People with DLB characteristically experience dramatic swings in their level of alertness, fluctuating from clarity to confusion, often in a short period of time. Visual hallucinations are common in DLB, typically of people and animals, which are vivid. Although they may have other Parkinsonian symptoms, the tremor associated with PD is not always present. Because DLB, AD and PD share so many symptoms, diagnosis of DLB can be difficult and requires an experienced specialist e.g. in old age psychiatry or neurology. Accurate diagnosis is essential for successful treatment.