For every three people currently living in Western countries, at least one will develop dementia, stroke or both [1,2]. Stroke is the leading cause of physical disability in adults: of one million inhabitants, 2400 people have a stroke every year, of whom more than 50% will die or become dependent 1 year later [3]. Dependency after stroke is often due to dementia [4]. Even in stroke survivors who are independent, slight cognitive or behavioral changes may have consequences for familial and professional activities [5]. Dementia is also frequent in Western countries, especially after the age of 75 years, where its prevalence is close to 18% [6]. About 40% of demented people live in an institution, and among institutionalized residents two-thirds are demented [6]. Therefore, the economic burden of dementia is important.

Stroke and dementia are both frequent and their relationship is more complex than being just a coexistence of two frequent disorders. Besides being a potential cause of dementia, and a factor that negatively influences the time-course of Alzheimer's disease (AD), stroke also shares many risk factors with AD, such as increasing age, arterial hypertension and ApoE4 genotype [7]. The prevalence of stroke and of dementia is likely to increase in the coming years, because of the decline in mortality after stroke [8] and the aging of Western populations [9]. Therefore, the burden of stroke-related dementia is also likely to increase in the future [5].

Introduction

Stroke is a major public health issue because of its high frequency, the risk of death and residual physical cognitive or behavioral impairments, and the risk of recurrent vascular events that may be cerebral or cardiac [1–3]. Although strokes occur at a mean age of 75 years in Western countries [4–6], they may also occur in younger patients, and even in children [4–7]. Most strokes occurring in young patients are ischemic in origin. They account for from 2 to 12% of all strokes, depending on whether figures are provided from community- or hospital-based data [8, 9].

The main specificities of ischemic strokes in young patients are their causes, their outcome and the possibility of occurring during pregnancy. These specificities may influence the management of patients. Therapeutic options should therefore take into account the presumed cause, the natural history of the disease and the long life expectancy. The clinical deficits and acute management have no specificity in young people, and will therefore not be addressed.

Epidemiology

Figures depend on the definition of “young”. Three upper thresholds can be found in the literature, at 30, 45 and 55 years of age. The most frequently used upper age limit is 45 years. It constitutes a good compromise between an age category where common causes of cerebral ischemia, such as atheroma, atrial fibrillation and lipohyalinosis, are very rare, and on the other hand a disorder that is not too rare. The incidence of ischemic strokes increases with age even in young people: most young people with stroke are between 40 and 45 years of age [7].

Main characteristics of delirium and confusional state

Delirium or acute confusional state (ACS) is a mental disorder characterized by acute onset, altered level of consciousness, fluctuating course, and disturbances in orientation, memory, thought, and behavior (Lipowski, 1990). This condition is frequent in stroke patients, although stroke is a rare cause of ACS. Many predisposing factors have been identified. Stroke per se may, however, induce ACS. The occurrence of this behavioral disturbance adversely influences outcome in stroke patients. However, no specific treatment is available.

ACS is an acute, transient disorder of consciousness and cognition with fluctuating intensity. The symptoms of delirium are wide ranging, and although they are non-specific, their abrupt or rapid onset and their fluctuating nature is highly characteristic and is a valuable diagnostic tool. The main feature of delirium is disordered attention with difficulties in focusing and sustaining attention on one stimulus and difficulties in shifting attention to new external stimuli: attention wanders, perseverations may be observed. Attention disturbances are not isolated and examination will reveal abnormalities of thinking, perception, and memory. The change in cognition includes impaired memory, language (anomia, incoherent speech, aphasia, agraphia), disorientation to time and place and visuospatial dysfunction. Perception disturbances may also be present with illusions, hallucinations, or delusions. Sleep–wake abnormalities are frequent with daytime sleepiness and reduced and fragmented sleep during the night with nocturnal agitation, shouting, and aggressivity. Many individuals are restless and hyperactive while others are lethargic.

General characteristics of akinetic mutism

Neuropsychological deficits are of major importance in stroke patients: they are frequent, have a major diagnostic value as they may be the only clinical manifestation of stroke, require a specific management, and are a major determinant of residual disability. This chapter will focus on the main characteristics of akinetic mutism and related disorders, which are sometimes classified as “coma-like states.”

Clinical description

The main characteristics of akinetic mutism and related disorders that may be misdiagnosed with akinetic mutism are summarized in the Key points table. All these conditions may occur after a coma of a variable length of time, and represent a favorable step between a comatose state and return to normality. The main difference between these conditions and coma is that sleep–wake cycles are present. This differentiation is important to determine the prognosis and to choose the most appropriate therapeutic strategy.

Akinetic mutism

Akinetic mutism is also called “abulia major,” and was formerly called “coma vigile.” Patients with akinetic mutism appear alert or at least wakeful, because their eyes are open and they have active gaze movements. They are mute and immobile, but they are able to follow the observer or moving objects with their eyes, to whisper a few monosyllables, and to have slow feeble voluntary movements under repetitive stimuli. The patients can answer questions, but otherwise never voluntarily start speaking. In extreme circumstances such as noxious stimuli, they can become agitated and even say appropriate words.

The association of stroke and dementia is frequent and can be seen either in the diagnostic work-up of patients attending a memory clinic, or during the follow-up of stroke patients. The terms ‘vascular dementia’ (VaD), and ‘poststroke dementia’ (PSD) are respectively used for these two different clinical situations. The term PSD includes any type of dementia occurring after a stroke, irrespective of its presumed cause (Pasquier & Leys, 1997). VaD is a dementia syndrome likely to be due to stroke lesions (Chui et al., 1992; Roman et al., 1993). VaD accounts only for a part of PSD (Tatemichi et al., 1994a, b; Pasquier & Leys, 1997) and may occur without any obvious clinical history of stroke. VaD is the second most common cause of dementia, as it accounts for 10 to 50% of the cases, depending on the geographic location, population and criteria used (Rocca et al., 1991; Hebert & Brayne, 1995). Strokes lead to a high risk of cognitive impairment and dementia (Tatemichi et al., 1992; Tatemichi et al., 1994). As vascular causes of cognitive impairment are common, and perhaps preventable, patients could benefit from therapy, early detection and accurate diagnosis of vascular cognitive impairment and VaD is a challenge (Bowler & Hachinski, 1995).

Epidemiology of poststroke dementia

Descriptive epidemiology

Prevalence

Depending upon the composition of cohorts, prevalence rates of PSD vary between 13.6% (Censori et al., 1996) and 31.8% (Pohjasvaara et al., 1997) at 3 months. A study reported a prevalence rate of 32.0% after 5 years (Bornstein et al., 1996). The prevalence of dementia is higher in stroke survivors than in matched controls (Censori et al., 1996; Pohjasvaara et al., 1997).