Correlation of neuropsychological indicators of child development with speech: Empirical research underpinning the national children’s health prevention programme

Introduction/Aim Psychophysiological disorders and speech pathology is one of
 the priority public health problems in the Republic of Serbia. Child?s
 growth and development proceed in a particular sequence and course,
 depending on individual physiological capacities, quality of neuromuscular
 structures and stimuli, which can be significantly affected by the
 environment. The development of speech from birth to the adult age is a
 result of the interaction of neurocognitive factors that contribute to a
 gradual attainment of phonological presentation and motor control abilities.
 The aim of the study was to examine the connection between manipulative
 manual dexterity, oral practice and lateralization with the development and
 speech in children and their potential for the development of prevention
 programs. Methods: The sample included 60 children from Belgrade of both
 sexes, aged between 5.5 and 7 years. Of these, 30 made up the experimental
 group - children with deviations in speech development (articulation
 disorders), and 30 the control group - typically developing children from
 the general population. The instruments used were the Manipulative Manual
 Dexterity Test (Lafayette), Oral Praxis Test, and part of the Test for
 assessing lateralisation (auditory, visual, and functional). Results The
 hand grip development level is statistically significantly different between
 the experimental and the control group (??=21.40, df=3, p<0.01). The
 presence of associated involuntary movements statistically significantly
 differs between the experimental and the control group examinees (??=10.58,
 df=1, p<0.01). Oral praxis statistically significantly differs between the
 experimental and the control group (t=2,01, p<0,05). Visual laterality
 statistically significantly differs (??=7.56, p<0.05) between the observed
 groups. When all predictors are taken into account, significant contribution
 to the explanation of the existence of speech pathology (articulation
 disorders) is given by the variables: Visual lateralization (OR = 0.38; 95%
 CI = 0.179-0.832; p = 0.015) and the level of hand grip development (OR =
 0.23; 95% CI = 0.082-0.699; p = 0.009). Conclusion: The hand grip
 development level and visual laterality are worse in children with speech
 (articulation) impairment and developmental deviations. It is these
 indicators of child development that should be used as a guide in designing
 the National programmes for developmental assessment and prevention in the
 child healthcare system.


Introduction
Most activities in the first seven years of life are part of one process of organising nerve impulses in the nervous system. Nerve impulses arise as a result of the direct influence of stimuli. As the child experiences stimuli during its life, learning how to organise them in the brain and discovering what each of them means, it learns how to focus its attention on a particular one, disregarding all the others. Additionally, by organising the stimuli, the child gains control over its perceptual experiences. Nerve impulses must pass through two or more neurons to shape a sensory experience, a motor response, or an opinion. The more complex the functioning, the more neurons become involved in the message transmission. The nervous system of each human being operates in a particular, distinct manner (1).
The function of neurons is determined by the localisation and a series of other circumstances throughout development. What is one of the basic postulates of development is that functionally higher parts develop under the influence of lower parts Each new connection adds another element to the sensory perception and motor ability of a child. The more neural connections, the more capable the child is of learning (1).
Psychomotor activities with exposure to various stimuli (that stir different senses eliciting thus psychomotor response) are the stimulating factors that promote maturation of the nervous system. Growth and development are interrelated but not necessarily interdependent.
Growth can be defined as a combination of increases in both number and size of cells.
Development is the increase in the complexity of an organism due to nervous system maturation. A child can develop normally but have a delay in growth and vice versa.
Growth can be measured precisely but presenting the measurement of development in numbers is much more difficult and almost impossible (3). Development means synchronised motor, intellectual, and emotional maturation. When we assess development, we can reduce this assessment to four major areas: gross motor skills (basic motor movements), fine motor skills (differentiated motor movements), speech and language, and social development.
Speech development cannot be observed solely through biological development as is, for example, the case with walking, because, once neurological basis becomes mature, a child gradually, by itself, starts walking, which is genetically programmed, while it will never occur with speech however predisposed the child is to that function.
The reason is that speech originates exclusively from the biolinguistic conjunction, that is, one of neurobiological potential and verbal social environment. Development of speech from birth to the adult age is the result of the interaction of neurocognitive factors that lead to a gradual acquisition of the abilities of phonological presentation and motor control in the presence of a range of physical and physiological changes in the morphology of the articulation system (4). Given the dynamics of growth and development, as well as the plasticity of the nervous system, a preschool-age child is particularly susceptible to the overall influences that are, in that period, the most enduring and efficient.
It stands as an obligation of every severe society to ensure in the best possible way the timely assessment of the psychophysiological development of every child, from its birth. Early detection of any, even the minimal, developmental disability should be a signal for a thorough monitoring and timely undertaking of the preventive and therapeutic stimulation of development. formulating and implementing government policies. In addition to this, they have an obligation to devote their entire capacities for the purpose of achieving public interest (9).
The aim of the study was to examine the connection between manipulative manual dexterity, oral practice and lateralization with the development and speech (articulation) in children and their potential for the development of prevention programs.

Methods
The research is organised as a quasi-experiment with two observed groups. It Results obtained from the research were statistically processed by the appropriate selection of statistical methods. Statistical data processing was performed using the software SPSS ver. 20 (Statistical Package for the Social Sciences). Of the descriptive statistics measures, we used arithmetic mean with the associated standard deviation, as well as the minimum and the maximum. We also used frequency and percent. The Chi-square test was used to examine the relationship between two categorical variables, then t-test for large independent samples, as well as univariate logistic regression and multivariate regression analysis.

Results
This research involved children of ages from 5.5 to 7 years. There were 60 participants, 36 of which were male and 24 female, divided into two groups. As this is a prospective cross-sectional study, the structure of the sample by gender reflects the numerical representation of the groups in the population as well. In this way a larger number of participants within the experimental group are boys (76.7%), while a larger number of girls are within the control group (56.7%) (Figure1.) The result shows that articulation speech disorders are more common in boys than in girls, as shown by other studies (10,11,12). The average age of sample participants in the E group was M=6.07+-0.5 years, and in the C group M=6.34+-0.46.
The Manipulative Manual Dexterity Test showed that the hand dominance, the hand grip evolution level and the presence of involuntary movements were statistically significant different between the examinees of the E and C groups on both trials. In the hand dominance subtest in both trials, right -handers were dominant in both groups with 60% frequency. However, there were more left-handers (40%) in the C group than in the E group (23.3%).
The hand grip evolution level showed a statistically significant difference between the E and C groups (χ² = 21.40, df = 3, p <0.01). In the C group, most are those with a group -grip with three fingers (50%) and those with a pincher grip (46.7%), while in the E group, those examinees whose hand grip is with four fingers (36,7%) and three fingers (40%) are dominant. The presence of involuntary movements are significantly different in the subjects of the E and C groups (χ² = 10.58, df = 1, p <0.01).
In the second trial, there was a statistically significant difference in the hand grip development level (χ² = 21.40, df = 3, p <0.01). Also, on the presence of involuntary movements subtest, the inverse results were identical to the first trial (χ² = 10.58, df = 1, p <0.01). The results obtained from the tests were summarised and the analysis conducted of the differences between the E and the C group on three items. Statistically significant differences were found on all three items: hand dominance (χ²=6.31, df=2, p<0.05), hand grip development level (χ²=20.25, df=3, p<0.01) and presence of involuntary movements (χ²=12.00, df=1, p<0.01) (Figure 2).
The score on the Oral Praxis Test was obtained by adding the movements that are possible, ie. where they exist. The results of the Oral Praxis Test show a statistically significant difference between the E and the C group regarding the overall test score With the lateralization assessment, we examined: Hands use lateralization, Visual lateralization and Auditory lateralization. A statistically significant difference between the E and C groups exists on the subtest Visual lateralization (χ² = 9.32, p <0.01). The largest number of subjects in the C group belonged to the group with right lateralization (83,3%), while in the E group (36,7%) subjects belong to the group with left lateralization and 13,3% of them to the group ambidextrous. The Figure 3. shows that both groups are predominantly right lateralised regarding Hand use lateralisation.
By careful analysis, we can observe that the C group has more functionally left-handed (6.7%) compared to the E group (3.3%), with the number of the ambidextrous also being higher in the E group (13.3%) than in the C group (3.3%). On the subtest Auditory lateralization both groups are predominantly right lateralised, but the number of the ambidextrous subjects is higher in E group (16,7%) (Table 3).

Discussion
The age of examinees for purposes of this research is selected according to the opinion that in that age children reach a certain degree of maturity of motor, speech, and social abilities. Timely and appropriate assessment of these abilities can point to potential deviations and deficits in the child"s development. In order for a child to become fully developed, it must reach a certain degree of maturity of the nervous system, which allows it to connect with the external world (10). Each stage of child development is characterised by certain abilities that constitute the preparatory "elements" and a base for a more complex and mature development. Psychomotor ability of hands is essential to organising ways to exist in the social field. Its organisation indicates the development degree of speech, intelligence, opinion, and feelings. The results of the Manipulative Manual Dexterity Test (Lafayette) show that the first test records a statistically significant difference on the item "hand dominance", the right-handers being dominant in both groups with 60% prevalence in each.
However, the C group records more left-handers (40%) than the E group (23.3%). The E group records 16.7% ambidextrous children, showing that this group has considerably more children without differentiated lateralisation, which indicates slow maturation of the structures and functions that determine movement lateralisation. While around 40% of children aged between 4 and 5 are weakly lateralised, this percentage drops to about 30% among those aged between 5 and 7 (11). The hand grip development level is another item recording a statistically significant difference between the E and the C group. More dominant in the E group are those with four-finger and three-finger grip, while in the C group, those with three-finger (tripod) grip and pincer grip prevail. The presence of involuntary movements statistically significantly differs between the E and the C group examinees. These movements are not recorded in the C group; however, they are found in 33,3 % of examinees of the E group. In the second test, there is a statistically significant difference in the hand grip development level. The results show us that hand grip is better developed among the C group examinees compared to the E group examinees. In a hierarchical development, a child first acquires simpler manipulative hand movements, such as palmar grip, that eventually evolve into the pincer grip. In the C group, we had considerably more of those using the pincer grip, which involves the ability of proper grip (appropriate to the examined age group), characterised by thumb opposition and meaningful coordination of movements of hand segments in performing manipulative activities (12,13). Statistical difference was also found on the item "presence of involuntary movements". The lower prevalence of involuntary movements among the examinees of the C group relative to the E group indicates better neuromaturation of CNS within the C group. The obtained results show that differentiated hand motor patterns are better developed in typically developing children, that is, ones in the C group. Given that differentiated hand motor patterns hierarchically develop before oral motor patterns (responsible for oral praxis), some deficits in speech development can be expected and predicted in children without differentiated hand motor movements at certain age (14). The results of the Oral Praxis Test show a statistically significant difference between the E and the C group, which shows us that children with some developmental speech (articulation) deviations have a less developed oral praxis relative to typically developing children (15). In the development and maturation of orofacial musculature, the first acts to evolve are swallowing, sucking, and chewing. Deficits in these functions at certain stages of development are the first indication of poor oral praxis (16,17).
Lateralisation assessment has revealed a statistically significant difference between the E and the C group concerning visual laterality. Figure 3. shows a higher number of examinees with non-differentiated laterality in the E group and indicate the existence of disharmonic laterality, concurrently indicating the slow maturation of certain functions among these examinees (18). From further processing of research results we found the following as the predictors of the existence of speech pathology (articulation disorders): hand dominance, hand grip development level, oral praxis and visual laterality. After conducting a univariate regression analysis, the variables that proved to be statistically significant predictors in the explanation of the speech (articulation) disorders entered the multivariate regression analysis. The results showed that poorer visual lateralization increased the chance that the subject would have speech pathology by 62%, and that griping with the whole hand and with four fingers increased the chance of developing speech (articulation) pathology by 77%. These two variables accurately classify 80% of participants.
These findings show that it is the inability to learn or immaturity of any of these functions that can provide a timely indication of the delays in child development and predict future deficits in the development of speech as a more complex function. It is crucial to timely recognise disharmony and to include the child in stimulating treatments to prevent potential disorders to any extent. All obtained results point to the necessity of preventive action, which should be conducted at the level of primary health care with a view to timely preventing the occurrence of developmental disabilities. The psychophysiological growth and development of a child must be appropriate to its age; if not synchronised, whether from objective or subjective reasons, it creates disharmony in the child"s development, which can particularly be observed in speech development.
With a view to developing the health care system in the Republic of Serbia, special consideration is given to the protection, improvement, and promotion of health of the youngest generation. Determination of causes of disorders as well as early detection and prevention are the main aim of all health systems, including both that of our country and those of Europe and the rest of the world. For this exact reason it is necessary to develop a detailed and precise Programme for preventive child protection at the national level, which would be implemented through the level of primary health care, by delivery. In accordance with the objectives of the proposed National Programme, the strategy has been defined for information, education, communication, and social mobilisation, along with the action plan for its implementation, time frames, and entities responsible for the implementation of the set activities in primary health care.
The key limitation of this study is small sample size. These data can be the basis for future research in order to develop preventive and therapeutic programs.

Conclusion
The research results show that visual lateralization and the level of hand grip are worse in children with impaired speech (articulation) compared to typically developing children. The poorer visual lateralization increased the chance that the subject would have speech pathology by 62%, and that griping with the whole hand and with four fingers increased the chance of developing speech-articulation pathology by 77%. The ability of fine motor coordination, visuomotor control, and differentiated lateralisation are all associated with the development of speech and higher nervous activities, which means that they can be helpful in assessing the child"s developmental level and maturity. It is this fact that should be considered in creating the assessment and prevention programmes in the health care system.   Figure 3. The assessment of lateralisation -difference between the E and C group