5/7/2023 0 Comments Aica vs pica syndrome![]() Patients with abnormal cVEMPs are more likely to have caloric paresis or sensorineural hearing loss compared with those with normal cVEMPs. About half of patients with AICA infarctions show abnormal cVEMPs in response to click stimulation of the ipsilesional ear ( Ahn et al., 2011). Since patients with AICA infarction and normal caloric responses produce contralesional ocular torsion only ( Lee et al., 2008), damage to peripheral vestibular structures appears to play a crucial role in determining the direction of the OTR and SVV tilt in AICA infarctions ( Lee et al., 2008). AICA infarctions usually cause ipsiversive OTR and tilt of the SVV ( Lee et al., 2005, 2008). However, multiple risk factors for stroke and profound hearing loss predicted a poor outcome for recovery of hearing loss ( Kim et al., 2014a). The hearing loss and caloric paresis detected during the acute phase of AICA infarction usually recover over time ( Lee et al., 2011b Kim et al., 2014a). Thus, careful evaluation of HSN may provide clues for diagnosis of AICA infarction in patients with acute audiovestibular loss ( Huh et al., 2013). Therefore, detection of central lesions may require additional tests, such as horizontal head shaking, which detected central patterns of HSN in 3 of the 5 patients with AICA infarction and negative HINTS ( Huh et al., 2013). Indeed, the HINTS failed to detect central lesions in 5 of 18 patients with AICA infarction ( Huh et al., 2013). The HINTS (negative HIT, direction-changing nystagmus, and skew deviation), the most useful bedside tool to detect central vestibulopathy, may not be sufficiently robust to detect central lesions in AICA infarction, since the HIT is mostly positive in this disorder ( Huh et al., 2013 Newman-Toker et al., 2013b Choi et al., 2014a). HSN is also common with both peripheral and central patterns. Asymmetric bidirectional GEN, frequently mimicking Bruns’ nystagmus, is found in 43% of patients ( Lee et al., 2009). In AICA infarction, spontaneous nystagmus is predominantly horizontal and mostly beats away from the lesion side ( Lee et al., 2009). (2015b), with permission from Springer Science and Business Media. ![]() A patient with infarction in the territory of right anterior inferior cerebellar artery ( A) shows ipsiversive ocular torsion ( B), contralesional spontaneous nystagmus ( C), gaze-evoked nystagmus ( D), ipsilesional caloric paresis ( E), ipsilesional hearing loss ( F), decreased amplitude of the ipsilesional cervical vestibular-evoked myogenic potentials (VEMPs, G), and absent responses of ocular VEMPs during ipsilesional ear stimulation ( H). Ipsilateral conjugate gaze palsy may reflect infarction of the flocculus (see Table 2-5).įig. 189, 192, 193 Other features include vomiting, ipsilateral facial numbness, facial palsy, Horner syndrome, and contralateral loss of pain and temperature. Usual symptoms are nausea, vertigo, tinnitus, and hearing loss. The findings reflect involvement of the peripheral nervous system and CNS structures at the cerebellopontine angle. Syndrome of Anterior Inferior Cerebellar Artery Occlusion Comparison of Anterior Inferior Cerebellar Artery and Superior Cerebellar Artery InfarctsĪICA infarcts most consistently involve the lateral pons and the middle cerebellar peduncle, 191 often sparing the cerebellum itself, in contrast to SCA infarction, which predominantly affects the cerebellum, sparing the brainstem. When the PICA is missing, the territory of the AICA includes the territory of the PICA (see Fig. Its cerebellar territory borders on and is reciprocal in size with the territories of the SCA and PICA. 190Īs seen ventrally, the AICA irrigates a triangle with its base toward the midline, where it abuts on the paramedian zone irrigated by perforators from the BA and VA (see Fig. The AICA acts as the artery of the cerebellopontine angle. Typically, the AICA also gives rise to an IAA that enters the internal acoustic meatus (see internal auditory artery (IAA), infra). ![]() The AICA runs laterally to irrigate the ventrolateral pons, essentially the caudal part of the middle cerebellar peduncle, which is its core distribution the spinothalamic tract the trigeminal, facial, vestibular, and cochlear nuclei the roots of CN VII and VIII and the ventral parts of the cerebellum, including the flocculus. With a left dominant AICA, the ipsilateral VA and PICA are usually hypoplastic (see Fig. ĪICA dominant on the left and PICA dominant on the right.Įqual right and left origins from the BA, with a major anastomosis between the AICA and the PICA ( Fig.The AICA runs laterally, just caudal to CN VI. The AICA arises from the BA, just rostral to the union of the VAs to form the BA.
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