DSM Shift of Diagnosis Influence on Research Results of the Mirror Neuron Activation on the Autistic Brain.

In 2015, two years after the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was publishedA. Posar, F. Resca, P. Visconti, 2015 reported two cases of two seven years old boys who are diagnosed under the DSM-5 with ASD severity level 1. This diagnosis indicates symptoms of communication but not verbal impairment(American Psychiatric Association, 2013).In other words, the subject diagnosed able to speak in full sentences but unable to engage in conversations. Despite that both cases that A. Posar. et al. (2015) reported do meet these symptoms, it was mentioned that each case has different mental states, which require different support. One reported case has difficulty perceiving spatial relationships between objects while the second case was reported to have IQ level less than 70. With that in mind, A. Posar et al. (2015) suggested that using DSM-IV that was published in 1952 is more accurate than DSM-5 in diagnosing subjects with ASD. Based on DSM-IV, case one will be diagnosed with low Asperger disorder, while the second case with high Asperger Disorder, which will guarantee each case the distinguished support needed. This case report highlights the problem of the various diagnosis of ASD, which may have been leading the scientific research projects on the autistic brain activation of the Mirror Norene System (MNS) to inconsistent results. Researchers use of diagnosis based on DSM editions of their time to select their samples could have led them to include subjects in their research with heterogeneous symptoms.

The MNS is known to activate in the typically developed brain when the person is conducting and observing an action. However, in the case of an autistic brain, researchers have not located a specific way of activation in the MNS. While some researchers have passed the concept of whether the MNS functions differently in the autistic brain, starting to investigate the different connection that the mirror neurons make with other neurons in the brain, others are still indicating that there are no atypical MNS activations in the autistic brain. Knowing that most of the researches projects are using one of the DSM editions to diagnose their samples, it is unclear which edition is leading to the most consistent and accurate results. The main distinctions between DSM-IV and DSM-5 are that DSM-IV diagnosis autism with a focus on communication and verbal impairments as well as reparative behaviors (American Psychiatric Association, 2000). However, DSM-5, while including the symptoms mentioned in DSM-IV, it indicates that for a person to be diagnosed with any level of ASD, this person should exhibit symptoms of sensory interests or tendency to focus and demonstrate fascination to light, while not only performing reparative behaviors but also demonstrating interest in reparative actions that take place in the environment surrounding (American Psychiatric Association, 2013). In 2015 and based on the first draft of the DSM-5,Smith, I. C., Reichow, B., & Volkmar, F. R. (2015)used research projects on ASD that sampled its subjects based on DSM-IV to investigate if these samples will maintain their diagnosis under the DSM-5. It was found that only participants who were denoised with PDD-NOS maintain their diagnosis. Participants with non-PDD-NOS do not maintain their diagnosis under DSM-5 especially if their IQ score is greater than 70. Most variation of diagnosis was found to be in samples without PDD-NOS and IQ score greater than 70. However, the most important argument that Smith, I. C. et al. (2015)raised was that the diagnosis accuracy from DSM-IV to DSM-5 increased by 63%. Basing the hypothesis of this research paper on Huerta el al argument, if the DSM-5 has a higher level of accuracy, then we may be able to find pattern between research that will demonstrate a turning point in the results consistency. We will find more consistency of results in research of MNS activation of the autistic brain that bases its sampling process on DSM-5 diagnosis.

In this paper, six research projects were analyzed. Three research projects conducted before the DSM-5 was published (before 2013) while the other three after the DSM-5 was published (after 2013). All research projects used male teenagers, adults, or both teenagers and adults in their samples and compared the autistic brain activation of the MNS to typically developed brain participants (TD) when observing and performing actions. From research conducted before DSM-5 was published, Fan, Y.-T., Decety, J., Yang, C.-Y., Liu, J.-L., & Cheng, Y. (2010) demonstrated that the MNS, when compared to the typically developed brain does not activate abnormally, indicating that the distinction between the MNS activations is found when comparing participants with ASD diagnosis together, arguing that participants diagnosed with severe ASD show less MNS activation. This along with Raymaekers, R., Wiersema, J. R., & Roeyers, H. (2009) used Electroencephalography (EEG), and despite that their findings that compared ASD diagnosed and TD participants were congruent as Raymaekers, R. et al. (2009) likewise, indicated no differences in MNS activation between both groups, Raymaekers, R. et al. (2009) research projects found no correlation between ASD severity level and MNS activation, but atypical activation of the MNS in the autistic brain that was correlated with the participants IQ level, exhibiting that participants with higher IQ level tend to illustrate greater activation of the MNS. Both of these findings oppose with an additional research project conducted in the same year of 2010 based on the same diagnosis criteria of DSM-IV. Martineau, J., Andersson, F., Barthélémy, C., Cottier, J. P., & Destrieux, C. (2010) argued that the MNS activates in more areas of the autistic brain than it does in the typically developed brain. The MNS in the autistic brain was demonstrated, in Martineau, J. et al. (2010) research projects, to activate in the left and motor areas of the brain as well as the left cerebellum. The TD participants, on the other hand, showed activation on the left and motor area only.

After analyzing research projects that were conducted after the DSM-5 was published, it was shown that these researches used DSM-IV to diagnose their participants. Two of these research projects found atypical activation of the MNS in the autistic brain compared to the TD groups. However, while both research projects used the same range of age in their samples between 13 and18 years of age,  Perkins, T. J., Bittar, R. G., McGillivray, J. A., Cox, I. I., & Stokes, M. A. (2015) demonstrated that the MNS atypical activations in the autistic brain is manifested in the activation that is shown in the left hemisphere of the brain in compare to TD participants who showed activations in the right area of the brain. On the other hand, Fishman, I., Keown, C. L., Lincoln, A. J., Pineda, J. A., & Müller, R. A. (2014) illustrated that the atypical MNS activation in the autistic brain is manifested in the overconnectivity that these neurons make with other neurons in the brain. Meanwhile, both of these researches correlated this atypical activation with the imitation and emotion proccing impairments, as well as the ASD severity level, Schulte‐Rüther, M., Otte, E., Adigüzel, K., Firk, C., Herpertz‐Dahlmann, B., Koch, I., & Konrad, K. (2017), suggested that MNS activation impairment and not overactivity influences the communication and the emotional processing in ASD diagnosed participants.

As was mentioned, even after the DSM-5 was published, there are still inconsistent results. When investigating the diagnosis base of these research projects, it was found that DSM-IV was used in the sampling process. The DSM-5 demonstrates recent diagnosis criteria that were published in 2013, which exhibits a criterion shift that requires time to be taken into an application. This could be the reason behind the lack of research projects that examine samples with diagnosis based on DSM-5. For that reason, the hypothesis in this research paper was not proved neither was it disproved because no research projects found has samples with diagnosis based on the DSM-5. Therefore, it is unclear whether using the DSM-5 diagnosis will lead to accuracy and consistency in experiments measuring the MNS activation in the autistic brain. However, research projects on the MNS activation in the autistic brain that samples its subjects based on the DSM-5 are needed. As was demonstrated, even research projects that used the same age range and neuroimaging devices received incongruent results. For that reason, considering new sampling process based on new diagnosis may positively influence the results, leading to consistency.

In future research projects, taking the DSM-5 as a guide for diagnosis is not the only factor that could improve the results accuracy but also using different sexes when sampling. All research projects used in this research paper, as well as most research projects around the MNS activation and ASD, uses males only in their samples. While the DSM-IV did not include females in its diagnosis criteria, DSM-5 demonstrated diagnosis that captures females’ autistic behaviors (Young, R. L., & Rodi, M. L., 2014). This could be taking into account in future research through performing block randomization method when sampling. In other words, including females in the research projects while comparing females with autism to females with a typically developed brain. That is without comparing females’ autistic states to males’ autistic states. This is to keep in consideration the argument that females are estimated to have stronger action perception than males (Mandy, W., Chilvers, R., Chowdhury, U., Salter, G., Seigal, A., & Skuse, D.2012; Lai, M. C., Lombardo, M. V., Pasco, G., Ruigrok, A. N., Wheelwright, S. J., Sadek, S. A., …& MRC AIMS Consortium. 2011). For that reason, females may demonstrate extremely high or low MNS activations. In this case, if female participants with ASD were compared with typically developed male participants while included in the same sample with autistic male participants a heterogeneity of autistic behaviors may be encountered. In other words, taking into account the possible differences between subjects with ASD while using DSM-5 in the diagnosis may influence the interpretations of the mirror neurons activation measurements and keep researchers away from bias and generalizing arguments.

In case that future research that bases its diagnosis on DSM-5 encountered the same problem of inconsistent results, taking into account the IQ level when sampling participants may indicate more consistent results. As mentioned above, it was reported that most variation between DSM-IV and DSM-5 are shown when individuals diagnosed have IQ level greater than 70. Meaning that, usually, participants who have IQ level greater than 70 and diagnosed with ASD based on DSM-IV, do not maintain their diagnosis under the DSM-5 (Smith, I. C. et al 2015). Besides, taking Raymaekers R et al. (2009) indicated the correlation between the MNS activation and the intellectual scores that participant with ASD demonstrated, there could be a relation between the intellectual level and the ASD diagnostic criteria that could be playing a role in the results that researchers are finding when measuring the MNS activations in the autistic brain. All research projects used in this research paper have participants with IQ scores greater than 70, while at the same time found inconsistent results. This highlight the suggestion that taking the intellectual level into account when denoising participants in the process of sampling should be considered as a possible factor for the results inconsistency researchers are encountering when measuring the MNS activation in the autistic brain.

 

 

 

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