Utility of Developmental Reflexes in the Differential Diagnosis and Prognosis of Incontinence in Alzheimer's Disease

Four developmental reflexes, the tactile suck reflex, the palmar and plantar grasp reflexes, and the plantar extensor reflex, were examined in 784 individuals, including healthy elderly, cognitively and functionally mildly impaired individuals, and patients with Alzheimer's disease (AD) in all stages of clinical severity. The study population was classified into six categories of increasingly impaired functional performance, and prevalence of the four individual reflexes and of a summary reflex measure, consisting of a combination of these four reflexes, was determined for each category. Prevalence of all five reflex measures was more than six times higher for those categories that comprised only permanently doubly incontinent patients as compared to those categories that comprised only continent individuals (P < .001). Frequency of developmental reflexes rose sharply with the onset of progressive incontinence. Since the return of these reflexes in AD is associated with severe cortical dysfunction, it is concluded that these developmental reflexes are useful in differentiating incontinence of cortical origin from incontinence resulting from potentially reversible causes.