Abnormalities in the orienting response in senile dementia

Forty-five female patients with the diagnosis of senile dementia and subdivided according to degree of mental deterioration were paged over a loudspeaker placed directly to the right or to the left of the patient. In the most demented subgroup, motor and/or verbal orienting responses often failed to appear. A turn towards the loudspeaker used was more often evoked in the least deteriorated subgroups. Turning in inadequate directions is tentatively explained in terms of dysfunctions within the auditory system and with reference to the disorientation of the patients. Twenty of the senile dementia patients were also compared with 20 healthy aged persons concerning habituation of orienting responses when exposed to 15 stimulations with intermittent light. The demented patients did not habituate significantly whereas control subjects did. The defective habituation of the patients is tentatively explained in terms of their memory disturbances and low capacity to interpret sensory data.