Introduction
This study was conducted by Frenkel S. and B. Bourdin. They carried out this research to assess the various memory sytems (short term) from a developmental view of patients of Down’s syndrome (DS). The study compared the patients’ performance to those of normal individuals of similar mental age. Down’s syndrome is the most common cause of Intellectual Disability (ID). Down’s syndrome, also named Trisomy 21, is a genetic condition which is caused by the partial or full presence of an additional 21st chromosome (Frenkel and Bourdin, 2009). The extra chromosomal material delays the development of a child physically and mentally. Down’s syndrome causes dysfunction in cognitive abilities of the patient. The patients face mild to severe learning complications and difficulties throughout their life. It may also impair physical development and the patients have a distinctive set of facial features. The patients have a chin which is abnormally small (microgenia) and a strangely round face (macroglossia). They also have a large or protruding tongue, and an almond-shaped eyes caused by an eyefold. In addition, the patients have shorter limbs and poor muscle tone. The degree of impairment may vary from mild to moderate (Medicine Net, 2011).
A patient with Down’s syndrome exhibits a unique developmental profile (Lipmann et al. 1999). They demonstrate impaired levels of expressive language and short term memory (STM). However, non verbal abilities function well with cognitive functioning. Many research studies have concentrated on verbal STM development. It is well known that patients have impairments in the verbal STM capacities. It seems that non-verbal STM is a well preserved and even strong ability of the DS patients. The study sought to determine the specificity and extent of the impairments in verbal STM (Frenkel and Bourdin, 2009). The research study therefore allowed the scientists to assess both short term memory from a developmental view and to compare these results to those obtained from normal individuals of the same age. They have not fully explored the development of other systems of memory. For example, there are few studies exploring visual-spatial ID. This research study therefore explored different aspects of STM.
Methods
The participants in this study were 108 teenagers and children from France. They were divided into two groups of fifty four. One group was that of patient’s of Down’s syndrome and the other was of normally developing children and teenagers. In the study, participants with Down’s syndrome were matched with normal participants based on cognitive developmental age. They were also matched based on socioeconomic and sex criteria. This matching was confirmed by ANOVA (analysis of variance).
The candidates were subjected to various tasks: Auditory Word Span Task (AWST), Visual Patterns Task (VPT) and CBT (Corsi Blocks Task). For each task, the participants were exposed to training to familiarize participants with the task. This was also done to make sure that each participant clearly comprehended the instructions. For each level of difficulty, there were a total of 3 trials. The sequence length was made longer with every successful attempt at a task. AWST was comprised of monosyllabic words which were familiar and put in lists. Within a list, certain words were different, either phonologically or semantically. VPT was comprised of patterns of squares where half were filled in. Participants were required to locate and identify the missing square CBT was composed on a board with nine slots which were asymmetrical and had a square block. These blocks were displayed in different sequential orders to the participants (Frenkel and Bourdin, 2009).
Results
Comparisons were made based on the performance of the test groups. The tasks (AWST, CBT and VPT) were analyzed and compared for:
- Diagnostic- normal v down’s syndrome
- Sex- male v female
- Developmental age
The sex factor was found to have no significant effect with another factor. This means that normal children performed better than DS patients. For the AWST parameter, DS patients performed lower than normal patients. DS patients had a spatio-sequential span which was higher among the lower developmental ages. Visual span did not record any significant differences.
Significance
The data which was derived from various STM systems did not confirm that there is a deceleration or decrease of the rate of development. In intellectual function, memory is very important in cognitive ability. It is important to identify the specificities of development in Down’s syndrome patients. This helps in understanding the special needs of the children. This will ensure that remedial programs which target their needs are able to address their specific issues (Medicine Net, 2011).
The study determined that normal children did not show a higher developmental rate than DS patients. The results affirmed that while DS patients have slower cognitive abilities, their developmental process was qualitatively different. Patients with DS showed a unique pattern of performance of their memory and their development.
References
Lippman A, Miriam Kupperman, James D Goldberg, Robert F Nease Jr., & A Eugene Washington. (1999). Prenatal Diagnosis / Kuppermann et al. respond. American Journal of Public Health, 89(10), 1592-3
Babak Khoshnood, Catherine De Vigan, Véronique Vodovar, Gérard Bréart, & et al. (2006). Advances in Medical Technology and Creation of Disparities: The Case of Down Syndrome. American Journal of Public Health, 96(12), 2139-44.
Frenkel S. and Bourdin B. (2009). Verbal, Visual and Spatio-sequential short –term memory: Assessment of the Storage Capacities of Children and Teenagers with Down’s syndrome. Journal of Intellectual Disability Research 53 (2): 152-160.
Medicine Net (2011). Down’s Syndrome. Available at http://www.medicinenet.com/down_syndrome/page4.htm#cognitive
National Institute of Child Health and Human Development (2011). Down’s Syndrome. Available at http://www.nlm.nih.gov/medlineplus/downsyndrome.html
