| This thesis is an investigation of transcranial magnetic motor evoked potentials (TMMEP), somatosensory evoked potentials (SSEP), spinal evoked potentials (SEP) and brainstem auditory evoked responses (BAER) for the assessment of descending motor and ascending sensory pathways throughout the central nervous system of Cavalier King Charles Spaniel (CKCS) dogs with and without magnetic resonance imaging (MRI) confirmed syringomyelia. Fifty CKCS dogs were assigned into one of four groups, A (neurologic abnormalities and MRI-confirmed SM), B (neurologic abnormalities and no evidence of SM on MRI), C (no neurologic abnormalities and MRI-confirmed SM), and D (normal neurologic examination and no evidence of SM on MRI). Group D served as the control population for data analysis.;There were no significant differences in mean latencies between groups A, B, C, and D for TMMEP, SSEP, SEP and BAER. There was, however, a significant linear association between severity of neurologic signs and syrinx size: the larger the syrinx, the more severe the neurologic signs. Additionally, dogs with SM affecting more than 28% of their spinal cord were more likely to exhibit neurologic signs.;The results of this study suggest that TMMEP, SEP, SSEP and BAER tests do not detect functional abnormalities of the central nervous system in CKCS dogs with and without SM.;Transcranial magnetic motor evoked potentials, SSEP, SEP, and BAER were performed on all dogs under sedation. Onset latencies were measured for TMMEP, SSEP, and SEP, and I-V interpeak latencies were measured for BAER. Dogs were anesthetized for brain and spinal cord MRI (cervical, thoracic, lumbar) including sagittal and transverse T2-weighted images. Transverse T2-weighted image sequences were acquired on all regions of the spinal cord affected with SM to measure syrinx size (mm2) at maximum diameter and area of the surrounding spinal cord in order to obtain an overall percentage of spinal cord affected by SM. |
