- Objective: In this study, we attempted to assess the impact of demographic variables such as age, gender, and grade level on verbal and non-verbal episodic learning and retention in healthy subjects. A decline in memory capacity usually occurs with age. According to many studies, particulary that of Murre, Janssen, Rouw and Meeter (2013), this decline is especially marked in episodic memory and more pronounced in non-verbal rather than verbal modality. In addition, there are differences in memory between women and men. Thus, women have greater verbal memory skills than men, who perform better in non-verbal memory. Finally, the level of education would have an effect on learning and retention capacities: Participants with a level of education ≥12 years of age have better learning and retention abilities than people with a level of education <12years
- Method: We evaluated the episodic memory of 110 control participants who were divided according to their gender and their age and level of education: 18 – 34 years (n = 47), 35 – 54 years (n = 45) and over 55 (n = 18). Each age group included men of women with a level of education of less than or equal to 12 years. To examine episodic memory, we used the Rey Auditory Verbal Learning Test (RAVLT) for the verbal modality, and it’s the equivalent for the non-verbal modality, the Aggie Figures Learning Test (AFLT). Each test was evaluated as follows: a main list of 15 drawings / words was visually presented 5 times to the subject in a fixed order and each drawing / word is presented individually. The exposure time of each drawing / word was controlled. At the end of each presentation of the list, the participant had to draw / recall the most figures / words he remembered in any order. At the end of the 5 presentations, an interference list of 15 drawings / words is presented to the participants who had to draw / recall as much memory as possible. Following this presentation, participants were asked to draw / recall as many of the possible figures from the main list as possible. Then 20 to 30 minutes after the learning and immediate recall phases, the participants made a free recall from the main list
- Results: Our results showed a decline in learning abilities as aging progresses, we found higher in non-verbal memory than in verbal memory. Indeed, people over 55 hold less information than others. In addition, regardless of age, participants have better verbal retention than nonverbal. However, no gender effect or level of study was observed in this study
- Discussion: The decline in memory abilities with age observed in our study, and in the literature, is something common. From a neuroanatomical point of view, young adults have a bigger brain volume than older people, which makes them more efficient in encoding, storing, and retrieving information immediately and delayed. Another hypothesis of this decline is the decrease in executive functions (Andrés & Van der Linden, 2000). The various tasks of our study are quite long and require in particular concentration and attention to carry out the tests in their entirety. However, it is known that executive functions also decrease with ageing, so this leads to decreased attention and concentration, leading to memory abilities that are also declining.
- Limitations : The limitations of this study are due to the small number of participants, especially for the group of people aged 55 and over but also for the group of people with a level of education of less than 12 years. This small size leads us to consider our results as preliminary. Another element which created difficulties in our study is the subjectivity of the AFLT rating.
- Perspectives: We have established baseline data on episodic memory performance in healthy participants by age, by sex and study level. These data could be used in subsequent studies to compare them to a population with drug-resistant temporal epilepsy to evaluate the impact of this pathology on memory.
Key words : Verbal and nonverbal memory, Ageing, learning abilities,
Words I have learned : Leads : pistes ; Skills : compétences ; Attempted : Tenté
References :
Murre J. M. J., Janssen S. M. J., Rouw R. & Meeter M. (2013). The rise and fall of immediate and delayed memory for verbal and visuospatial information from late childhood to late adulthood. Acta Psychlogia, 142(1), 96-107.
Andrés, P., & Van der Linden, M. (2000). Age-Related Differences in Supervisory Attentional System Functions. The Journals of Gerontology: Series B, 55(6), P373‑P380.