Progressive Supranuclear Palsy: A Neurophysiological Report :: Biology Essays Research Papers

Progressive Supranuclear Palsy: A Neurophysiological Report Progressive Supranuclear Palsy (PSP) is a rare neurodegenerative disorder categorized as a form of parkinsonism. First described in 1964 by three Canadian neurologists, PSP is sometimes referred to as Steele-Richardson-Olszewski Syndrome, or Nuchal Dystonia Dementia Syndrome (1). Progressive damage to multiple brain cells associated with deterioration of the myelin sheath that speeds up nerve impulse conduction, as well as destruction of the entire nerve (2), result in severe and irreversible problems controlling balance, eye movement, breathing, and voluntary muscle movement (3). The actor Dudley Moore has been diagnosed with PSP and presently works to improve awareness and treatment of this enigmatic disease. Although PSP is frequently misdiagnosed as Parkinson's, the disorder progresses much more quickly, maintaining very unique and exclusive manifestations. Individuals suffering from PSP present clinically with akinetic rigid syndrome, gait ataxia, and supranuclear vertical-gaze palsy (4). Akinesia refers to the loss of control of voluntary muscle movements. This is expressed in loss of balance while walking and recurrent falls. A permanent "Mona Lisa" stare and wide-eyed expression is often described, in addition to guttural, slurred speech and swallowing difficulties (5). These facial distortions result from nerve damage controlling the facial muscles. All PSP individuals suffer from some degree of vertical-gaze palsy, in which the ability to move the eyes up-and-down is impaired (4). Muscles in the back of the neck and spine are usually severely affected, resulting in a retro-collis posture; the individual appears to perpetually look up toward the ceiling. Rigidity in the limbs is al so observed, although to a lesser degree. If rigidity does exist here, it is equal on both sides of the body. In Parkinson's disease, rigidity is more prominent and pronounced in the limbs, favoring one side more that the other (6). None of the tremors characteristic of Parkinson's are observed in PSP. Personality changes and dementia are also noted, particularly later in the development of the disease. PSP affects the brainstem, basal ganglia, and cerebellum. The brainstem controls involuntary movements such as breathing and heart rate. Three divisions of the brainstem have been delineated: the medulla oblongata, the pons, and the midbrain. In PSP, all three sections are affected. The pons controls facial nerves and eye muscles, while the midbrain is the visual center of the brain (3). The medulla (sometimes referred to as the "bulb") maintains speech and swallowing abilities. Paralysis here results in impairment of these functions.