Medicine And Biopharmaceutical - Proceedings Of The 2015 International Conference

Proceedings of the 2015 International Conference

Masahide Takahashi

• Publisher: WSPC
• Year: 2016
• eBook ISBN: 9789814719827
• Topic: Biological Sciences
• Subtopic: Science General
• Index: Biological Sciences

This book provides an all-embracing review of each and every author's study on the related topics and areas. For instance, some author's study on Chinese Medicine, and some other researchers' survey on biomedical engineering. Moreover, there are also papers that focus on information based bioinformatics, pharmacy and medicinal chemistry and biopharmaceutical technology.

This book provides an all-embracing review of each and every author's study on the related topics and areas. For instance, some author's study on Chinese Medicine, and some other researchers' survey on biomedical engineering. Moreover, there are also papers that focus on information based bioinformatics, pharmacy and medicinal chemistry and biopharmaceutical technology.

Readership: Pharmaceutical researchers and health professionals.
Key Features:

• This book contains a large range of topics, from medicine and medical science, bioinformatics to biomedical engineering and biological pharmaceutical. It is an invaluable source for other researchers, engineers, and academicians, as well as industrial professionals
• It welcomes authors from universities, institutions, labs, etc., which means that it provides different information according to different readers and different needs
• This book will not only serve as a reference to the readers, but also an important tool for the authors to re-examine their researchers by comparing them to other similar ones shown in other papers

Session 1: Medical Science

Memory Updating Deficit in Attention Deficit Hyperactivity Disorder (ADHD) Children

Wei Zhang^a, Li Fan^b, and Ye-Ping Jiang

School of Psychology, Central China Normal University, Wuhan, 430079, China
E-mail: ^a[email protected], ^b[email protected]

The aim of the present study was to explore the mechanism of verbal working memory deficit of Attention Deficit Hyperactivity Disorder (ADHD). Memory updating of verbal working memory was assessed by presenting 21 ADHD children and 17 control children age 7 to 12 during a verbal n-back task. The ADHD group performed worse than the NC group in the memory updating level 1 and level 2, but no difference in level 0. Effect sizes were 1.31 and 1.63; both were on a very high level. Additionally, with the increase of memory updating difficulties, the ADHD group showed a greater decline than the NC group. The effect size of 1.54 is on a very high level. ADHD children show deficits in the advanced process of verbal working memory, when engaged in memory updating. Research has theoretical and clinical implications for children with ADHD.

1.INTRODUCTION

Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common neuropsychiatric disorders of childhood. The core behavioral symptoms of ADHD are inappropriate patterns of inattentiveness, impulsivity, and hyperactivity[1].

Working-memory deficit was a significant symptom of learning disabilities and mood disorders. ‘Working memory’ refers to the ability to hold and manipulate information or rules in mind[2]. Verbal working memory contains phonological loop and the central executive (CE). The phonological loop is responsible for the encoding of verbal information and repeating it, which is a basic process. The CE function is responsible for information operations, including the timely updating of information, control of attention, etc.

For example, verbal working memory deficit in children with ADHD was found in the digit span task[3,4]. When performance was broken down into Forward versus Backward digit span, findings showed that children with ADHD performed worse than other children on Backward but not Forward digit span[5]. Although children with ADHD were able to repeat as many digits as healthy children in forward order, they had trouble repeating digits in backward order. Children with schizophrenia had smaller spans in both the Forward and Backward conditions. Forward Digit Span made demands primarily on the verbal buffers and rehearsal processes, whereas Backward Digit Span should rely on the central executive. The children performed a verbal distractor task during the delay to prevent verbal rehearsal. Thus, ADHD children’s ability in phonological coding and rehearsal mechanisms may not exhibit obvious obstacles, but the problem in central executive did exist. Interestingly, Karatekin apparently found that ‘ADHD does not have generalized impairments in working memory, rehearsal verbal and spatial information in the same manner as healthy children’, but found children with ADHD may have an impairment in the central executive component of working memory, which controls the ability to divide attention between two tasks[6]. The results showed that, compared to normal children in the double digit span task conditions, the response time of children with ADHD was clearly longer than the normal control, while there was no significant difference between the two groups in dual tasks on simple reaction time. In fact, Karatekin simply confirmed the central executive function to dual-task processing capacity, in which there are obvious limitations. The ability to divide attention assessed in the dual task is just a small aspect of CE, it is not representative. If ADHD children showed deficiencies in dual-task operation, on the one hand, this may be due to ADHD children’s inability to effectively maintain the mission objectives. It was also possible that ADHD children cannot effectively allocate attention resources or cannot quickly shift attention between the dual tasks. But, this did not represent all the characteristics of the central executive function.

Some studies also found that ADHD children’s verbal and spatial working memory was normal. For example, when comparing ADHD and language impairment of working memory, Cohen found that the verbal and spatial working memory in language impairment patients were more serious than ADHD, while working memory deficit in patients with ADHD was not serious[7]. It showed that ADHD children with SLI scored significantly lower than those without SLI and normal children, on verbal working memory measures only. Both ADHD groups performed normally on spatial working memory measures. It was concluded that working memory deficits were not a specific characteristic of ADHD but were associated with language impairments. To the contrary, Kofler suggested that ADHD individuals had deficits in working memory encoding, rehearsal and central executive[6]. There was a functional relationship between working memory and children’s attentive behavior, and these working memory problems contributed to the inattentive behavior in school and in other settings. All children’s attentive behavior decreased when they were required to process a greater number of phonological and visuospatial stimuli, and the magnitude of these changes was significantly greater for children with ADHD relative to typically developing children. Children with ADHD were significantly less attentive under even the lowest working memory set size conditions, and these rates were nearly identical to those observed in regular education classroom settings based on a recent meta-analytic review. Further studies have found that the central executive processing results can explain the dramatic decline in children with ADHD, and the deficit in non-central executive processing exceeds storage/rehearsal capacity.

To summarize, it is not difficult to find that the focus of debate is whether children with ADHD shows a clear verbal working memory deficits, and if so, whether deficiencies in specific underlying mechanisms or processes which are unique to a particular disorder such as ADHD are central to child psychopathology theory development. However, previous researchers usually have used working memory span tasks to assess working memory capacity of ADHD children. These tasks involve the participation of a variety of cognitive processing, including verbal and spatial encoding, rehearsal and the participation of a variety of central executive functions. Specific processing mechanisms are not exactly identical in different working memory tasks. Therefore, the conclusions of various studies are, understandably, inconsistent. Although ADHD children show the weakness of working memory capacity, its substantial mechanism is still not clear. This is because it is still not enough to assess central executive processing of ADHD children only, which is particularly necessary.

The n-back paradigm was often used to examine an updating process of a running memory. Subjects were presented with lists of varying lengths from three to eight consonants. After each list, a recall of the three most recent list items was required. In this task, the length of the sequence of items to be maintained active in working memory was held constant. At the same time, subjects in each step after position 3 had to delete the first element in the current three item list, and to add the newly presented item to the end of this list. From interference patterns with different secondary tasks it was concluded that besides activity of the verbal loop system, central executive functions are necessary for this memory updating.

As task difficulty increases, the degree of central executive involvement will also increase; the deficits of memory updating mechanism can be explored in the basic and advanced processing by varying the difficulty of the task. The logic is that with the increased difficulty of updating, if ADHD scores declined more than normal subjects, it indicated the ADHD children’s difficulties in memory updating, when n=0. In the condition where memory update operations were not involved, if ADHD children still got worse scores than normal subjects, it reflected the basic defects in verbal working memory processing. Traditional n-back task was designed based on normal adults and children, not suitable for children with disabilities. To reduce the difficulties, Kiss made a modification of Morris and Jones’ running memory procedure[8]. The approach was to shorten the series and split it into many independent trials, which was deemed more suitable for children with disabilities. This modified version will be employed to examine verbal working memory capacity of children with ADHD in this study.

2.METHOD

2.1.Participants

Participants comprised 21 ADHD children and 17 control children age 7 to 12 years, matched on age (F= 0.877, P>0.05), and IQ (F= 2.292, P>0.05) (see Table 1).

ADHD children were recruited by a Children’s Learning Training Center through community resources. To ensure a qualitatively high diagnostic procedure, the families of all participants went through a two-stage process before being included in the study, and the children were administered an IQ test (Raven’s Standard Progressive Matrices: Chinese Revised version.). In the RSPM, children scoring lower than 25% were excluded as were comorbidities of mood disorder, psychosis, mania, major depression, substance abuse, pervasive developmental disorders and receptive language impairments. The control children were recruited from an ordinary primary. The assessment included the diagnostic criteria, that is, the score was 3 or less on the two dimensions of the DSM-IV criteria[1], and children were not associated with significant psychological disorders. The study was approved by the Ethics Committee of Central China Normal University.

Table 1. Characteristic of the ADHD and Control Group

	ADHD	Control
N	21	17
M : F	15:6	12:5
Age
Mean	8.60	8.50
SD	1.50	1.02
IQ
Mean (%)	63.8	67.5
SD	11.5	12.3
CPRS
Mean	13.9	5.6
SD	2.3	1.8

Note: M = male; F = female; CPRS = Conners' Parent Rating Scales: Chinese Revised short version.

2.2.Experimental task

The procedure started with letters that was presented in the center of the screen. The subjects were asked to judge whether the probe stimuli was the...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Preface
• Committees
• Contents
• Session 1: Medical Science
• Session 2: Biomedical Engineering and Biotechnology
• Session 3: Biological Pharmaceutical
• Session 4: Food Hygiene, Environment and Human Health