Incidence of stroke increases sharply with age and the cognitive sequelae of stroke increases significantly along with the increasing number of elderly. Stroke is a syndrome characterized by sudden disruption of blood supplyto the brain and therapid development of focal neurologicaldeficit. Stroke is a significant cause of cognitive problems and has become the biggest risk factor for cognitive impairment. Many studies have shown the pathophysiological processes of dementia has begun prior to cognitive symptoms. Vascular cognitive impairment (VCI) occurs when cognitive dysfunction is caused by cerebrovascular disease. VCI is a syndromeaccompanying clinical stroke which involves impairment in at least one cognitive domain.

The purpose of this study is to determine whether there is any deterioration of cognitive function and quality of life during treatment for up to 6 months after onset of stroke.

The study is a cohort prospective observational study which identified the change of cognitivefunction in the first week and the followingsix months after the first ischemic stroke. Changes in cognitive function domains and quality of life were later analyzed. Cognitive function was evaluated using Mini Mental State Examination (MMSE), Executive neuropsychological tests (Trail A-B), Clock Drawing Test, Verbal Fluency Test and Hachinski Ischemic Score. Quality of life was measured by Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL).

Thirty four patients were enrolled in the study. The result showed average age was 59.74 ± 9.961 years with an average score of the first Mini Mental State Examination (MMSE) was 24.91 ± 4.634. The most risk factors were hypertension about 82.4%. On the 6-months follow-up, there was a significant decrease for the total score of MMSE andMMSE components such as orientation and recall (p<0.05). No statistically significant difference found on registration, attention, language and drawing. The executive function, examination Clock Drawing Test (CDT), Trial Making Test A (TMT-A) and Trial Making Test B (TMT-B) showed statistically significant decrease (p<0.05),in contrastwith the Verbal Fluency Test (VFT). VCIwas found in 15 (44.1%) of patients after stroke. There were statistically significant decrease in ADL and IADL (p<0.05).

Conclusion

There were significant impairment of cognitive function and quality of life during treatment and 6 months afteronset of stroke.

Keywords: Changing of Cognitive Function; Quality of Life; Post Ischemic Stroke

Introduction

Stroke is one of major cause of death and a major source of disability and mortality worldwide[1]. Stroke is an important cause of either simple or complex cognitive problems. This study will be focused on ischemic stroke. Most of noticeable risk factors for stroke are modifiable ones such as hypertension, diabetes, hyperlipidemia, cardiac disease, smoking, alcohol and physical inactivity. There were also non-modifiable risk factors such as age, sex, ethnic and family history[2]. In general, cerebrovascular lesions caused by stroke creates three distinct effects on cognitive and behavior: loss of function, a decrease of function and a disorganization of function. The most direct effect of stroke is loss of function, in which patient can no longer perform a specific cognitive or behavioral task. Many patients with ischemic stroke showed a significant impairment in all neuropsychological tests including memory (verbal and visual memory), attention, language, orientation, abstract reasoning and visuospatial abilities [2,3]. Dementia is a syndrome characterized by declining cognitive abilities. Vascular dementia is diagnosed when a syndrome of dementia or cognitive impairment is found with the evidence of stroke [4,5]. Vascular cognitive impairment (VCI) is a term that encompasses all forms of cognitive impairment related to vascular disease, including milder forms of cognitive impairment not meeting the criteria for dementia [6]. VCI is a syndrome or phenotype, but not a disease, although VCI is the second most common cause of cognitive impairment in later life [7]. VCI is a modern entity related to the effect of stroke in cognitive function prior tothe vascular burden of the brain, and includes all levels of cognitive impairment in one or more cognitive domains, and as such VCI replaces an earlier paradigm of vascular dementia [7,8].

Cognition is a process of registering sensory inputs, remembering a moment and communicating each other to create outputs.

The cognitive domains consist of attention, memory, language, perception, visuospatial and executive function. The Neuropsychological test typically shows impairment in multiple domains, including attention, frontal or executive function and speed of processing. There is no single characteristic cognitive or behavioral profile for VCI. Memory impairments are typically secondary to attention and frontal or executive dysfunction [7,9]. There are many tests available for evaluating cognitive function. Likewise, it should be kept in mind that certain neuropsychological tests may have multiple sensory, motor, perceptual and cognitive domains[3,7].

Cognitive screening tools are important to identify the presence of cognitive impairment. There are many tests available, for example, the simple bedside tests to evaluate attention such as The Symbol Digit Modalities Test which includes time and place orientation, forward and/or backward digit span(counting down from 20to 1, saying the months of the year or the days of the week backward). The Mini-Mental State Examination (MMSE) is a quantitative measurement used in monitoring changes in cognitive function. The MMSE is the most widely used cognitive screening tool due to a high degree of validity in detecting dementia and a short time examination (5-10 minutes). Examples of item for attention or concentration is performing serial sevens (subtracting 7 from 100 repeatedly) or spelling the word 'WAHYU' or 'familiar word' backward, while memory is tested by recalling three items (appletable- penny). Items for language are tested by confrontation of naming and word finding[10,11,12].

Executive neuropsychological tests sometimes overlap with sustained attention, trails A and B (from Halstead-Reitan battery) and CLOX Test. The Trails A and B test also requires a sequence and interpretation of proverbs in a popular bedside test, the result of which may suggestfrontal lobe problems. Clock drawing is one of popular test for cognitive impairment which is quick and simple but sometimes has a wide range of cognitive domains [11,12,13,14]. Activities Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) scale areused for assessing the functional status and occupational function as a consequence of cognitive declinement, such asindependency of using the telephone, capability of travelling by oneself, capability of using public transportation and responsibility of taking medications and finances by oneself[12,14].

Methods

This study was designed as cohort prospective observational study. Samples underwent cognitive function assessment on the first week and onthe follow-up done six months after the first ischemic stroke. Samples were taken from Sanglah General Hospital during a period of six months. Assessment was made by using MMSE, Executive neuropsychological tests (Trail A-B), Clock Drawing Test and Verbal Fluency Test; while the Functional follow-up was assessed with Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL).

Study Procedures
We collected consecutively 34patientswho were admitted to Sanglah Hospital and who werefollowed up at the outpatient clinic on the sixth month after the onset of stroke. The inclusion criterias were: first time stroke, age50-75 years old; and the exclusion criteria was major psychiatric disorders.

This study aimed to identify cognitive impairment by recording assessment madeon the first week and the sixth month follow-up, respectively. The assessment consisted ofthe MMSE, The Clock Drawing Test, The Trail Making Test (Parts A and B) and The Verbal Fluency Test; all of which measured higher cognitive abilities, executive function skills, including speed for visual searching and skill for visuo-constructional and verbal reasoning.

Results

Thirty four eligible stroke ischemic patients met the inclusion criteria for this

From table 1, the average age of the subjects was 59.74 ± 9.961 years. There were twenty males (58.8%) and fourteen females

(41.2%). All subjects were married. The most level of education was Senior High School (n=16; 47%) and majority of subjects were private employees (n=6; 17.6%) and self-employed (n=6; 17.6%). There were nineteen subjects (55.9%) with right-sided paralysis and fifteen (44.1%) with left-sided paralysis. The average of MMSE score at first stroke was 24.91 ± 4.634, in which ten subjects (29.4%) had cognitive impairment and 24 subjects (70.6%) had normal cognitive function.

Table 2 showed 28 subjects (82.4%) with hypertension, six subjects (17.6%) with diabetes mellitus, one subject (2.9%) with smoking, five subjects (14.7%) with dyslipidemia, six subjects (17.6%) with atrial fibrillationand two subjects (5.9%) with TIA.

Table 3 showed change in various domains of cognitive function six months after onset of stroke. Regarding to MMSE components, eighteen subjects showed deterioration, two subjects improved and four subjects remained constant on orientation function. These changes were statistically significant (p=0.02). For registration function, only one subject improved, while the rest were constant; this, however, was statistically insignificant (p=0.317). For attention function, tensubjects showed decreased function, two subjects improved, and 22 subjects remained constant; again, this was statistically insignicant (p=0.65). For language function, two subjects experienced worsening, three improved and 29 subjects were constant; this result was statistically insignificant (p=0.336). For drawing function, three subjects experienced worsening while the rest did not have any changes (p=0.083). For MMSE total score, 24 subjects showed decrease result, only three subjects improved and the rest remained constant. There was significant difference between MMSE taken at first week following stroke attack and six months after(p<0.001 ), so were the differences found in the results

of CDT, ADL and IADL.Of all 34 patients, fifteen subjects (44.1%) had cognitive function impairment compared tonineteen subjects (55.9%) with normal cognitive function.

Table 4 showed the result of the VFT. Six subjects without impairment at initial assessment remained normal on the sixth month, while six subjects with no impairment initially showed impairment on the sixth month follow-up. Twenty one subjects got impairment both at initial and sixth month follow-up post stroke, respectively. There was no significant statistical difference (p=0.125).

In Table 5, 29 subjects assessed by TMT-A having no impairment at initial examination, but after 6 months fifteen subjects remained without impairment while the remaining fourteen showed impairment. Five patients with impairment at initial assessment remained with impairment after 6 months. The result was statistically significant (p<0.001).

Table 6 showed 24 subjects assessed with TMT-B had no impairment initially. Out of this number, five remained without impairment, while nineteen got impairment. Ten subjects with impairment initially remained with impairment after six months. This difference was statistically significant (p<0.001).

Discussion

Vascular dementia is characterized by mental slowness, impairment of planning, initiative and executive function with personality changes. Vascular Cognitive Impairment (VCI) is characterized by cognitive impairment in at least one cognitive domain. Impaired cognitive function after stroke is often diagnosed late, because the clinical symptoms of paralysis get more attention than cognitive impairment. The location of lesions and detection of cognitive impairment are crucial to make early intervention[15,16]. The most common lesions lead to cognitive impairment are the left hemisphere, supratentorial lesions, anterior and posterior cerebral artery infarction, and multiple infarcts[2,16,17,18].

In this study, the sample was first onset, thrombotic ischemic stroke patient. Most of the samples had stroke with lesions in the left hemisphere, especially in the frontal and temporal lobes which are the territory for small cerebral artery instead of the large blood vessels. The weakness of this study lied on the fact that it did not

include details about the location or volume of lesion on brain CT scan. Literatures stated that the mechanism of hemispheric specialization has not yet well-understood [19].

Lateralization in impaired cognitive function and the reason of left hemisphere lateralization as a predictor of cognitive impairment was still largely unclear, although some study mentioned that serotonergic receptor-mediated effects may take part. Study also showed that the left carotid territory infarction is 2.5 times more likely to cause impaired cognitive function after stroke [17,18,20].

In this study, 34 patients were observed and completed the study. There were nineteen subjects (55.9%) with right-sided paralysis and fifteen (44.1%) with left-sided paralysis. All patients were evaluated on the first week and sixth month after the onset of stroke. The average age was 59.74 ± 9.961 years with an average score of the first Mini Mental State Examination (MMSE) was 24.91 ± 4.634, in which ten (29.4%) had impaired cognitive function and twenty four (70.6%) normal. The result resembled those reported by Framingham on a long-term observation on 74 patients with stroke and 74 with no stroke as control, in which the MMSE score of stroke patients was lower than control, with a mean MMSE score post stroke was 23.6 ± 0.9, and mean MMSE control was 28.3 ± 0.2 (p<0.001).

Statistically significant decrease was found in total scores of MMSE and MMSE components such as orientation and recall (p < 0.05) on the sixth month follow-up. There was no difference found for registration, attention, language and drawing. The executive function, CDT, TMT-A and TMT-B showed significant deterioration (p<0.05), however, the VFT result was not statistically significant. VCI occurred in fifteen (44.1%) subjects. There was significant deterioration in ADL and IADL score (p<0.05). Previous study showed that the risk of cognitive impairment after a stroke generally worse in patients with neurological deficit following a severe stroke[18,22]. Interestingly, another study reported that 20% of patients with cognitive impairment after stroke improved in the sixth month and as much as 10% improved after one year[23]. Impaired cognitive function understandably will affect the quality of life, including the ability to work, managing family life, financial issues and social activities [24].

In this study, VCI was significantly found six months following stroke onset. The impairment of cognitive function can be prevented by increasing the intensity of regular cognitive stimulation and giving it in continuous pattern, in order to improve cognitive function and the quality of life.

Conclusion and Suggestion

There is a significant impairment of cognitive function and quality of life during treatment and after observation for 6 months post stroke. In this study, significant executive function impairment was found post-stroke, which affected the ability to work after suffering from stroke. More attention and focus is needed for early detection and prevention from cognitive function impairment –a practice that has long been less prioritized–, during the early treatment of stroke, and to follow it up with continuous and intense cognitive stimulation for better quality of life.

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