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Difference between revisions of "Trigeminal Nervous System Segmentation/it"
Trigeminal Nervous System Segmentation/it (view source)
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<span lang="en" dir="ltr" class="mw-content-ltr">Considering the safety limits, the energy provided for each individual impulse in our application will follow this formula</span>: | <span lang="en" dir="ltr" class="mw-content-ltr">Considering the safety limits, the energy provided for each individual impulse in our application will follow this formula</span>: | ||
<math>E=\bigtriangleup t =R \times I^2 \times \bigtriangleup t = 2.5 mJ </math>per impuls.[[File:Potenziale Evocato della Radice Trigeminale.jpg|thumb|''' | <math>E=\bigtriangleup t =R \times I^2 \times \bigtriangleup t = 2.5 mJ </math>per impuls.[[File:Potenziale Evocato della Radice Trigeminale.jpg|thumb|'''Figura 4:''' <span lang="en" dir="ltr" class="mw-content-ltr">By increasing the stimulus delivery, more fibers are gradually recruited until saturation</span>.]] | ||
<span lang="en" dir="ltr" class="mw-content-ltr">About the simultaneous use of the two electrostimulators — from the safety point of view — the limits turn out to have been 10 times lower than those indicated in the IEC legislation</span>. | <span lang="en" dir="ltr" class="mw-content-ltr">About the simultaneous use of the two electrostimulators — from the safety point of view — the limits turn out to have been 10 times lower than those indicated in the IEC legislation</span>. | ||
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<span lang="en" dir="ltr" class="mw-content-ltr">Hence, the first procedure is to check the saturation of the motor response of the trigeminal root</span>. | <span lang="en" dir="ltr" class="mw-content-ltr">Hence, the first procedure is to check the saturation of the motor response of the trigeminal root</span>. | ||
*<span lang="en" dir="ltr" class="mw-content-ltr">At 20 mA, 30 mA, and 40 mA, we can observe a latency of 2.4 ms, 2.4 ms, and 2.3 ms respectively, but on increasing the amperage, we can observe a decrease in latency up to 2.1 ms at 50 mA, 2 ms at 70 mA, and 1.9 ms at 80 mA, 90 mA, and 100 mA</span> ( | *<span lang="en" dir="ltr" class="mw-content-ltr">At 20 mA, 30 mA, and 40 mA, we can observe a latency of 2.4 ms, 2.4 ms, and 2.3 ms respectively, but on increasing the amperage, we can observe a decrease in latency up to 2.1 ms at 50 mA, 2 ms at 70 mA, and 1.9 ms at 80 mA, 90 mA, and 100 mA</span> (Figura 3). | ||
*<span lang="en" dir="ltr" class="mw-content-ltr">These latency differences reach up to a maximum current density, depending on the capacitive components and resistance of the tissues to the current flow</span>. | *<span lang="en" dir="ltr" class="mw-content-ltr">These latency differences reach up to a maximum current density, depending on the capacitive components and resistance of the tissues to the current flow</span>. | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The saturation of the electrophysiological signal evoked by the trigeminal root is the first absolute and mandatory step that needs to be performed, even before clinical interpretation</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The saturation of the evoked potentials from the trigeminal root showed no change in amplitude</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Matter of fact, when the electrostimulator reaches 80 mA pulses, 90 mA, and 100 mA, the P-P amplitude stabilizes at 4.6 mV</span> ( | <span lang="en" dir="ltr" class="mw-content-ltr">The saturation of the electrophysiological signal evoked by the trigeminal root is the first absolute and mandatory step that needs to be performed, even before clinical interpretation</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The saturation of the evoked potentials from the trigeminal root showed no change in amplitude</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Matter of fact, when the electrostimulator reaches 80 mA pulses, 90 mA, and 100 mA, the P-P amplitude stabilizes at 4.6 mV</span> (Figura 4). <span lang="en" dir="ltr" class="mw-content-ltr">The amplitude value of 4.6 mV (of course, the amplitude can be chosen to the integral area or vice versa, depending on the purpose of the study) is to be considered the ‘''Maximum Absolute value of Neural Evoked Energy''’ from the trigeminal motor system</span>. <span lang="en" dir="ltr" class="mw-content-ltr">It is called</span> '''‘<sub>m</sub>ANEE’'''. | ||
[[File:Test trigeminali.jpg|left|thumb|''' | [[File:Test trigeminali.jpg|left|thumb|'''Figura 5:''' <span lang="en" dir="ltr" class="mw-content-ltr">Tests mainly used in trigeminal neurophysiopathology</span>]] | ||
===<span lang="en" dir="ltr" class="mw-content-ltr">Trigeminal Brainstem Area</span>=== | ===<span lang="en" dir="ltr" class="mw-content-ltr">Trigeminal Brainstem Area</span>=== | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The trigeminal brainstem area is the most complex area to study and interpret because of the complexity of its multi-synaptic connections</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The following electro-physiological tests are objectively sufficient to understand the cryptic language of the SCNS</span>. <span lang="en" dir="ltr" class="mw-content-ltr">These will be treated in this section, but they will also be resumed in other editions</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The following trigeminal reflexes will be considered</span>: <span lang="en" dir="ltr" class="mw-content-ltr">the ''jaw jerk'', the ''mechanical and electrical silent period'', the ''recovery cycle of the masseteric inhibitory reflex'' and the ''laser silent period'', as well as the ''masseteric laser-evoked potentials''</span> ( | <span lang="en" dir="ltr" class="mw-content-ltr">The trigeminal brainstem area is the most complex area to study and interpret because of the complexity of its multi-synaptic connections</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The following electro-physiological tests are objectively sufficient to understand the cryptic language of the SCNS</span>. <span lang="en" dir="ltr" class="mw-content-ltr">These will be treated in this section, but they will also be resumed in other editions</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The following trigeminal reflexes will be considered</span>: <span lang="en" dir="ltr" class="mw-content-ltr">the ''jaw jerk'', the ''mechanical and electrical silent period'', the ''recovery cycle of the masseteric inhibitory reflex'' and the ''laser silent period'', as well as the ''masseteric laser-evoked potentials''</span> (Figura 5). | ||
====<span lang="en" dir="ltr" class="mw-content-ltr">Jaw jerk Reflex</span>==== | ====<span lang="en" dir="ltr" class="mw-content-ltr">Jaw jerk Reflex</span>==== | ||
[[File:Riflesso mandibolare.jpg|left|thumb|''' | [[File:Riflesso mandibolare.jpg|left|thumb|'''Figura 6:''' <span lang="en" dir="ltr" class="mw-content-ltr">Mandibular reflex performed with Nihon Kohden instrumentation</span>]] | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The piezoelectric trigger is used for the mandibular reflex, though it does not provide controlled reproducibility and quantification of the stimulation intensity</span>; <span lang="en" dir="ltr" class="mw-content-ltr">simultaneous recordings of the two sides are considered an essential method for the accurate and acceptable assessment of the asymmetry of the side</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Asymmetry in the latency is very small: it ranges from 0 to 0.8 ms with an average of 0.13 ms (SD 0.17) in 131 normal subjects</span><ref>{{cita libro | <span lang="en" dir="ltr" class="mw-content-ltr">The piezoelectric trigger is used for the mandibular reflex, though it does not provide controlled reproducibility and quantification of the stimulation intensity</span>; <span lang="en" dir="ltr" class="mw-content-ltr">simultaneous recordings of the two sides are considered an essential method for the accurate and acceptable assessment of the asymmetry of the side</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Asymmetry in the latency is very small: it ranges from 0 to 0.8 ms with an average of 0.13 ms (SD 0.17) in 131 normal subjects</span><ref>{{cita libro | ||
| autore = Kimura J | | autore = Kimura J | ||
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| DOI = 10.1016/0013-4694(94)90131-7 | | DOI = 10.1016/0013-4694(94)90131-7 | ||
| OCLC = | | OCLC = | ||
}}</ref>. <span lang="en" dir="ltr" class="mw-content-ltr">Although in trigeminal neuropathy or multiple sclerosis the jaw jerk reflex may be retarded by several milliseconds, asymmetries of latency of only 0.8 ms were considered to be a higher limit of normality in neurological studies</span> ( | }}</ref>. <span lang="en" dir="ltr" class="mw-content-ltr">Although in trigeminal neuropathy or multiple sclerosis the jaw jerk reflex may be retarded by several milliseconds, asymmetries of latency of only 0.8 ms were considered to be a higher limit of normality in neurological studies</span> (Figura 6). | ||
<span lang="en" dir="ltr" class="mw-content-ltr">In previous studies about the jaw jerk in patients with cranial-mandibular disorders (TMDs), patients with ''unilateral'' disorders were selected to identify an affection side in which there was a latency delay and a lower amplitude on the side of the mandibular deviation and pain</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Even if the maximum mandibular closure force in TMDs can be reduced to half as much as control groups, several researchers propose that muscular hyperactivity is one of the key mechanisms in cranial-mandibular dysfunction, and that hyperactivity of the masticatory muscles is central to the nervous system</span><ref>{{cita libro | <span lang="en" dir="ltr" class="mw-content-ltr">In previous studies about the jaw jerk in patients with cranial-mandibular disorders (TMDs), patients with ''unilateral'' disorders were selected to identify an affection side in which there was a latency delay and a lower amplitude on the side of the mandibular deviation and pain</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Even if the maximum mandibular closure force in TMDs can be reduced to half as much as control groups, several researchers propose that muscular hyperactivity is one of the key mechanisms in cranial-mandibular dysfunction, and that hyperactivity of the masticatory muscles is central to the nervous system</span><ref>{{cita libro | ||
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}}</ref>. | }}</ref>. | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The afferents from group II in the division of the maxillary and mandibular trigeminal nerve apply a powerful inhibition of the motoneurons of the mastication muscles through synaptic and polysynaptic reflexes</span>. <span lang="en" dir="ltr" class="mw-content-ltr">A remarkable feature of the mandibular reflexes, however, is their bilateral symmetry</span>. <span lang="en" dir="ltr" class="mw-content-ltr">In some patients with multiple sclerosis (MS) the latency is prolonged, whereas it lacks in others: this reflex can sometimes be essential for diagnosing the lesions of the brainstem in MS</span>. <span lang="en" dir="ltr" class="mw-content-ltr">It might also be more effective for therapy</span> ( | <span lang="en" dir="ltr" class="mw-content-ltr">The afferents from group II in the division of the maxillary and mandibular trigeminal nerve apply a powerful inhibition of the motoneurons of the mastication muscles through synaptic and polysynaptic reflexes</span>. <span lang="en" dir="ltr" class="mw-content-ltr">A remarkable feature of the mandibular reflexes, however, is their bilateral symmetry</span>. <span lang="en" dir="ltr" class="mw-content-ltr">In some patients with multiple sclerosis (MS) the latency is prolonged, whereas it lacks in others: this reflex can sometimes be essential for diagnosing the lesions of the brainstem in MS</span>. <span lang="en" dir="ltr" class="mw-content-ltr">It might also be more effective for therapy</span> (Figura 6). | ||
====<span lang="en" dir="ltr" class="mw-content-ltr">Masseteric Mechanical Silent Period</span>==== | ====<span lang="en" dir="ltr" class="mw-content-ltr">Masseteric Mechanical Silent Period</span>==== | ||
[[File:PSM_-_Masseter_mechanical_Silent_Period.jpg|left|thumb|''' | [[File:PSM_-_Masseter_mechanical_Silent_Period.jpg|left|thumb|'''Figura 7:''' <span lang="en" dir="ltr" class="mw-content-ltr">Representation of a typical masseteric inhibitory reflex</span> (MSP) ]] | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The jaw jerk is a short-latency excitatory reflection that can be evoked by a stretch of the mandibular elevators through a percussion produced by a triggered neurological hammer</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The excitation on motoneurons <code>α</code> from the neuromuscular spindles is the only generally accepted explanation</span>. <span lang="en" dir="ltr" class="mw-content-ltr">When this type of mechanical stimulus is applied during voluntary activation EMG (i.e., by pressing the teeth), the jaw overlaps with the Interference EMG activity, and is followed by a period of absence or depression of the electromyographic activity, the so-called '''Masseteric Silent Period'''</span> (MSP)<ref>{{cita libro | <span lang="en" dir="ltr" class="mw-content-ltr">The jaw jerk is a short-latency excitatory reflection that can be evoked by a stretch of the mandibular elevators through a percussion produced by a triggered neurological hammer</span>. <span lang="en" dir="ltr" class="mw-content-ltr">The excitation on motoneurons <code>α</code> from the neuromuscular spindles is the only generally accepted explanation</span>. <span lang="en" dir="ltr" class="mw-content-ltr">When this type of mechanical stimulus is applied during voluntary activation EMG (i.e., by pressing the teeth), the jaw overlaps with the Interference EMG activity, and is followed by a period of absence or depression of the electromyographic activity, the so-called '''Masseteric Silent Period'''</span> (MSP)<ref>{{cita libro | ||
| autore = Goldberg LJ | | autore = Goldberg LJ | ||
| Line 274: | Line 274: | ||
| DOI = 10.1016/0006-8993(71)90330-1 | | DOI = 10.1016/0006-8993(71)90330-1 | ||
| OCLC = | | OCLC = | ||
}}</ref> ( | }}</ref> (Figura 7). | ||
<span lang="en" dir="ltr" class="mw-content-ltr">The MSP has sparked particular interest as it has been shown that the duration of the silent period is higher in patients with TMDs</span><ref>{{cita libro | <span lang="en" dir="ltr" class="mw-content-ltr">The MSP has sparked particular interest as it has been shown that the duration of the silent period is higher in patients with TMDs</span><ref>{{cita libro | ||
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====<span lang="en" dir="ltr" class="mw-content-ltr">Recovery Cycle of Masseteric Inhibitory Reflex</span>==== | ====<span lang="en" dir="ltr" class="mw-content-ltr">Recovery Cycle of Masseteric Inhibitory Reflex</span>==== | ||
[[File:CR_MIR_masseter_inhibitory_recovery_cycle_reflex.jpg|left|thumb|''' | [[File:CR_MIR_masseter_inhibitory_recovery_cycle_reflex.jpg|left|thumb|'''Figura 8:''' <span lang="en" dir="ltr" class="mw-content-ltr">Representation of the masseteric inhibitory reflex recovery cycle</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Note the pair of electrical stimuli (S1 and S2) and the corresponding silent periods</span> (ES1 e ES2)]] | ||
<span lang="en" dir="ltr" class="mw-content-ltr">Headache is oftes associated with a ‘sensitization’ of the nociceptive trigeminal system with the involvement of anti-nocicective mesenchephalic structures such as periaqueductal substance, locus coeruleus, and the nuclei of the raphe, which have a modulator effect on trigeminal sensitive nuclei</span><ref>{{cita libro | <span lang="en" dir="ltr" class="mw-content-ltr">Headache is oftes associated with a ‘sensitization’ of the nociceptive trigeminal system with the involvement of anti-nocicective mesenchephalic structures such as periaqueductal substance, locus coeruleus, and the nuclei of the raphe, which have a modulator effect on trigeminal sensitive nuclei</span><ref>{{cita libro | ||
| autore = Holle D | | autore = Holle D | ||
| Line 466: | Line 466: | ||
}}</ref>. | }}</ref>. | ||
''' | '''Bruxismo''' <span lang="en" dir="ltr" class="mw-content-ltr">is usually believed to be related to musculoskeletal pain, such as pain from TMDs, but also to muscular-tensive headache</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Few studies have actually tried to fully describe the pain associated with bruxism examining the neurobiological and physiological characteristics of the mandibular muscles</span>. <span lang="en" dir="ltr" class="mw-content-ltr">There are some clinical cases in the literature and small studies suggesting that some drugs related to dopaminergic, serotonergic, and adrenergic systems, can both suppress and exacerbate bruxism</span>. <span lang="en" dir="ltr" class="mw-content-ltr">Most of the pharmacological studies mentioned before indicate that several classes of medications can affect muscle activity related to bruxism without having any effect on Orofacial Pain</span> (OP: <span lang="en" dir="ltr" class="mw-content-ltr">Orofacial pain</span>)<ref>{{cita libro | ||
| autore = Winocur E | | autore = Winocur E | ||
| autore2 = Gavish A | | autore2 = Gavish A | ||