari 1 malformation and cognitive issues. Some potential causes of cognitive problems may include:

1) Attention deficit disorder (ADD) has been well described in children (incidence of 3 to 5 % in children) and newer evidence has shown that this disorder does not disappear as we age. The diagnosis of ADD requires symptoms for greater than 6 months to a degree that is maladaptive and involves areas of inattention, hyperactivity, and impulsivity. In adulthood, women with ADD are likely to have mood and anxiety disorders and men are more likely to have substance abuse issues.

2) Cognitive skills decline in adults with age. The adult type of Chiari 1 malformation is frequently diagnosed in the third or fourth decade and by that point, many of us are feeling the natural effects of aging on our brain. Though surgery may help our physical ailments, it will not reverse this aging process and our feelings of "decreasing brain function" will not be affected.

3) Pain is the most common complaint in Chiari 1 malformation. Long term, unmanaged pain can cause people to withdraw from family and friends and leave them unable to care for children, hold steady jobs, and at times even face a personal future. Many of us can appreciate that pain can affect our ability to concentrate, multi-task, etc.

4) Medications that many of us take to manage our pain symptoms may interfere with our thinking processes. Pain medications, especially the opiate class, are known to have short term manifestations including sedative properties. Tolerance may develop over time but certainly may affect our thought processes. Other drug classes are known to have sedative potentials-- seizure medications, anti-histamine medications, anti-anxiety medications, etc frequently have warnings about somnolence.

5) Hormonal abnormalities can affect our ability to concentrate. Some Chiarians are known to have abnormalities in their pituitary function which may influence hormone levels. Thyroid abnormalities, both hyper- (too much) and hypo- (too little) are known to have effects on concentration. Changes in other hormonal levels (e.g. the changes found with menopause) have been shown to decrease some cognitive functions.

6) Sleep-disordered disturbances, especially those associated with sleep apnea (prolonged cessation in breathing), have been shown to decrease cognitive skills. Chiarians may present with central apnea, hypoventilation, and hypoxia. Those with sleep apnea may have depression of the respiratory center or cranial nerve dysfunction involving the vocal cords or the muscles associated with the airway. K. Archbold, et al (Journal of Pediatrics 140: 97-102) in 2002 described symptoms of sleep disturbances in children that directly impacted cognitive skills such as inattentiveness, hyperactivity, impaired cognitive function, and emotional stability.

7) Depression has long been recognized to cause problems with attention span and decisiveness. Functional imaging scans have demonstrated decreased neuronal activity in the left lateral prefrontal cortex associated with the degree of depression. Also studies of elderly depressed patients show decrease of cerebral brain metabolism throughout the brain.

8) OTHER-Dr. Paolo Bolognese, neurosurgeon at the Chiari Institute in New York, postulated in a quick posting on the World Arnold Chiari Malformation Association list server that elevated CSF pressure caused by Chiari 1 malformation might "intoxicate" the thinking part of the brain causing "brain fog". Alternatively, the Chiari malformation might interfere with controlling the signals traveling within our brains and thus affect intellect.

Obviously, each of these etiologies of diminished cognition, concentration, difficulties with word finding and/or multitasking requires different treatments. ADD and other processing difficulties may be clinically diagnosed and treated with stimulants. Neuropsychologists may be able to demonstrate the specific area of the brain affected or the defective processing through specific testing. Functional brain imaging is increasing in usage in the field of cognitive neuroscience. Pain medications need to be monitored for their potential side effects. Blood testing may demonstrate hormonal imbalance and subsequently be treated. Treatments for sleep apnea and specific sleep aids may alleviate sleep disturbances and perhaps their effects on cognition. Other medications may be needed for depression.

As outcomes measures and research programs are being developed, it will be useful to define and study "brain fog" so that we will be able to function optimally.

Ed. Note: The opinions expressed above are solely those of the author. They do not represent the opinions of the editor, publisher, or this publication. Anyone with a medical problem is strongly encouraged to seek professional medical care.