Electrophysiological evaluation of motor neuron involvement in ALS

ALS/MND (Motor Neuron Disease) is a rare, progressive and neurodegenerative disease with a poor prognosis. While electrophysiological examination of lower motor neuron involvement have already well defined, electrophysiological methods for upper motor neuron involvement are still being discussed and are not yet included in any diagnostic criteria. We think that the evaluation of these two basic supplementary nervous system structures in ALS cases can contribute to the process of disease by providing an early and more precise diagnosis. There was almost no study in the literature examining both spinal and cortical excitability in ALS as an upper motor neuron evidence, thus we started from this point.. Our aim in this thesis study is finding a solution to the question of studying the early electrophysiological spinal and cortical excitability changes of upper motor neuron involvement in patients with ALS together and with more detailed technical methods can be a powerful significant supportive electrophysiological marker that can even be included in the diagnostic criteria for upper motor neuron involvement in ALS. During this thesis study, which lasted for a total of 19 months, we included 52 patients (30 male, 22 female) with a similar age/gender distribution and a total of 20 control cases (8 males and 12 females). There was a bulbar onset in 9 (17.3%), cervical in 22 (42.3%), lumbosacral in 20 (38.5%), and respiratory onset in 1 of the cases. According to the Revised El-Escorial criteria of the cases, 25 (48.1%) were definite ALS, 14 (26.9%) probable ALS, 13 (25.0%) laboratory-supported ALS; According to the Awaji Criteria, 24 (46.2%) patients were diagnosed with definite ALS, 16 (30.8%) probable ALS, 12 (23.1%) probable ALS, and all 52 patients (100%) according to Gold Coast Criteria. was diagnosed with ALS. The total MRC score of the cases was between 40-100, with a mean of 80.2 ± 13.5; upper motor neuron score ranged from 1 to 16, with a mean of 11.2 ± 4.5. In addition, the total ALSFRS-R score at the time of inclusion in the study was calculated, and the obtained scores ranged from 17 to 45, with a mean of 36.6 ± 6.9. Electrophysiologically, CMAP recording from 2 muscles (APB and ADM), H reflex from 7 upper-lower extremity muscles (bilateral soleus and unilateral ADM, APB, EDC, FCR and AH) of patients and controls were evaluated clinically together with neurological examination, and Finally, MEP examination was performed from bilateral APB-TA with both cortical and radicular stimulation. Fifteen of 52 patients were using riluzole at the time of enrollment (duration of use > 1 month). Soleus H reflex was obtained in 43 (82.7%) of 52 patients and in all 20 controls (100%) by recording from the side where the complaint started. In unilateral non-soles muscles, 3 (5.8%) patients had APB, 5 (9.6%) EDC, 12 (24.5%) FCR, and 3 ( 5.8% H-reflex response was obtained from AH, while H-reflex response could not be obtained from ADM. In normal cases, the H reflex could not be obtained from the muscles except soleus at all. While the H reflex was pathological in 15 of 52 ALS cases, all of them also had MEP pathology. The mean value of the Hmax /Mmax ratio in the patient group was 0.42 ± 0.28; When the controls were obtained as 0.28 ± 0.33, a statistically significant difference was detected when these two groups were compared; There was no significant difference between the H and M soleus threshold values. While bilateral APB and TA MEP responses all controls, the rates of obtaining it in patients were 53.8% - 55.8% with cortical stimulation from right-left APB, respectively; 84.6% - 88.5% were obtained with radicular stimulation. When the patients and controls were compared in line with the general results, the main findings were found to be prolongation in central motor conduction time (CMCT), change in MEP amplitude and unresponsiveness as TMS pathology. When CMCT was taken into account, 48 of 52 cases supported upper motor neuron involvement according to TMS. As a result, we suggest that TMS, which is performed symmetrically on the upper and lower extremities and evaluated in detail with cortical/radicular stimulation, can contribute to the diagnosis with a value close to 95%, as the clinical neurophysiological counterpart or marker of upper motor neuron involvement in ALS cases. Although the extension of the H reflex was different from the normal ones in upper motor neuron involvement, it did not contribute to TMS in the diagnostic sense.