Progressive supranuclear palsy (PSP) is considered a rare disorder, yet it is the second most common neurodegenerative cause of parkinsonism seen in movement disorder clinics. Like other neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, the risk of developing PSP increases with age. Thus, the prevalence (number of individuals having a disease at a given time) of PSP will steadily increase over the coming years as the Baby Boom generation ages. These facts underscore the need for an increased research effort directed at finding the cause and cure of the disease as well as a focused approach to medical management and caregiver support. There should also be an effort to increase awareness among physicians and the public at large to the special needs of patients with PSP.
Patients with PSP and their caregivers often face a confusing period before the diagnosis is eventually made. When first seen by the family physician, the patient might be told that the symptoms are due to a stroke or to Parkinson's disease. Quite likely, an MRI or CT brain scan will be performed and interpreted as being "unremarkable" or showing "nonspecific" changes. Following a referral to the neurologist, the patient will, in all probability, be diagnosed as having Parkinson's disease and be placed on an antiparkinsonian drug such as carbidopa/levodopa (Sinemet). Since many individuals with PSP will derive some benefit from this drug, the diagnosis of Parkinson's disease may well persist for some time. There may also be a referral to a local Parkinson's disease support group, but it will soon become evident that many of the problems faced by the patient with PSP are quite different from those faced by patients with Parkinson's disease.
This sequence of events is not the result of incompetence or lack of compassion; rather, it stems from the fact that the clinical features specific to PSP may not clearly emerge until several years following the initial visit to the neurologist. Furthermore, even when the diagnosis is suspected, there may be reticence on the part of the neurologist to communicate suspected PSP to the patient or the patient's family, since the diagnosis is generally less optimistic than that of Parkinson's disease. Nonetheless, in the majority of cases, the clinical "features" of PSP can be quite distinct and the problems faced by patients and caregivers are quite different from those of Parkinson's disease. Thus, it is important for the patient's doctors and caregivers to recognize and deal with these specific problems as early as possible.
Although the clinical spectrum of PSP is variable, some of the major problems faced by patients and caregivers include: visual symptoms, impaired balance leading to falls, speech and swallowing difficulties, personality and mood changes and sleep disturbances. Some of these symptoms will emerge late in the course of the disease, but others develop early. Each of these problems presents a separate management challenge.
The hallmark clinical feature of PSP is a disturbance of eye movement from which the term progressive supranuclear palsy is derived. In particular, this refers to the inability for patients to look down on command, yet when the head is tilted by the examiner, the eyes can be induced to deviate down. Thus, there is no paralysis of the eye muscle or the neurons in the nuclei directly responsible for down gaze. Rather, the problem is "supranuclear," or above these nuclei. Some patients with PSP will not manifest definitive down-gaze palsy until later in the course of the disease. Other eye movement problems can occur in this disease as well, including impairment of quick eye movements, slowing of visual pursuit (i.e., following a moving object), instability of fixation, and a disturbance of convergence (needed for binocular focusing on close objects). These eye movement problems result in a number of visual symptoms including blurred vision, occasional double vision, and reading difficulty, all of which may further compound problems with gait and balance. Some patients will also develop a problem with eye opening due to either blepharospasm (a form of dystonia resulting in forced eye closure) or eyelid apraxia (difficulty with voluntary eye opening). Both of these conditions have been treated with botulinum toxin (Botoxl) injections in the eyelid and muscles surrounding the eye, although it appears that blepharospasm responds best to this procedure. These visual symptoms are best evaluated by an ophthalmologist familiar with neurological disease. The neuroophthalmologist can provide visual aids such as prism lenses and tinted lenses, botulinum toxin (Botoxl) injection and even lid crutches to help patients with these visual problems.
Impairment of gait and balance is one of the earliest symptoms experienced by patients with PSP. In fact, unexpected falls, a symptom that rarely if ever occurs in the early stages of Parkinson's disease, often prompt the first referral to a neurologist. This symptom requires immediate attention because, all too frequently, these falls result in serious injuries such as a fracture or concussion. A physical therapist familiar with neurological diseases can be of great assistance in providing gait training, preventative measures aimed at avoiding or buffering falls, in-home safety measures such as grab bars for the hallways and bathrooms, and assessing the need for an appropriate walking aid or wheelchair. Because of the tendency for some patients with PSP to fall backward, a walker may not provide adequate protection, although there are now a wide variety of walkers available including some that provide some protection against backward falls. The decision to use a wheelchair is often one of the most difficult faced by patient and family, because it may be perceived as giving in to the disease or losing independence. Yet, a walking aid or wheelchair may actually reduce dependence on the caregiver and even allow the patient a wider range of activity. Importantly, these devices will reduce the risk of a serious injury stemming from a fall with the possibility of hospitalization and surgery. Although it is never easy to accept the need for a walker or a wheelchair, the patient and caregivers must keep in mind the progressive nature of this disease and the fact that these aids will likely improve the patient's quality of life.
Patients with PSP can develop a severe impairment of speech and swallowing. These problems are linked to neuronal damage within the brainstem and their connection to higher brain centers, especially the basal ganglia. Impaired function of the muscles involved in speech and swallowing appear to be a complicated mixture of slowed reflexes and dystonia (involuntary muscle contraction). Swallowing problems are known as "dysphagia" and speech problems as "dysarthria." The most serious complication of dysphagia is aspiration of food into the lungs resulting in pneumonia. Thus, it is vitally important for the patient with PSP to undergo a speech and swallowing evaluation periodically. A comprehensive examination of swallowing involves using fluoroscopy and video recording to image a bolus of food as it travels from mouth to stomach. By using different consistencies of food, this examination can detect which foods are best tolerated and whether or not there is any aspiration. This examination is also an important factor in determining whether or not the patient should have a gastrostomy tube placed. A gastrostomy procedure involves inserting a plastic tube directly into the stomach through an opening in the abdomen and stomach wall. Its purpose is to provide a route for food and liquids that bypasses the mouth and esophagus, thus providing adequate nutrition and minimizing the risk of aspiration pneumonia.
Unquestionably, the placement of a gastrostomy tube is a major decision by the patient and caregiver as it is often perceived as an ominous sign of disease progression. However, in most cases, a gastrostomy tube will improve the patient's quality of life because it allows for adequate nutrition, minimizes the chance of aspiration pneumonia and reduces caregiver anxiety.
It is not uncommon for patients with PSP to exhibit personality and mood changes. As reported by Dr. Litvan (PSP ADVOCATE, second quarter, 1997), patients often become uninterested in their surroundings and tend to avoid interacting socially (i.e., they become apathetic). Occasionally, they will exhibit inappropriate behavior quite different than their personality prior to developing PSP. In addition, the patient may exhibit sudden bouts of crying or laughing, often referred to as "emotional incontinence." Personality and mood changes can be very disturbing to the family and can be so striking as to undermine the relationship between patient and caregiver; these changes are further complicated by certain cognitive deficits such as mental slowing and impaired memory. Thus, it is important for the family and caregivers to realize that these changes are part of the underlying disease process and to communicate such issues to the family physician and neurologists. Psychiatric counseling can be very helpful in these situations and, although depression may not be a major feature of PSP, certain antidepressants can be of some benefit.
A variety of sleep disturbances can be associated with PSP, including insomnia, frequent awakenings (often related to bladder urgency), sleep apnea (periodic cessation of breathing), periodic limb movement during sleep and "REM sleep behavioral syndrome" (disinhibited movements related to dream activity, which can sometimes be violent) and hypersomnia (excessive sleep). This unusual sleep activity can be confusing, not to mention disturbing for family and particularly for the spouse. Again, it must be recognized that these symptoms are related to the underlying disease process and that there are treatments available. It is most helpful for the patient to undergo a comprehensive sleep study to characterize the sleep disturbance. Sleep centers operated by experts in sleep disorders can be found near most major medical centers throughout the country and are often overseen by neurologists. For those with REM sleep behavior syndrome, small amounts of a drug called clonazepam can be helpful. For sleep apnea, a variety of drugs may be of some benefit and in more severe cases the use of an apparatus that opens up the airway by means of nasal continuous positive airway pressure (CPAP) can result in improved sleep.
There is no question that PSP can present a formidable challenge for patients, treating physicians, and caregivers alike, but it is wrong to assume that nothing can be done. Sometimes the decisions are quite difficult, such as deciding on a wheelchair or a gastrostomy tube, but as yet there is no cure for the disease and attention should therefore be centered on maximizing the patient's quality of life until the time when a better treatment and, hopefully, a cure are discovered.
Over the past few years there has been a steady increase in PSP awareness as well as an increasing understanding of the factors associated with nerve cell damage in this disorder. One of the factors involves an important nerve cell protein called "tau," which plays a major role in supporting "microtubules" responsible for transporting chemicals throughout the cell. Tau is produced in several different forms (isoforms) and in PSP there are specific isoforms that accumulate in neurons and glial cells (cells that support neurons). Determining the mechanisms by which tau accumulates and the reason why only certain cells are affected will likely bring us closer to finding the cause of this disease. Thus, research efforts in PSP have now finally begun to see a definite glimmer of light in that which has been a long dark tunnel for so many years.
The PSP Advocate has provided patients and caregivers with up-to-date information on PSP, and support groups are now emerging throughout the country. The disclosure by Dudley Moore of his battle with PSP has also helped increase public awareness of this disease. Financial support for PSP research, like the generous gift by Jay Troxel, is now yielding results, but clearly, more funding is needed. Now, for the first time, we can look forward with optimism to finding the cause of PSP and, in the near future, developing a cure.
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