Auto-immune diseases affecting cognition are not rare in neuropsychology however, Neuro-Behcets certainly is! So when it arrived on my doorstep I had to share. What Is Neuro-Behcets (pronounced “Beh- shet”)? It is a chronic multi-system relapsing inflammatory disorder resulting in ulcers in the mouth, genitals, appendages, stomach and intestines. When it manifests in the brain it affects the brain stem, the meninges, cortical and sub-cortical pathways, and other brain structures. There are two types of Neuro-Behcets (NBD), Parenchymal (affecting brainstem, spinal cord, cerebral hemispheres) and non-parenchymal (causing intracranial hypertension, aseptic meningitis, cranial neuropathy and cerebrovascular disorders including aneurysms, vasculitis and occlusions). It is the most dangerous manifestation of Behcets disease and can affect or ‘attack’ cortical as well as subcortical structures in the brain.
Examples of cortical disease can be found in Alzheimers type dementia (AD), Pick’s disease, and Creutzfeldt-Jacob’s disease, which are associated with abnormalities primarily in the hippocampus, cortex association areas, and medial temporal lobes, a.k.a. cortical structures. The effects of cortical dysfunction can include cognitive deficits in language, learning, perception, calculation, and praxis.
Sub-cortical dysfunction constitute extra-pyramidal disorders (such as Huntingtons Disease, Parkinsons Disease, and Supranuclear Palsy [PSP]) are associated with abnormalities in the basal ganglia, thalamus, and brainstem structures. These disorders tend to produce disturbances in motivation, mood, attention/concentration, cognitive processing speed, and executive function.
But before we go off into the distinctions between cortical versus sub-cortical deficits lets get back to fascinating Behcets.
The Neuropsychological profile of NBD is as heterogenous as the disease itself, as the functional deficits depend on the area of the ‘attack’ and so may be different over the course of the disease. One key aspect of NBD is retrieval deficits, among others, indicating sub-cortical defect. Now having a cortical or subcortical dysfunctional effect depends on the brain structures involved in different neurological disorders, and in particular the area of the brain inflamed by Behcets disease.
So, neuropsychological deficits will be concentrated in areas most affected by the disease at the time of the attack. These deficits may resolve in the acute phase or may become more chronic and unalterable. They key to ensuring resolution is aggressive management with a host of sometimes toxic medications and steroids designed to halt the immune system devouring itself.
Basically, the neuropsychological deficits you can expect to find center around learning, concentration and attention, processing speed and retrieval, impaired psychomotor speed and dexterity as well as changes in mood and personality. Some persons describe explosive outbursts for no reason combined with feelings of apathy and nonchalance making it sound like depression but with no clear extenuating symptoms or quick resolution of symptoms in a matter of days. In even rarer cases, NBD can lead to dementia or death from a stroke affecting the brain stem or basal ganglia.
But we wont focus on the rare outcomes here, rather the positive effects aggressive management of attacks can result in improvement in memory retrieval, motor functioning, and executive functioning with the help of neuro-rehabilitation. But more on that later. For now consider this an introduction to the neuropsychological profile of rare disorders archive. Please check out the Behcets Syndrome Society’s page for additional information and links to free articles or abstracts!
I will post more on rare neurological disorders and how we can help as we go along this year! Enjoy.
Dr. Tammy Haynes 