During the past few years there is an ethical debate about neurological disease entities that are characterised by a) prolongation of life owing to medical treatment, b) limited chances of cure, and c) impaired to unbearable life quality: akinetic mutism, vegetative state ("Wachltoma", apallic syndrome), and locked-in syndrome. These are compared to typical coma and brain death. According to Gerstenbrand (1967) [34] the vegetative state is differentiated into the transitional state following typical coma, the variations of typical and incomplete vegetative state, the remission state and the "Durchgangssyndrom'' (characterized by preserved wakefulness with affective lability, disorientation, and amnesia). With regard to pathogenesis we differentiate posttraumatic and posthypoxic origin and variable lesions in cerebral cortex, thalamus or mesencephalic reticular formation. Uncertainty of prognosis is stressed. In respect of brain death we compare a) neocortical death, b) brain stem death, and c) whole brain death, and discuss problems of difficult delimitation and uncertainty of diagnosis. These syndromes are compared to anencephaly and hydranencephaly. Regarding the locked-in syndrome, typical, incomplete and complete (total) forms are distinguished. The differential diagnosis between the complete locked-in syndrome and brain stem death seems problematic. Difficulties in decisions limiting therapeutic effort stem from a) essentially intuitive judgement about observations, b) variability of syndromes and courses, c) uncertainty of prognosis, and d) differences in understanding and valuation throughout society. Emphasis is on a trustful and open colloquy among the persons concerned.