Efficacy and Safety of Talsaclidine in Patients With Mild to Moderate Dementia of Alzheimer Type

Inclusion Criteria: * Male or female patient, age: over 40 years (lower age if genetic Dementia of Alzheimer Type (DAT) is documented. Patients over 85 years need to be in a clinically stable state (investigator's judgement) * Patient's educational level is \> 4 years * Patient is able to understand the patient information and give informed consent * Patient has given written informed consent in accordance with Good Clinical Practice and local legislation * Patient has a non-demented relative or care giver who is willing to support the clinical trial; his/her written informed consent is optional * Body weight: within +/- 30% of normal weight (Broca index) * Diagnosis of DAT by the National Institute of Neurological and communicative Disorders-Alzheimer's Disease and Related Disorder Association (NINCDS-ADRDA) criteria * MMS-score 10 - 24 inclusive * Rosen ischemia score is lower or equal to two * Patient is able to complete the trial examinations, to hear, speak, read and write in a basic way and primary sensorial functions are intact Exclusion Criteria: * Any dementia of vascular genesis (excluded by Rosen ischemia score \> 2) * Magnetic Resonance Imaging (MRI) or Computer Tomogram (CT) (more recent than 12 months; if a MRI of CT recording is performed more than 12 months before study entry, it must be repeated) findings make the diagnosis of DAT unlikely * Any stroke history * All secondary dementia (exclusion diagnosis defined by the NINCDS-ADRDA criteria) as a late complication of: * Cranio-cerebral trauma * Intoxication (incl. history of alcohol and drug abuse) * Cerebral infections (e.g. neurosyphilis) * Thyroid dysfunction * Cerebral dysfunction due to metabolic disorders (e.g. unstable thyroid dysfunction, or unstable insulin-dependent diabetes mellitus with hypo-/hyper-glycemic episodes) * Deficiency of vitamin B12 or folic acid as a reason of dementia * Brain tumour (A patient with an incidental tumour found on CT not felt to be clinically relevant may be included, i.e.: meningioma) * Down's syndrome, Parkinsonism, Huntington's chorea * Multiple sclerosis * Major depression defined by the Hamilton Depression Rating Scale (HAMD) 17 item scale (≥ 16) * Depressive pseudo dementia * Mental retardation * Hydrocephalus * Epilepsy * Endogenous psychoses (schizophrenia) * Untreated or non-compensated hypertension (Blood Pressure systolic \> 180 and/or diastolic \> 110 mmHg) * Hypertension being treated with reserpine, clonidine or β-blockers (these cases have to be adjusted to therapy with e.g. calcium antagonists 4 weeks before start of treatment) * Severe heart failure (NYHA: III and IV) * Arrhythmias (Lown: II-IV, Electrocardiogram \> 30 ventricular extrasystoles/hour, multifocal or multiform and repetitive forms of ventricular extrasystoles) * Bronchial asthma with phases of exacerbation or inducible by aspirin or other Nonsteroidal anti-inflammatory drugs * Severe diabetes mellitus: insulin dependent and not stabilised (patient with an HbA1c in normal range, clinically stable diabetes and any case of insulin dose ≤ 0.5 UI/kg/day may be included), or other metabolic diseases * Renal insufficiency: calculated creatinine clearance is less than 60 ml/min * Acute hepatic disorder (liver enzymes above 50 % upper normal limit) * Chronic hepatitis within the last two years (positive hepatitis titer, Hepatitis A Virus, Hepatitis B Virus, Hepatitis C Virus, cytomegalovirus, Epstein-Barr virus or abnormal immunological values (positive immunoglobulin M(IgM)/IgG) are allowed if all liver enzymes are within the normal range) * Recent history of liver disease (2 years) including drug intoxication (e.g. narcotics, cytostatics etc.) * Patients with obvious symptoms of dehydration * History of drug or alcohol abuse or dependence on other hepatotoxic agents (if a patient is permanently hospitalised and a drug screen performed at the beginning of hospitalisation, no additional drug screen is necessary) * Neoplasm currently active or likely to recur (except basal cell carcinoma) * Participation in another clinical trial within the last four weeks and re-entering from this or a previous talsaclidine trial * Pregnant and lactating woman, woman with childbearing potential not using an approved method of contraception * Insufficient compliance: in the investigator's opinion the patient or family is unable to comply with the protocol requirements