Dementia implies problems with cognition (thinking), and this is a fundamental component of DLB and PDD. Dementia also implies that the cognitive problems are sufficiently troublesome to affect activities of daily living. Less severe impairment of memory or thinking that does not interfere with daily activities is classified as mild cognitive impairment (MCI). MCI may be a prelude to dementia. If MCI accompanies parkinsonism, then the treatment strategies outlined in this text are appropriate. Dementia does not necessarily mean that a rapid progression to an advanced state is inevitable. Dementia may be relatively mild and well compensated, especially with the help of the spouse and family; it may remain that way for years. The cognitive profile of DLB and PDD was described in Chapter 4. To review, this impairment affects several major components of intellect. This includes executive function, localized to the frontal lobes of the brain. Visuospatial conceptualization is similarly affected, which reflects problems in the posterior brain (i.e., parietal and occipital lobes). Memory declines in DLB and PDD, but less than in Alzheimer’s disease. Fluctuations in mental clarity are often noted in these Lewy disorders, where near-normal thinking may be followed hours later by confusion. In Chapter 4, the process of diagnosing DLB and PDD was also discussed. Before clinicians consider such a diagnosis, however, they must be certain that they have not overlooked any other treatable causes or contributors. Sometimes the DLB or PDD diagnosis is correct but the dementia is exacerbated by some other factor. In this chapter, those factors and the appropriate workup are considered. One should not arrive at the final diagnosis of a neurodegenerative dementia before considering treatable factors, including medical conditions, brain lesions (e.g., bleeds), and medication effects. This is especially relevant if there has been a rapid decline or recent onset. Prescription drugs are a common cause of cognitive impairment. Before ordering tests, it is appropriate to go over all medications that the patient is taking. Commonly prescribed drugs that can impair cognition include those shown in Table 12.1. This is not an exhaustive list. The primary clinician should decide what, if any, medication should be eliminated.
Longevity factor klotho and resistance to cognitive deficits in a transgenic mouse model and in individuals with Parkinson’s disease
