Keeping you up-to-date on recent headlines in neurology.

New technology helps Parkinson's patients speak louder ... Researchers have developed a new technology that helps Parkinson's patients overcome the tendency to speak too quietly by playing a recording of ambient sound, which resembles the noisy chatter of a restaurant full of patrons. "People with Parkinson's disease commonly have voice and speech problems," said Jessica Huber, an associate professor in Purdue's Department of Speech, Language and Hearing Sciences (West Lafayette, Indiana). "At some point in their disease they will have some form of voice or speech disorder that generally occurs a little later in the disease." Parkinson's affects 1.5 million people in the U.S. and is one of the most common degenerative neurological diseases. About 89% of those with Parkinson's have voice-related change, which is related to how loudly they speak, and about 45% have speech-related change, or how clearly they speak. In Huber's experiment, patients were asked to speak louder while a recording of background "multitalker babble noise" was played. The noise is essentially the sound of a restaurant full of patrons, but without clattering silverware and clinking glasses. The background sound elicits a well-known phenomenon called the Lombard effect, a reflex in which people automatically speak louder in the presence of background sound. Huber created a new electronic technology using this principle. The voice-activated device automatically plays the background babble when the person begins to speak.

Obese people are at greater risk for developing Alzheimer's ... Obesity is on a rampage, with the World Health Organization pegging the numbers at more than 300 million worldwide, with a billion more overweight. With obesity comes the increased risk for cardiovascular disease, Type 2 diabetes, and hypertension. Now comes more discouraging news. In the current online edition of the journal Human Brain Mapping, Paul Thompson, senior author and a UCLA professor of neurology, and lead author Cyrus Raji, a medical student at the University of Pittsburgh School of Medicine compared the brains of people who were obese, overweight, and of normal weight, to see if they had differences in brain structure; that is, did their brains look equally healthy. They found that obese people had 8% less brain tissue than people with normal weight, while overweight people had 4% less tissue. According to Thompson, who is also a member of UCLA's Laboratory of Neuro Imaging, this is the first time anyone has established a link between being overweight and having what he describes as "severe brain degeneration." In looking at both grey matter and white matter of the brain, they found that the people defined as obese had lost brain tissue in the frontal and temporal lobes, areas of the brain critical for planning and memory, and in the anterior cingulate gyrus (attention and executive functions), hippocampus (long-term memory) and basal ganglia (movement). Overweight people showed brain loss in the basal ganglia, the corona radiata, white matter comprised of axons, and the parietal lobe (sensory lobe). "The brains of obese people looked 16 years older than the brains of those who were lean, and in overweight people looked eight years older," says Thompson.

Phenylketonuria research to be presented at conference ... Genetic researchers at Children's Memorial Hospital (Chicago) are aggressively identifying adult patients who suffer from the genetic disorder, Phenylketonuria (PKU), and are presenting those findings at the 11th International Congress of Inborn Errors of Metabolism in San Diego, August 29 through September 2. The findings have also been published in the current issue of Molecular Genetics and Metabolism. PKU is a lifelong genetic disorder in which a deficient enzyme prevents the body from metabolizing an essential amino acid, called Phenylalanine (Phe), which is found in most foods including meat, bread, eggs, dairy, nuts, and some fruits and vegetables. When left untreated, PKU patients who consume too much Phe are at risk for severe neurological complications, including IQ loss, memory loss, concentration problems, mood disorders, and in some cases, severe mental retardation. "It is so important for adults with PKU to know that it is never too late to address the disorder and resume treatment," said Barbara Burton, MD, Director of the PKU and Metabolic Disease Program at Children's Memorial. "When PKU is no longer managed, that is when we see patients who suffer from mood and social disorders. For adults, this can also impact their concentration at work, stability in relationships and social interactions. As a healthcare provider, I feel that it is our responsibility to educate adult PKU patients and offer comprehensive medical care and social support systems."

Fly eyes help see new memory proteins ... With more than 1,500 eyes, not much escapes the fruit fly's sight. Now, a new research report in the journal Genetics, describes how researchers from the U.S and Ireland used those eyes to "see" new proteins necessary for memory. In addition to shedding light on this critical neurological process, the study also provides information on a form of mental retardation in humans. "Understanding translational control mechanisms in the brain teaches us how the brain learns and adapts, and will inform the design of treatments for specific types of neurologic disease," said Anne-Marie Cziko, at the University of Arizona (Tucson) and co-author of the study. Specifically, the scientists found that the "fragile X mental retardation protein," which plays a crucial role in the cellular processes involved in learning and memory, needs five other proteins to function normally. The scientists identified these proteins using an artificial system of increasing fragile X mental retardation protein in the eyes of fruit flies. Its high level leads to visible deformities in a fly's eyes. To test the requirement of various candidate proteins for function of the fragile X mental retardation protein, the researchers genetically modified the flies to prevent them from making each candidate protein. They found that loss of any one of the five proteins caused the fruit fly's eye to be significantly less deformed, revealing that each is required for function of the fragile X mental retardation protein. This finding and the identification of the five new proteins that interact with the fragile X mental retardation protein give new insight into additional and alternative functions of fragile X mental retardation protein. They also indicate the need for more study into the fragile X mental retardation protein's function itself.

Study sheds light on prion disease ... A new study shows that nervous system integrity and axonal properties may play a key role in prion diseases. The findings, from researchers at the Rudolf Virchow Center and the Institute of Virology of the University of Würzburg in Germany, expand the understanding of the development of prion disease and suggest novel targets for therapeutic and diagnostic approaches in its early stages. Details are published August 21 in the open-access journal PLoS Pathogens. Despite growing awareness of prion diseases, such as bovine spongiform encephalopathy (BSE) and the human variant, Creutzfeldt-Jakob disease, the molecular mechanisms responsible for their development are still not completely understood. These diseases are associated with neuropathological symptoms that include dementia, motor system defects and amnesia, although previous observations identified molecular hallmarks in the absence of these neuropathological symptoms, creating a paradox. Impaired axonal transport is known to be involved in the development of neurodegenerative disorders like Alzheimer's or Parkinson's diseases. Previously, prion infections were shown to cause spongiform vacuolations, axonal swellings and accumulation of amyloid protein fibrils. Impaired axonal transport had not been observed so far. To monitor the axonal transport, Ermolayev injected special dyes into mouse motor neurons, using a combination of confocal and novel ultramicroscopy techniques to monitor the dye delivery to the neurons and characterize the functional properties of axonal transport. After prion injection into the brain and motor neuron system, the researchers observed the described clinical symptoms. When clinical symptoms occurred, the researchers found a clearly reduced axonal transport in the neurons of two brain centers, the red nucleus and the motor cortex. Axonal transport impairments were seen in 45 per cent of neurons in the red nucleus and up to 94% of motor cortex neurons.

— Compiled by Rob Kimball, MDD; robert.kimball@achmedia.com