[Loss of motivation and frontal dysfunctions in old patients]

Loss of motivation and frontal dysfunction are frequent in old people. Motivation refers to what drives acts and relationships. The loss of motivation has some spécific characteristics from depression: loss of sens of meaning, loss of commitment for others, disinterest for daily activities. The frontal function is related to speed of acting, emotional system, anticipating of the future. All these points are altered in demotivated patients. For these reasons we assayed to analyse the possible links between loss of motivation and frontal dysfunctions.

The focus of this assay was to determine and to precise the functional links between frontal brain and loss of motivation in old people; 45 old patients cared in a day care hospital were proposed to participate to neuropsychologic evaluation. After their agreement and their family acceptation if they were demented, they were assessed by a practitioner, then by 2 different psychologists. They were evaluated for cognition (MMS), depression (Cornell's scale), apathy (Marin's scale), age and scholarships level. In a other time, they were tested with different frontal tests: Trail making A and B, Wisconsin, BREF (frontal battery of psychological tests) ana-lyse concerned speeds, number and natures of errors, habilities for matching categories. Loss of demotivation was scored on EAD scale. Statistical analysis was done with Systat 10 and Statview software.

It could be notice the significant negative links between EAD scores and the BREF scales, or with the number of categories found with the Wisconsin test. The more motivated the patients are the best results they have with their frontal tests. There are positive and significant links between EAD score and the number of errors at the Wisconsin test, and especially with repetitive errors either with this test or with BREF test. Repetitive errors and the number of errors, pointing some frontal dysfunctions are associated with a loss of motivation. Considering BREF sub-items, it could be shown the negative links between EAD scores and programmation or inhibition sub-items. All these points persist in a statistical model including pathology, cognitive levels, depression level at the Cornell's scale, age or scholarship level. We do not find a link between EAD scores and the time obtained with the Trail making test.

Loss of motivation is associated with some frontal impairment responsible for numerous errors in tasks. A good motivation of old people is associated with good frontal habilities especially in complex tasks or in programming capacities of old patients. There is no links between the speeds of tasks and the level of motivation. Motivation could be so related with orbito-frontal brain activities.