Hundreds of people are affected by Dementia. Dementia is a progressive neurodegenerative syndrome that encompasses deficits in a wide variety of areas including memory, speech and language Johns, Belleville, Goupil, Ska, Gilbert, Panisset, Boysson, Phillips, Babins, Kelner, Ingils, and Chertkow (2009). This disease increases in prevalence with age doubling approximately every five years. This ranges from two percent to three percent in people sixty-five to seventy-four years old. Dementia is a type of Alzheimer's disease. Alzheimer's disease accounts for half of the people who have Dementia. The study that was conducted in this paper examined executive functioning in two forms of Dementia. Those two forms are Frontotemporal Dementia and Lewy Body Dementia. Both of these types have underlying pathologies. Diagnosis is based on clinical symptomatology rather than underlying pathology. It is hard to distinguish between Frontotemporal and Lewy Body because executive dysfunction has been identified in both types. This study focuses on four domains, working memory, inhibitory control, generative behavior, and planning Johns et al.
Executive Functioning is a multidimensional construct that has been conceptualized as high-level control over lower level cognitive functioning and higher order cognitive capacities that subserve independent, goal-directed behavior Johns et al. Frontotemporal Dementia (FTD) is said to be the most common of three major clinical syndromes of the broader category Frontotemporal Lobar Degeneration (FTLD). Besides FTD there is also semantic dementia, and nonfluent progressive aphasia. They are all characterized by insidious onset and gradual progression. People with a more defined type of FTLD have more impairment in memory when it comes to their daily activities. They also have inattention, and are not able to focus on one task. The average age of people diagnosed with FTLD is ten years earlier than people who are diagnosed with Alzheimer's disease. The mean age of people with FTD is around sixty-two years old. This age represents twelve percent of all dementias that occur before the age of sixty-five. Unlike Alzheimer's the risk of getting FTD does not increase with age Johns et al. FTD results in social and interpersonal conduct. It also is more marked attentional and executive impairment. It affects the prefrontal and anterior temporal cortices. Executive dysfunction is more likely to be seen in the subtype of FTD. This is because of how prominent frontal lobe pathology is in FTLD. There have been reports of a number of deficits in executive functioning in FTD. One of the deficits found in FTD is working memory. Inhibitory control has been found to be impaired in people with FTD as well.
Another type of dementia is Lewy Body Dementia (LBD). This type of dementia is characterized by parkinsonian motor disturbances, hallucination, and disturbances in arousal and sleep Johns et al. LBD has similar extrapyramidal features that are also in FTD. LBD's most common symptoms are executive functioning, attention, and anterograde amnesia similar to that seen in Alzheimer's disease (AD). LBD's major neuropathological feature is Lewy Body inclusions. Lewy Body inclusions are abnormal protein aggregates present in the neurons of the limbic system and neocortical regions Johns et al. The area of the brain that is affected in LBD are the anterior frontal and temporal cortices, cingulate area, insula, substantia nigra, nucleus basalis of meynert, locus ceruleus, nucleus raphe dorsalis and amygdala. The fact that the lewy body pathology occurs in the frontal lobes and disruption of ciraits, linking the frontal cortex with subcortical structures make it likely for executive dysfunction to be present in LBD Johns et al. The researchers predicted that FTD patients have better executive functioning skills than LBD patients Johns et al.
Johns et al did a study that compared FTD and LBD patients in the area of executive functioning. The researchers did analysis to see whether there were statistical differences within the two groups. Participants were collected from the Consortium on Cognition and Aging (COA). Seventeen of the participants were FTD patients. Fifteen of the participants were LBC patients. Informed consent was obtained from all participants and their families. They were examined by participating physicians to see if they qualified for the study. During the first exam patients completed a mental status assessment and a physical evaluation to confirm the diagnosis of FTD and LBD. FTD was diagnosed according to the consensus criteria by Neary and Colleagues. That is based on a change or impairment in character or social conduct. LBD was diagnosed according to the consensus criteria by McKeith and Colleagues. This study required two of the three following features: fluctuating cognition with variation in attention and alertness, recurrent visual hallucinations. Diagnosis was based on clinical judgment. Twenty elderly controls were recruited to serve as a control group. To qualify participants had to be free of serious health problems. When they first compared FTD patients and LBD patients they included the control group. All three groups were compared on important demographic variables. FTD patients were significantly younger than LBD patients. Neither the FTD nor LBD patients were younger than the control group. Since age was not significantly correlated with the study they did not use them in the comparisons with the other variables. The three groups did not differ in the years of the amount of education they completed. The control group did however have more men then the FTD and LBD patients. The patients were measured on a number of different clinical measures. There were no significant differences when they were compared on cognitive impairments. They were also measured on their subjective memory impairment. They did not find any significant levels on this measure either. The researches however did find that LBD patients showed greater impairment in basic activities of daily living. There was not a difference in Functional Activities. This was because both FTD and LBD patients were both impaired on this measure. Both groups had mild depression as well. FTD and LBD patients were tested at the clinics that were being used for the study. The control group was tested at Concordia University.
The FTD and LBD patients were given six tests that were based on executive functioning. These tests were on learning and memory, language, visuospatial function, attention, and motor praxis. The measures that were used to test executive function were Adapted Brown-Peterson Task (BPT), Letter-Number Sequencing (LNS), Hayling Test, Stroop Test, Phonemic and Semantic Fluency, and The Tower of London (TOL) Johns et al. The BPT measured whether or not the patients could remember three consonants that were presented to them. LNS test measured whether or not the patients could remember a sequence of intermixed digits and letters. The Hayling test measured if the patients have inhibitory control. They were given two separate sections. Each section contained fifteen sentences with the last word missing. The Stroop test has three different parts. Each part had a stimulus in blue, red, green, and yellow ink. They were presented to the patients in six rows, four times. The Phonemic and Semantic or Verbal fluency measured the patients in phonemic and semantic fluency tasks. The Tower of London measured whether or not the patient could match their board to the model board.
Johns et al found through this study that when FTD and LBD patients were compared to the control group (NECs) on executive functioning they scored significantly lower. When the patients were measured with the LNS the researchers found no difference between the patients when it came to their performance. The Stroop test showed that there was a difference between the FTD and LBD patients. LBD patients made more errors than FTD patients. Johns et al did not find a difference when it came to inhibition between the two groups. There was also no difference in the two groups when they were measured with the Hayling test. When the researchers measured the two groups on phonemic and semantic fluency they also found that there was no difference. When the patients were measured on planning using the TOL both groups had difficulty. Since both groups had difficulty completing the measure the test was dropped from the study. Both FTD and LBD patients showed that they were impaired on all task of executive functioning.
The study that Johns et al conducted was the first to compare FTD and LBD patients on measures that were related to executive functioning. The study found that FTD and LBD patients performed the same on the different measures they were presented with. Johns et al found that if a group did perform poorly or there was difference in the groups it was the LBD patients that underperformed. Overall when FTD and LBD patients were tested on their executive functioning skills they scored the same. This showed there is very little difference between the two different types of Dementia. In the end the research does not support the hypothesis because it shows that both groups have the same amount of executive functioning skills. I found the research to be very interesting. My family has a history of Alzheimer's disease, so it was interesting to read about to different subtypes of this disease. It was also interesting to see what impairments what this disease causes people to have. I wish that the authors had compared the two different subtypes in other areas as well not just executive functioning. This because then the reader could know all the things that the disease entails and not just the part about executive functioning.