It is well established on the fact that regular exercise can help in treating various brain disorders such as depression, insomnia, Parkinson disease, and Alzheimer’s disease. However in case of the patients with intellectual disabilities, they lack determination to participate in any physical exercise mainly due to decreased motor nerves activity, behavioral disorder, lack of concentration and poor communication skills. Additionally, since establishing voluntarily participations and self-motivations are difficult for the intellectual disabled patients, the effectiveness of the rehabilitation treatment is also very limited. Therefore there is a need for appropriate measure to be taken for the purpose of providing interest and motivation to the intellectually disabled patients. Considering these aspects, through unique and interesting characteristics of water, aquatic exercise could maximize the effectiveness of exercise. Since embarrassment of physical disabilities can be overcome in water, patients with intellectual disabilities can actively participate in exercising [1]. Recently, as part of effective methods of improving the cognitive functions caused by the deficiency of neurotransmitters in depression, Alzheimer’s disease, stroke, and Parkinson’s disease, the CES (cranial electrotherapy stimulation) equipments are given attentions to. The CES activates on the particular neurons of the electrical current in the brain stem, increasing the production of the neurotransmitters thereby increasing the electric and chemical activations [2]. The CES can be used as non-pharmaceutical intervention method for the purpose of chronic pain syndromes such as anxiety, depression, insomnia, stress relief, headache, backache, toothache, muscle pain that are reported to be largely effective in improving anxiety and pain prior to surgery [3]. Importantly, the effect of CES is related to enhanced motion performance capability in stroke patients that can be used as a tool to enhance the effectiveness of exercise during the process of rehabilitation [4-6]. Therefore it is expected that the effect of the CES measure may enhances the cognitive function of the intellectually disabled.

On the other hand, the BDNF (brain-derived neuropathic factor), the IGF-1 (insulin-like growth factor), and the VEGF (vascular endothelial growth factor) that came into the recent spotlight, may increase the resistance on the death of the neurons cells and facilitates the production of cerebrovascular and nerve formations [7-9]. It is being reported that the signal control of the nerve formation in the hippocampus affecting BDNF, IGF-1 and VEGF, strengthens the neural plasticity, learning and memory and enhances the cognitive function [10,11]. In light of these facts, exercise of the brain with nerve disability, the CES interventions and the analysis of the BDNF, IGF-1 and VEGF could verify the rehabilitation methods and their effectiveness. Hence, in this experiment, the aquatic exercise was conducted to the mentally ill patient for the purpose of inducing interest in exercising, and the CES measures that have been known to be effective in improving cognitive function, concentration, and anxiety symptoms, were taken. Therefore the objective of this experiment is to prove the rehabilitation effect of the aquatic exercise and CES through 12 weeks of conducting aquatic exercises and by analyzing the CES measures such as cognitive function, BDNF, IGF-1, and VEGF.

In this experiment, the effect of aquatic exercise and CES measures on the changes of cognitive functions, BDNF, IGF-1, VEGF, and serotonin values were analyzed and discussed accordingly. According to the Wilson et al. [12], in relation to exercise and cognitive function, it has been reported that exercise stimulates the biochemical changes of the nerves in the brain which induce the activation of the neurotransmitters and formation of the genetics thereby affecting the proliferation of the neurons and their survival resulting in the enhancement of learning, memory and cognitive function skills. However through which mechanism that exercising affects the brain and its cognitive function remains unknown. In this experiment, the cognitive functions of the Exercise group and Exercise + CES group increased after the treatment group than before treatment. According to the Wilson et al. [12], the reduction in the cognitive function was highly correlated to the reduction of the physical functions. Salmons & Sahakian [13] showed that low concentration and attention deficiency characteristics that are common in patients with brain disabilities improved through regular exercise. Especially in the Foster et al. [14], similar result was suggested where cognitive function was enhanced through regular exercise. It has been shown that the cognitive function was greatly increased in the Exercise + CES group than the Exercise group alone hence additional CES intervention was identified to be helpful in enhancing the cognitive function of the patients with intellectual disabilities. It is therefore estimated that the CES interventions stimulates the tiny current in the brain neurons which boost the electric and chemical activations thereby enhancing the cognitive function of the intellectually disabled.

The changes in the BDNF in the experiment showed significant increase by 52.6% in the Exercise group, and 52.3% in the Exercise + CES group. However the CES measures were found to be ineffective as there was no significant difference identified between the Exercise group and Exercise + CES group. According to the Seifert et al. [15], it has been suggested that the BDNF concentration was increased in the brain after 3 month of exercising, and the Ferris et al. [16] and Hillman et al. [17] studies have reported that the brain function was increased including cognitive function resulted by the BDNF increase through exercising. Analyzing the correlation between the cognitive function and the BDNF from this experiment, static correlation (r = 0.45, p < 0.05) was identified where increased BDNF was found to enhance the cognitive function skills. It is thereby suggested that regular exercise increase the level of the BDNF, which enhances the cognitive function of the brain. Additionally, in the experiment, the changes in the IGF-1 level in Exercise group and Exercise + CES group increased after treatment in comparison with the before treatment, yet the difference was insignificant. Eliakin [18] have suggested that there was a sudden increase in the IGF-1 level immediately after exercise, and Berg & Bang [19] study have reported that the IGF-1 concentration started to increase at 5 minutes of exercising where the peak concentration was reached at approximately 20 minutes. Considering these aspects, it is suggested that the changes in the IGF-1 level in one-off exercise reacts more vigorously in accordance with the intensity of exercise, than the level that has been stabilized before and after the treatment. On the other hand, the experiment showed significant increase in the VEGF by 63.4% in the Exercise group, and 71.4% in the Exercise + CES group. However, additional effect of CES measures could not be confirmed as there was no significant difference between the Exercise and Exercise + CES group. According to the Franzoni et al. [20], regular exercise was found to be effective in increasing the function of the endotheliocytes by increasing the productivity of the VEGF. The Bloor [21], and Prior et al. [22] studies have identified that the increased level of VEFG enhances the blood flow rate of the internal aorta and arteriole which would helps the blood supply and vascularization through peripheral reduction in the blood vessel resistance which is associated with the brain cognitive function. From the experiment, the aquatic exercise increased the VEGF level in the brain that positively affected the brain vascular cells and blood flow rate, which could explain why there had been an increased cognitive function. As follows, the aquatic exercise has been shown to be effective in improving cognitive function of the intellectually disabled patients and additional CES interventions was shown to improve even in greater effect in the cognitive function skills. Additionally, regular exercise increased the concentration of BDNF and VEGF where as BDNF and VEGF level increased, the cognitive function skill too increased.

The purpose of this study was to investigate the effects of aquatic exercise and CES treatment on the cognitive function by using K-WAB and BDNF, IGF-1, and VEGF of persons with intellectual disabilities. Cognitive function level were significantly increased in exercise + CES group than exercise group and control group. The changes of blood IGF-1 concentration were no significant difference among groups. The changes of blood BDNF and VEGF concentration were significantly increased in exercise group and exercise + CES group than control group. As a result, it can be explain that exercise helps cognitive function of persons with intellectual disabilities and micro-current stimulation with CES treatment further improves cognitive function by activating nerve cell. In addition, it can be suggested that the increment of BDNF by exercise stimulates the production of brain cells and the increase of VEGF by exercise accelerates the production of endothelial cells. In conclusion, it can be concluded that CES treatment with exercise can amend cognitive function of persons with intellectual disabilities more effectively and increase of BDNF and VEGF by exercise can explain the cognitive function improvement of persons with intellectual disabilities.