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العنوان
Assessment of Central Vestibular Pathway in Patients with Vestibular Migraine /
المؤلف
Fawzy, Amira Mohamed.
هيئة الاعداد
باحث / أميره محمد فوزي
مشرف / هشام محمود سامي
مشرف / رفيق محمد عبد القادر
مشرف / داليا فهيم محمد
الموضوع
Neurology.
تاريخ النشر
2021.
عدد الصفحات
137 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
الطب
تاريخ الإجازة
1/1/2021
مكان الإجازة
جامعة المنيا - كلية الطب - طب السمع والاتزان
الفهرس
Only 14 pages are availabe for public view

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Abstract

The current study included 3 groups. group I was the group of VM patients, which included 39 patients with VM. Patients with VM were selected according to the IHS criteria (Zhang et al., 2016). group II was the control group, which included 20 healthy volunteers.
The current work was designed to facilitate a complete set of VM diagnostics, through performing the vHIT examining the three SCCs, the cervical and ocular VEMP examining the superior and inferior vestibular nerve functions and otolith function, and fixation suppression test using the caloric stimulation examining the vestibulo-cerebellar tract in patients with VM.
The specific aims of the current work were:
1-Assessment of the central vestibular involvement versus peripheral contribution in patients with VM. This aim was addressed by performing VNG, vHIT, oVEMP and cVEMP tests.
2-To assess the function of vestibulo-cerebellar tract in VM patients, and this aim was addressed by measuring the power of this tract in the suppression of the caloric nystagmus, through recording the FSI at the start of fixation, and the latency of this tract to do a 50% fixation suppression.
In control group, The control group consisted of 20 subjects; 8 males (38%) and 12 females (62%). The cVEMP was intact in all ears of the control group (100%). The P1-N1 VEMP amplitude ranged between 7.64µv and 442.99µv, the AR ranged between 3.35% and 29.57%. The P1 latency ranged between 10.58ms and 21.00ms, the N1 latency ranged between 16.42ms and 27.92ms, the IAL difference of P1 ranged between 0.59ms and 0.83ms, the IAL difference of N1 ranged between 0.33ms and 2.08ms. The oVEMP was intact in (100%) of control subjects, the P1-N1 VEMP amplitude ranged between 1.47µv and 28.07µv, the AR ranged between 1.28% and 29.44%, The P1 latency ranged between 12.42ms and 18.58ms, The N1 latency ranged between 8.5ms and 13.33ms, the IAL of P1 ranged between 0.41ms and 0.75ms. The IAL of N1 ranged between 0.08ms and 0.33ms.
The FSI was intact and more than 50% in all cases. FSI just in the start of fixation was ranged between 18.67% and 95.63% The latency of FSI to do a 50% suppression ranged between 0.07 sec and 1.48 sec. As regard the SPV, it was ranged between 10.40 degrees/sec and 55.10 degrees/sec.
The VOR gain in the posterior canals ranged from 0.64 to 1.35, while the VOR gain in the anterior canals ranged from 0.74 to 1.42. The VOR gain in the lateral canals ranged from 0.85 to 1.26.
In VM group, the VM group consisted of 39 patients. There were 12 males (24%) and 27 females (76%). Regarding the cVEMP, (69%) patients had bilateral intact cVEMP, (5%) had absent bilateral cVEMP, and (26%) had unilateral absent cVEMP. The P1-N1 VEMP amplitude ranged between 5.25 µv and 397.37µv The AR ranged between 2% and 70%. The P1 latency ranged between 9.75ms and 29.51ms. The N1 latency ranged between 14.75ms and 32.67ms, the IAL difference of P1 ranged between 0.92 and 5.5ms, the IAL difference of N1 ranged between 0.8 and 1ms. As regard oVEMP, (82%) patients had bilateral intact oVEMP, (3%) had absent bilateral oVEMP, and (15%) had unilateral absent oVEMP. The P1-N1 VEMP amplitude ranged between 0.19 µv and 36.7 µv. The AR ranged between 2% and 59%. The P1 latency ranged between 10.92ms and 20.50ms. The N1 latency ranged between 8.75ms and 15.92ms. The IAL difference of P1 ranged between 10.9ms and 20.5ms. The IAL difference of N1 ranged between 8.75ms and 15.9ms. The FSI was intact and more than 50% in all cases. FSI just in the start of fixation was ranged between 10.3% and 97%. The latency of FSI to do a 50% suppression ranged between 1.02 sec and 1.61 sec. Regarding the slow phase velocity, it was ranged between 11.2 degrees/sec and 112 degrees/sec. The VOR gain in the posterior canals ranged from 0.55 to 1.48, while the VOR gain in the anterior canals ranged from 0.4 to 1.26. In contrast, the VOR gain in the lateral canals ranged from 0.77 to 1.29. So vHIT gain is normal in all SCCs.
In comparison to control group, using 500 Hz TB, all the control ears had intact cVEMP, while 82% of ears of VM patients had intact cVEMP and 18 % of ears of VM patients had absent cVEMP. Such results was statistically significant. Moreover, There was statistically significant difference between VM group and control group as regard the P1-N1 amplitude, AR, P1 latency, N1 latency.
Regarding the oVEMP, all the control ears had intact oVEMP, while 90% of ears of VM patients had intact cVEMP 10% of ears of VM patients had absent oVEMP. Such results was statistically significant. Moreover, There was statistically significant difference between VM group and control group as regard the P1-N1 amplitude, P1 latency, N1 latency. The only significant difference between the two groups was in the AR.
Comparing the both groups as regarding the vestibulo-cerebellar tract function, there was a statistically significant difference between the VM patients and the control subjects, as regarding FSI at the start. But there was no statistically significant difference between the both groups as regards the total latency of the vestibulo-cerebellar track to do 50% fixation. In addition, there was a statistically significant difference between the both groups, regarding the total SPV of the caloric response
On the other hand. There was no statistically significant difference between the control group and VM group regarding the gain of the lateral, posterior canals in the vHIT. Still, there was a significant difference between both groups regarding the gain of the right anterior SCC, with no covert or overt saccades.
Comparison between the VM patients with vertical nystagmus and VM patients without vertical nystagmus
There was a significant difference between the VM group with vertical nystagmus and the VM group without vertical nystagmus regarding cVEMP presence vs absence, but no significant difference between the both groups regarding the other cVEMP parameters.
In addition, There was a significant difference between the VM group with vertical nystagmus and the VM group without vertical nystagmus regarding oVEMP presence vs absence, but no significant difference between the both groups regarding the other oVEMP parameters except the IAL differences of P1 and N1 latencies.
Regarding the FSI at the start of fixation, or the latency of vestibulo-cerebellar tract to do 50% fixation, there was no statistical significant difference between the VM patients who had vertical nystagmus and the VM patients without vertical nystagmus. However, there was a statistically significant difference between the two groups, regarding the SPV of the caloric response.
For vHIT, There was no statistically significant difference between the VM group with vertical nystagmus and the VM group without vertical nystagmus, regarding either the gain of the lateral, anterior and posterior SCCs, or presence of covert or overt saccades
In conclusion
The VM proved to be a mixed disorder, affecting both peripheral and central vestibular systems. Our study showed central affection more than peripheral affection in VM, as revealed from lower FSI than that of the control subjects, also the hyperactive caloric response in the majority of VM patients, as a result from decreased cerebellar inhibition of the caloric nystagmus, this reflects affection of the vestibulo-cerebellar tract in VM patients. And this supports our hypothesis that the power of this tract is not the same as normal subjects, so that that the VM patients feel dizzy after caloric stimulation, and the degree of SPV is greater than that of control subjects.
Recommendation and future suggestions
1- More detailed investigations about the function of vestibulo-cerebellar tract, in disorders other than VM, to collect more data about its pathology in different vestibular disorders.
2- Giving the VM medications for those patients who had affected VEMPs amplitudes, latencies or even absent responses. And following them up , trying to repeat the cVEMP and oVEMP to collect more data.
3- Researching on the pathology in cVEMP and oVEMP in VM patients with vertical positional nystagmus.
4-Doing more researches on vHIT in other central or mixed vestibular disorders.