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Difference between revisions of "5° Clinical case: Spontaneous Electromyographic Activity"
5° Clinical case: Spontaneous Electromyographic Activity (view source)
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== Abstract == | == Abstract == | ||
[[File:EMG Propofol.jpeg|left|300x300px]] | [[File:EMG Propofol.jpeg|left|300x300px]] | ||
The chapter explores the diagnostic utility of electromyography in Orofacial Pain (OP) and Temporomandibular Disorders (TMDs), questioning | The chapter explores the diagnostic utility of electromyography in Orofacial Pain (OP) and Temporomandibular Disorders (TMDs), questioning conventional understandings of muscle rest and activity. It reviews literature indicating that myofascial trigger points and associated pain can significantly alter electromyographic patterns in masticatory muscles, complicating the diagnosis and treatment of TMDs. | ||
Studies, including those by Zieliński et al., show that electromyographic changes in masticatory muscles are often linked with myofascial pain and depression, influencing the resting bioelectrical activity of these muscles. These findings suggest that psychological factors, like depression, could exacerbate or influence the manifestation of TMD symptoms, warranting a holistic diagnostic approach that includes psychological assessment. | |||
Studies by Zieliński et al. | |||
A 65-year-old female, previously diagnosed with TMDs, exhibited orofacial pain and electromyographic abnormalities not typical of TMDs. Advanced electromyographic analysis revealed patterns inconsistent with typical TMD diagnosis, suggesting an underlying neurological condition rather than a primary muscular disorder. This case emphasizes the need for comprehensive diagnostic approaches that go beyond standard TMD protocols. | A 65-year-old female, previously diagnosed with TMDs, exhibited orofacial pain and electromyographic abnormalities not typical of TMDs. Advanced electromyographic analysis revealed patterns inconsistent with typical TMD diagnosis, suggesting an underlying neurological condition rather than a primary muscular disorder. This case emphasizes the need for comprehensive diagnostic approaches that go beyond standard TMD protocols. | ||
The chapter | The chapter discusses the use of electromyography in diagnosing TMDs, highlighting the need to distinguish between different types of muscle activities and their implications for TMD. It covers various electromyographic phenomena such as insertion activity, spontaneous activity, motor unit potentials, and recruitment patterns, which help differentiate between normal and pathological conditions. | ||
In-depth analysis using needle EMG helps | In-depth analysis using needle EMG helps understand the complex interplay between muscle activity and TMD symptoms. The chapter describes the technical aspects and findings from needle EMG, including the analysis of motor unit action potentials and their relevance in confirming or refuting a TMD diagnosis. | ||
An experimental study involving pharmacological intervention | An experimental study involving pharmacological intervention used Propofol to discern the effects of central nervous system depressants on muscle activity. This study aimed to differentiate between central and peripheral contributions to muscle activity in TMDs, providing insights into the central modulation of orofacial pain. | ||
The chapter concludes that TMDs are | The chapter concludes that TMDs are multifactorial conditions where muscle activity can be influenced by central nervous system factors, psychological conditions, and local muscle pathology. It calls for a multidisciplinary approach to diagnose and treat TMDs effectively, incorporating advanced diagnostic techniques like electromyography and considering psychological assessments as part of the routine evaluation. | ||
The findings suggest that future research should | The findings suggest that future research should integrate neuropsychological and electromyographic assessments to better understand the etiology of TMDs. This approach could lead to more effective and targeted treatments, improving outcomes for patients suffering from this complex disorder. | ||
{{ArtBy|autore=Gianni Frisardi}} | |||
===Introduction === | ===Introduction === | ||
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=====Propofol===== | =====Propofol===== | ||
The effects of anesthetics produce loss of consciousness, memory, changes in spontaneous activity, attenuation of protective reflexes, loss of postural reflexes and also adverse effects such as hallucinations, euphoria and amnesia. Furthermore they may affect the level or homeostasis of neurotransmitters in the brain such as dopamine, noraepinephrine and acetylcholine (ACh).<ref>Angel A. : Central neuronal pathways and the process of anaesthesia. British Journal of Anaesthesia 1993; 71:148-163</ref> Ach was the first neurotransmitter to be described and cholinergic neurons are widely distributed in the brain. Cholinergic mechanisms are known to be important in the striatum where a balance between dopamine and ACh release ensures normal motor output,<ref>Iversen SD.: Behavioural evaluation of cholinergic drug. Life Sciences 1997; 60: 1145-1152</ref> hippocampus and frontal cortex where ACh plays an important role in the regulation of consciousness, memory etc. | The effects of anesthetics produce loss of consciousness, memory, changes in spontaneous activity, attenuation of protective reflexes, loss of postural reflexes and also adverse effects such as hallucinations, euphoria and amnesia. Furthermore they may affect the level or homeostasis of neurotransmitters in the brain such as dopamine, noraepinephrine and acetylcholine (ACh).<ref>Angel A. : [https://www.bjanaesthesia.org/article/S0007-0912(17)45772-2/pdf Central neuronal pathways and the process of anaesthesia.] British Journal of Anaesthesia 1993; 71:148-163</ref> Ach was the first neurotransmitter to be described and cholinergic neurons are widely distributed in the brain. Cholinergic mechanisms are known to be important in the striatum where a balance between dopamine and ACh release ensures normal motor output,<ref>Iversen SD.: Behavioural evaluation of cholinergic drug. Life Sciences 1997; 60: 1145-1152</ref> hippocampus and frontal cortex where ACh plays an important role in the regulation of consciousness, memory etc. | ||
Propofol is thought to potentiate the inhibitory effect of GABAA receptors and to have a different action from barbiturates or benzodiazepines. An elegant study<ref>Kikuchi T, Wang Y, Sato K, Okumura F.: In vivo effects of propofol on aceylcholine release from the fronatl cortex, hippocampus and striatum studied by intracerebral microdialysis in freely moving rats</ref> carried out through intracerebral microdialysis in mice demonstrated that propofol, with doses of 50 mg/kg, decreased the release of ACh from the frontal cortex by 85%, by 72% by the hippocampus and by 19% by the striatum. | Propofol is thought to potentiate the inhibitory effect of GABAA receptors and to have a different action from barbiturates or benzodiazepines. An elegant study<ref>Kikuchi T, Wang Y, Sato K, Okumura F.: [https://www.bjanaesthesia.org/article/S0007-0912(17)40431-4/pdf In vivo effects of propofol on aceylcholine release from the fronatl cortex, hippocampus and striatum studied by intracerebral microdialysis in freely moving rats]Br J Anaesth. 1998 May;80(5):644-8. doi: 10.1093/bja/80.5.644.</ref> carried out through intracerebral microdialysis in mice demonstrated that propofol, with doses of 50 mg/kg, decreased the release of ACh from the frontal cortex by 85%, by 72% by the hippocampus and by 19% by the striatum. | ||
=====Blink reflex===== | =====Blink reflex===== | ||
The blink is a reflex that is evoked by hitting the eyebrow region on one side of the forehead. Electrophysiologically it is possible to evoke it by applying an electrical stimulus on the eyebrow arch in correspondence with the supraorbital foramen. The responses are recorded through two surface electrodes positioned on the orbicularis oculi muscle on each side and the motor potentials can be mainly represented by two events, namely the ipsilateral R1 response to stimulation and the bilateral R2. These responses represent a monosynaptic and polysynaptic circuitry for R1 and R2 respectively. The R1 response was considered to follow a trigeminal pathway in the pons while the R2 via a pathway adjacent the reticular formation reaches the facial nuclei.<ref>Ongerboer de Visser BW, Kuypers HG (1978): Late blink reflex changes in lateral medullary lesions. An electrophysiological and neuro-anatomical study of Wallenberg's syndrome. ''Brain'' '''101''': 285-294. </ref><ref>Ongerboer de Visser BW (1983b): Comparative study of corneal and blink reflex latencies in patients with segmental or with cerebral lesions. In: Desmedt JE , editor. ''Advances in neurology''. New York: Raven Press. p 757-772.</ref><ref>Ongerboer de Visser BW (1983b): Comparative study of corneal and blink reflex latencies in patients with segmental or with cerebral lesions. In: Desmedt JE , editor. ''Advances in neurology''. New York: Raven Press. p 757-772.</ref> | The blink is a reflex that is evoked by hitting the eyebrow region on one side of the forehead. Electrophysiologically it is possible to evoke it by applying an electrical stimulus on the eyebrow arch in correspondence with the supraorbital foramen. The responses are recorded through two surface electrodes positioned on the orbicularis oculi muscle on each side and the motor potentials can be mainly represented by two events, namely the ipsilateral R1 response to stimulation and the bilateral R2. These responses represent a monosynaptic and polysynaptic circuitry for R1 and R2 respectively. The R1 response was considered to follow a trigeminal pathway in the pons while the R2 via a pathway adjacent the reticular formation reaches the facial nuclei.<ref>Ongerboer de Visser BW, Kuypers HG (1978): Late blink reflex changes in lateral medullary lesions. An electrophysiological and neuro-anatomical study of Wallenberg's syndrome. ''Brain'' '''101''': 285-294. </ref><ref>Ongerboer de Visser BW (1983b): Comparative study of corneal and blink reflex latencies in patients with segmental or with cerebral lesions. In: Desmedt JE , editor. ''Advances in neurology''. New York: Raven Press. p 757-772.</ref><ref>Ongerboer de Visser BW (1983b): Comparative study of corneal and blink reflex latencies in patients with segmental or with cerebral lesions. In: Desmedt JE , editor. ''Advances in neurology''. New York: Raven Press. p 757-772.</ref> | ||
The main neural circuitry of the blink reflex is located in the brainstem but recent work, using functional magnetic resonance imaging (fMRI), has demonstrated that two main areas in the posterior lobe of the cerebellar hemisphere, mainly on the side ipsilateral to the stimulation, are activated during the blink reflexes in humans.<ref>Dimitrova A, Weber J, Maschke M, Elles HG, Kolb FP, Forsting M, Diener HC, Timmann D. Eyeblink-related areas in human cerebellum as shown by fMRI. Hum Brain Mapp. 2002 Oct;17(2):100-15.</ref> | The main neural circuitry of the blink reflex is located in the brainstem but recent work, using functional magnetic resonance imaging (fMRI), has demonstrated that two main areas in the posterior lobe of the cerebellar hemisphere, mainly on the side ipsilateral to the stimulation, are activated during the blink reflexes in humans.<ref>Dimitrova A, Weber J, Maschke M, Elles HG, Kolb FP, Forsting M, Diener HC, Timmann D. [https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/12353244/ Eyeblink-related areas in human cerebellum as shown by fMRI.] Hum Brain Mapp. 2002 Oct;17(2):100-15.</ref> | ||
====Experimental procedure==== | ====Experimental procedure==== | ||
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An adequate answer to this question was given by a study by Adour KK<ref>Adour KK. Acute temporomandibular joint pain-dysfunction syndrome: neuro-otologic and electromyographic study. Am J Otolaryngol. 1981 May;2(2):114-22. doi: 10.1016/s0196-0709(81)80028-2.PMID: 7270801</ref> through a prospective study using neuro-otological examination and electromyography. Seven consecutive patients with cardinal symptoms of temporomandibular joint pain syndrome (pain, tenderness, clicking, and limitation of jaw movement) were evaluated within one week of the onset of their acute symptoms. Three others with chronic symptoms were tested for comparison with acute cases. All seven patients with the acute condition had asymptomatic hypoesthesia of all three divisions of the trigeminal nerve and decreased action potential of the volitional muscles in the masseter and temporal muscles. At the end of three weeks the hypesthesia resolved in all seven patients and the muscle action potential returned to normal in six of the seven. EMG testing of the single patient with persistent reduced muscle action potentials and three patients with chronic symptoms showed fibrillation, reduced polyphasic regeneration potentials, and spontaneous fasciculations with clinical atrophy and spasm of the affected masseter and temporal muscles. Other acute cranial nerve findings included unilateral glossopharyngeal and second cervical nerve hypoesthesia, motor paralysis of the superior laryngeal branch of the vagus nerve, and increased facial nerve latency. These findings suggest a neuromuscular, rather than a psychophysiological, organic cause of temporomandibular joint pain syndrome. | An adequate answer to this question was given by a study by Adour KK<ref>Adour KK. Acute temporomandibular joint pain-dysfunction syndrome: neuro-otologic and electromyographic study. Am J Otolaryngol. 1981 May;2(2):114-22. doi: 10.1016/s0196-0709(81)80028-2.PMID: 7270801</ref> through a prospective study using neuro-otological examination and electromyography. Seven consecutive patients with cardinal symptoms of temporomandibular joint pain syndrome (pain, tenderness, clicking, and limitation of jaw movement) were evaluated within one week of the onset of their acute symptoms. Three others with chronic symptoms were tested for comparison with acute cases. All seven patients with the acute condition had asymptomatic hypoesthesia of all three divisions of the trigeminal nerve and decreased action potential of the volitional muscles in the masseter and temporal muscles. At the end of three weeks the hypesthesia resolved in all seven patients and the muscle action potential returned to normal in six of the seven. EMG testing of the single patient with persistent reduced muscle action potentials and three patients with chronic symptoms showed fibrillation, reduced polyphasic regeneration potentials, and spontaneous fasciculations with clinical atrophy and spasm of the affected masseter and temporal muscles. Other acute cranial nerve findings included unilateral glossopharyngeal and second cervical nerve hypoesthesia, motor paralysis of the superior laryngeal branch of the vagus nerve, and increased facial nerve latency. These findings suggest a neuromuscular, rather than a psychophysiological, organic cause of temporomandibular joint pain syndrome. | ||
Contrary to this assertion that sees an organic neuromotor disturbance at the basis of a clinical situation of TMDs, there is the opinion that the influence of the unilateral posterior crossbite on the variations of spontaneous muscle activity in the mandibular rest position and in maximum voluntary contraction is significant and confirmed by Woźniak K et al.<ref name=":0">Woźniak K, Szyszka-Sommerfeld L, Lichota D. The electrical activity of the temporal and masseter muscles in patients with TMD and unilateral posterior crossbite. Biomed Res Int. 2015;2015:259372. doi: 10.1155/2015/259372. Epub 2015 Mar 26.PMID: 25883948 </ref> | Contrary to this assertion that sees an organic neuromotor disturbance at the basis of a clinical situation of TMDs, there is the opinion that the influence of the unilateral posterior crossbite on the variations of spontaneous muscle activity in the mandibular rest position and in maximum voluntary contraction is significant and confirmed by Woźniak K et al.<ref name=":0">Woźniak K, Szyszka-Sommerfeld L, Lichota D. [https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/25883948/ The electrical activity of the temporal and masseter muscles in patients with TMD and unilateral posterior crossbite]. Biomed Res Int. 2015;2015:259372. doi: 10.1155/2015/259372. Epub 2015 Mar 26.PMID: 25883948 </ref> | ||
Having already clarified, albeit not in depth, the terminological, clinical and scientific difficulty in understanding phenomena that represent an alteration of the trigeminal Central Nervous System in EMG activity at rest, we can only suggest more attention in planning experiments of this type. For example Woźniak K et al.<ref name=":0" /> reaches these conclusions by analyzing the asymmetry between sides of the EMG activity at rest and at maximum will to contract (MVC) and the algorithm used is the following:<math>As=\frac{\textstyle \sum_{i=1}^N |R_i-L_i|\displaystyle}{\textstyle \sum_{i=1}^N |R_i+L_i|\displaystyle} | Having already clarified, albeit not in depth, the terminological, clinical and scientific difficulty in understanding phenomena that represent an alteration of the trigeminal Central Nervous System in EMG activity at rest, we can only suggest more attention in planning experiments of this type. For example Woźniak K et al.<ref name=":0" /> reaches these conclusions by analyzing the asymmetry between sides of the EMG activity at rest and at maximum will to contract (MVC) and the algorithm used is the following:<math>As=\frac{\textstyle \sum_{i=1}^N |R_i-L_i|\displaystyle}{\textstyle \sum_{i=1}^N |R_i+L_i|\displaystyle} | ||