PSP: SOME ANSWERS( continued)
Probably the most important part of dealing with PSP is for the patient’ s family to understand that the problems with visual inattention and personality changes are part of the illness. The patient is not lacking willpower nor“ faking.” Furthermore, many of the problems in PSP are intermittent and can be aggravated by the patient’ s mental or emotional state. For example, walking, writing, and eating may be poor one hour and better the next. The family should understand that these fluctuations are not under the patient’ s control and that nagging and shouting usually make matters worse. A wise policy is to be prepared to take advantage of the good periods to have an outing, a relaxing shower, or some other activity that would be more difficult at another time.
Walking aids are often important for patients with PSP. If a walker is required, it should be weighted in front with sandbags over the lower rung because of the tendency for PSP patients to fall backwards. A better but more expensive solution is a large, heavy walker resembling a small shopping cart with three or four fat, soft rubber wheels and a hand brake. The tendency to fall backwards can also be countered by the use of built-up heels. Leg braces are not helpful because the problem in PSP is coordination and balance rather than actual muscle weakness.
Shoes with smooth soles are often better than rubber-soled athletic shoes. In many people with PSP, the gait disorder includes some element of“ freezing,” a phenomenon that makes it difficult to lift a foot from the ground to initiate gait. People with such symptoms can fall if they move their body forward before the foot moves. In these cases, smooth soles could make it easier to slide the first foot forward.
16
Handrails installed in the home, especially in the bathroom, may also be helpful. The difficulty looking down dictates that low objects, such as throw rugs and low coffee tables, be removed from the patient’ s living space.
To remedy the difficulty of looking down, bifocals or special prism glasses are sometimes prescribed for people with PSP. These are worth trying but can be of limited value because there is not only a problem moving the eyes in PSP but also a problem directing the person’ s attention( the“ mind’ s eye”) to objects located below the eyes.
What is the cause of PSP?
The symptoms of PSP are caused by a gradual deterioration of brain cells in a few tiny but important places in the base of the brain. The most important such place, the substantia nigra( pronounced sub-STAN-cha NYE-gra), is also affected in Parkinson’ s disease. Damage to it accounts for the symptoms that PSP and Parkinson’ s have in common. However, several important areas that are affected in PSP are normal in Parkinson’ s, and vice versa. And, under the microscope, the appearance of the damaged brain cells in PSP is quite different from those in Parkinson’ s and instead resembles the degeneration in Alzheimer’ s disease. In addition, the location of the damaged cells is quite different in PSP and Alzheimer’ s. Also, PSP lacks amyloid plaques, which are deposits of waxy protein that are a hallmark of Alzheimer’ s.
But what causes the brain cells to degenerate in the first place?
No one knows yet, but we have some clues. In the brain cells that are degenerating in PSP, there is an abnormal accumulation of the normal protein tau. These clumps of tau, once they reach a size that can be seen through a microscope, are called neurofibrillary tangles. The normal function of tau is to help support the microtubules, which have two important jobs: one is to form the internal“ skeleton” of the brain cells, and the other is to serve as a“ monorail” system, transporting nutrients around the cell. We don’ t know whether the problem is that the tau is defective from the time of its manufacture or if it is damaged later, or even if it remains normal but is produced in excess. If it is damaged, the nature of that damage could be the excessive attachment of phosphate( see the section on PSP preventive drugs). Or, the excessive phosphates