Difference between revisions of "Logica di sistema"

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  | autore = Diana Ferraro

  | autore2 = Roberta Bedin

  | autore3 = Patrizia Natali

  | autore4 = Diego Franciotta

  | autore5 = Krzysztof Smolik

  | autore6 = Mario Santangelo

  | autore7 = Paolo Immovilli

  | autore8 = Valentina Camera

  | autore9 = Francesca Vitetta

  | autore10 = Matteo Gastaldi

  | autore11 = Tommaso Trenti

  | autore12 = Stefano Meletti

  | autore13 = Patrizia Sola

  | autore = Huseyin Kayadibi

  | autore2 = Baris Yilmaz

  | autore3 = Abdullah Ozgur Yeniova

  | autore4 = Huseyin Koseoglu

  | autore5 = Zahide Simsek

  | url =  

  | opera = Eur J Gastroenterol Hepatol.

Un test, un dato di riferimento normativo o un 'Indice' sono strategie legate a modelli matematico-statistici che generano dati. Questi dati sono obbligatori per l'accuratezza della diagnosi, per la diagnosi differenziale e per le linee guida terapeutiche. Su questi dati di riferimento, ai tempi della storia scientifica dell'odontoiatria, si sono generate implementazioni e modifiche ma anche incertezze e convinzioni che sotto forma di assiomi o scuole di pensiero hanno tracciato linee guida non sempre scientificamente giustificabili, e talvolta false.  

  | autore = Maria Francesca Sfondrini

  | autore2 = Paolo Zampetti

  | autore3 = Giulia Luscher

  | autore4 = Paola Gandini

  | autore5 = José Luís Gandía-Franco

  | autore6 = Andrea Scribante

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  | opera = Acta Medica (Hradec Kralove)

  | autore = Spyridon N. Papageorgiou

  | autore2 = Theodore Eliades

  | autore3 = Christine Angst

  | autore = Nadia Lyotard

  | autore2 = Mark Hans

  | autore3 = Suchitra Nelson

  | autore4 = Manish Valiathan

  | autore = Birgit Thilander

  | autore = Günter Lang

  | autore2 = Günter Alfter

  | autore3 = Gernot Göz

  | autore4 = Günter H Lang

  | autore = Jeanett Steinnes

  | autore2 = Gunn Johnsen

  | autore3 = Heidi Kerosuo

  | autore = Karina Maria Salvatore de Freitas

  | autore2 = Guilherme Janson

  | autore3 = Marcos Roberto de Freitas

  | autore4 = Arnaldo Pinzan

  | autore5 = José Fernando Castanha Henriques

  | autore6 = Célia Regina Maio Pinzan-Vercelino

de Freitas, K.M., Janson, G., de Freitas, M.R., et al. [https://pubmed.ncbi.nlm.nih.gov/17920494/ Influence of the quality of the finished occlusion on postretention occlusal relapse]. American Journal of Orthodontics and Dentofacial Orthopedics, 132, 428.e9-14.</ref>, che non è un approccio di analisi elettrofisiologica del trigemino nel considerare la "Normocclusione", tanto meno i dettagli di un'occlusione ben bilanciata (come contatti, inclinazioni e allineamento di ciascun dente) o cambiamenti nella ritenzione solo a breve termine.<ref>Hoybjerg, A.J., Currier, G.F., Kadioglu, O. [https://pubmed.ncbi.nlm.nih.gov/23810041/ Evaluation of 3 retention protocols using the American Board of Orthodontics cast and radiograph evaluation.] American Journal of Orthodontics and Dentofacial Orthopedics, 2013, 144, 16-22.</ref>

A conoscenza degli autori al momento della pubblicazione del loro studio, solo uno studio<ref>Nett, B.C., Huang, G.J.[https://pubmed.ncbi.nlm.nih.gov/15821689/ Long-term posttreatment changes measured by the American Board of Orthodontics objective grading system]. American Journal of Orthodontics and Dentofacial Orthopedics, 2005, 127, 444-50.</ref> ha utilizzato il sistema di classificazione oggettiva dettagliata dell'American Board of Orthodontics (ABO)<ref>Casko, J.S., Vaden, J.L., Kokich, V.G., Damone, J., James, R.D., Cangialosi, T.J., Riolo, M.L., Owens, S.E. Jr and Bills, E.D. [https://pubmed.ncbi.nlm.nih.gov/9810056/ Objective grading system for dental casts and panoramic radiographs. American Board of Orthodontics.] American Journal of Orthodontics and Dentofacial Orthopedics, 1998, 114, 589–599.</ref> per modelli e radiografie che misura i dettagli di un'occlusione ben rifinita e ben bilanciata.

----{{q2|The aforementioned study is not only interesting but also stimulating, from a scientific point of view, as it states that relapses could occur even in the presence of adequate functional occlusion. |Constructive criticism, however, is inherent in the statement itself: how is an efficient masticatory function and, therefore, a 'Normocclusion' defined? }}

 

Let's look at the two cases below, in figure 1 and in figure 2: which of the two clinical cases do you think is affected by malocclusion?

File:Occlusal Centric view in open and cross bite patient.jpg|'''Figure 1:''' Patient with open bite and right posterior crossbite who according to classical orthodontic indices can only be considered in a state of 'Malocclusion'

File:Occlusion in young lady, needing attention.jpg|'''Figure 2:''' Daughter of the patient in figure 1 who exhibits similar anatomical features such as the right posterior crossbite. There is no openbite in this case.

It seems irreverent for the canons of orthodox orthodoxy not to share the diagnosis of 'malocclusion', but we leave the reader in a little suspense. We intend to resume extensively in a few chapters, after deepening the topic of 'System Logic' and  'Systems Theory'. We only anticipate that the patient in figure 1 has already been proposed in the chapter 'Introduction', so we already know our clinical scientific opinion but if he gives us so much, also.....  

{{q2|the daughter should also respond in the same way.|... be patient and you will see }}

===Medical language logic===

In the previous chapters we highlighted the extreme difficulties we met in defining an exact, detailed and timely diagnosis in the right time; and this is not only due to the 'Complexity' of the living system, but also to a questionable and vague logic of medical language. If [[classical logic]] is too selective (<code>true</code> or <code>false</code>, and therefore 'there is no third answer' - principle of the excluded third), it is also true that [[probabilistic logic language]], which trivially indicates the presence of a specific disease, breaks down in the 'significativity' parameter that acquires a certain value only in a 'specialist context'.

We have therefore frozen a much debated and approached concept in the chapter '[[Introduction]]': not determining a clear separation between specialist know-how, but superimposing interdisciplinary knowledge, instead, through a 'Fuzzy' approach (see [[fuzzy logic language]]). 

{{q2|But it is not so obvious to arrive at a more formal language in the medical field where events are complex and dynamic and, as we will see, they are not trivially deterministic. In order to better understand the 'System Logic', and at the same time introduce the concept of clinical 'Indices', it is necessary to start with the description of the 'Systems Theory' |}}

In the scientific field, systems theory, more properly general system theory (definition by Ludwig von Bertalanffy),<ref>{{Cita libro|autore = Ludwig von Bertalanffy|titolo = General System Theory: Foundations, Development, Applications|url = https://archive.org/details/generalsystemthe0000bert|anno = 1968|editore = George Braziller|città = New York|p = 295|ISBN = 978-0807604533}}</ref> is an often interdisciplinary field of study, straddling mathematics and natural sciences, which deals with the analysis of properties and the constitution of a system. It is essentially composed of the theory of dynamic systems (simple and complex) and of the theory of control: it is the basis of various disciplines such as automation, robotics and cybernetic physics, as well as the technical-scientific study of systems in general as much as in biology and medicine.

Systems theory is the interdisciplinary study of systems, that could be described as cohesive groups of interconnected and interdependent parts that can be natural or man-made. Each system is bounded by space and time, influenced by its environment, defined by its structure and expressed through its functioning. A system can be more than the sum of its parts if it expresses emerging synergies or behaviors.<ref>[https://pubmed.ncbi.nlm.nih.gov/?term=%22emergent+behaviour%22&filter=datesearch.y_10 Emergent Behaviour]</ref>

Changing one part of a system might affect other parts or the whole system. It may be possible to predict these changes in behavior patterns. Some systems support other systems, keeping the others to prevent failure. The goals of systems theory are to model the dynamics, constraints, conditions of a system and to clarify the principles (such as purpose, measure, methods, tools) that can be identified and applied to other systems at any level of nesting and in a 'wide range of fields to achieve optimized equifinality.<ref>[[wikipedia:Equifinality|Equifinality]]</ref>

Regarding the analysis of the state of the masticatory system, the EMG technique has been widely used but there are still a number of concerns regarding the reliability of the measures based on the interferential EMG. <ref>Reaz MB, Hussain MS, Mohd-Yasin F (2006) Techniques of EMG signal analysis: detection, processing, classification and applications (Correction). Biol Proced Online 8: 163.</ref>

This is why most of the studies performed so far aimed at showing a possible correlation between EMG signals with Temporomandibular Disorders (TMD), Orofacial Pain (OP) or Malocclusion (IO), but they have not yielded convincing results.<ref>Masci C, Ciarrocchi I, Spadaro A, Necozione S, Marci MC, et al. (2013) Does orthodontic treatment provide a real functional improvement? A case control study. BMC Oral Health 13: 57.</ref>

These patients, who actually suffer from neurological symptoms superimposed on dental-facial ones, may undergo unnecessary dental interventions before the correct diagnosis is made, sometimes too late.<ref>Moazzam AA, Habibian M (2012) Patients appearing to dental professionals with orofacial pain arising from intracranial tumors: a literature review. Oral Surg Oral Med Oral Pathol Oral Radiol 114: 749-755.</ref>

   

 

{{q2|When approaching the modeling of a diagnostic 'Index' it is essential to consider the 'Fundamental Unit' of the system to be studied mathematically.|... as said, the 'Observable' cannot be the occlusal element because it is hierarchically lower than the Trigeminal Nervous System.}}

  [[File:Bilateral Root-MEPs.jpg|thumb||center|500px|'''Figure 4:''' Virtual segmentation of the Trigeminal Nervous System and annotation of the motor Root level from which the trigeminal Motor Evoked Potentials (R-MEPs) are evoked |alt=]]

 

Cortical projections to the trigeminal motor neurons are generally believed to be bilateral and symmetrical and can be electrophysiologically analyzed by electrical or magnetic brain stimulation through the intact scalp.<ref>Merton PA, Morton HB (1980) Stimulation of the cerebral cortex in the intact human subject. Nature 285: 227.</ref>

 

In the ipsilateral masseter, the transcranial electrical stimulation (eTCS) is capable of evoking a large short-latency potential in relaxed and active muscles. The characteristics of ipsilateral Motor Evoked Potentials (MEPs) do not change under relaxed or active conditions. Mean onset latency is approximately 2 ms, peak latency of 3.9 ms and amplitude of 5.4 mV, and there is no latency variability in similar pacing conditions. These motor potentials, considered secondary to trigeminal motor root excitation, have been called Root-MEP (Root-MEP or simplified into R-MEPs) to differentiate them from M-waves and Cortex-MEPs.<ref>Cruccu G, Berardelli A, Inghilleri M, Manfredi M (1989) Functional organization of the trigeminal motor system in man. A neurophysiological study. Brain 112: 1333-1350.</ref>

To make the understanding of 'Systems Theory' more suitable for the context of the masticatory system, we report some trigeminal electrophysiological procedures and implement them with the mathematical models of the theory.

====Mathematical formalism in 'Systems Theory'====

The "systems theory" studies oriented systems, in which it becomes possible to classify the quantities of interest into two categories:

*quantities that vary over time independently from the others ('''inputs''')

*quantities whose evolution over time is to be studied, depending on the inputs, called '''outputs'''.

A real system can have multiple inputs and multiple outputs. In particular, we indicate with:

*<math>u(t)= (u_1(t),..., u_r(t))</math>the vector of the inputs at time <math>{t}</math>

*<math>y(t)= (y_1(t),..., u_m(t))</math>the vector of the output at time <math>{t}</math>

It is also generally defined as the state vector of the system in a generic instant <math>\tilde{t}</math> the information instantly <math>\tilde{t}</math> necessary to uniquely determine the output <math>y(t)</math> for each <math>t\geq{\displaystyle {\tilde {t}}}</math> once the entrance has been assigned <math>u(t), </math><math>t\geq{\displaystyle {\tilde {t}}}</math>.

We denote the state vector, whose components are defined as state variables, with the notation <math>x(t)= (x_1(t),..., x_n(t))</math> .

The inputs act on the state of the system and modify its characteristics at a given moment in time; these changes are recorded by the state variables. The values of the system outputs, usually the only measurable variables, in turn depend on the system state variables and the inputs.

The input, status and output quantities are functions of the time variable.

This takes values in an ordered subset <math>T \subseteq \R</math>, which can be continuous or discrete. In the following discussion we will consider a discrete subset of times:<math>T = \{t_0,..., t_s\}</math>

Therefore, given a set of times <math>T = \{t_0,..., t_s\}</math>, we can formally define a system as the pair of equations

with <math>x(t_0)=x_0

</math>, where <math>f

</math> is called generating function e <math>g

</math> is called the output transformation.

[[File:Potenziale Evocato della Radice Trigeminale.jpg|thumb|'''Figure 6:'''Ipsilateral trigeminal motor evoked potential|alt=|378px|right]]

 

[[File:FIGU01.jpg|alt=|left|thumb|'''Figura 7:''' The figure shows three ways of analyzing the system. In A the interferential EMG trace, in B the bilateral Root-MEPs and in C the jaw jerk..|200px]]

The irrefutable step forward made in diagnostics in most medical disciplines, as already mentioned, lies precisely in bioengineering, technological progress; specifically, systems theory has allowed us to verify the system state by comparing output variables generated by variables incoming payments which are basically triggers of various types.  

Figure 7 is a way of demonstrating this. Notably, like the interferential EMG test shows (Figure 7A), only a sort of interferential asymmetry typical of clinical situations of malocclusion can be observed, while through a trigger model (specifically, the bilateral transcranial electrical stimulation of the trigeminal roots) the system responds with a large amplitude asymmetry (Figure 7B) and even with an absence of the jaw jerk response (evoked with a mechanical trigger by striking the chin with a neurological piezoelectric hammer). (Figure 7C) The diagnostic conclusion of this patient was of skull base menygoma.

For the experts, of course, a glance is enough to understand whether the trigeminal motor system evoked through electrical transcranial stimulation of the motor roots is in a physiological or pathological state; but, as we will see in the next chapters, the biological reality is so complex and paradoxically indeterministic, that a bioengineering model paired with an adequate statistical mathematician will allow us to approach more accurately the real physiopathological state of the system, reduce the uncertainty of the measurement and consequently the differential diagnostic error but above all make early diagnosis.  

In any case, if this patient had undergone the described diagnostic model, he would not have died, because the growth of the tumor mass of a meningioma is extraencephalic, and slow, and would have shown an electrophysiologically documentable destructuring many years before the vertiginous symptomatology.

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