Polymicrogyria in Standard Poodles

Abstract

Background: Polymicrogyria is a disorder of cerebrocortical migration resulting in increased numbers of small, disorganized gyri. This disorder occurs in Standard Poodles and in cattle.Objectives: To describe the clinical, electroencephalographic, imaging, and histopathologic features in poodles with polymicrogyria.Animals: Five Standard Poodles with histologically confirmed polymicrogyria. Methods: Retrospective case series. Cases were obtained by personal communication with 1 of 2 authors (TJVW, DPO). Results: All dogs had cortical blindness and other neurologic abnormalities including gait and behavioral changes. Magnetic resonance imaging of 3 dogs showed multiple disorganized gyri, which were especially apparent on T2-weighted dorsal plane images. Electroencephalogram (EEG) of 1 dog revealed epileptiform discharges, including both spike and spike and wave discharges with voltage maximum potentials over the parietal/occipital region. The EEG supported that the repetitive behavior displayed by the dog was a complex partial motor seizure. One dog had concurrent hydrocephalus. All dogs had occipital lobe involvement and 2 dogs had involvement of other lobes.Clinical Importance:The cases presented here demonstrate a larger age range (7 weeks to 5 years) and a decreased frequency of associated hydrocephalus when compared with the previous report.

A Digital Atlas of the Dog Brain

“…Individual differences in brain structure as assessed by different imaging modalities, such as cortical thickness, or diffusion tensor imaging [54], may be related to normal variations of behavior or one of many disease states. Indeed, the canine is a valuable model system for many neurological diseases, including epilepsy [55]; cortical malformations such as lissencephaly [56], [57] and polymicrogyria [58], [59]; dementia [60], [61]; and focal lesions [62], [63]. Given the good registration of high-resolution anatomy with a head model, the atlas can be used to guide source localization of EEG recording in the dog [64].…”

Magnetic Resonance Imaging of Intracranial Malformations in Dogs and Cats

“…Polymicrogyria is a rare malformation of the cerebrum characterized by an excessive number of small, histologically anomalous gyri 3,50 . In humans, polymicrogyria may occur following intrauterine ischemia or in utero infection 2,50,51 . Polymicrogyria has been reported in Standard Poodles, in which it is suspected to have a hereditary basis 50,51 .…”

“…In humans, polymicrogyria may occur following intrauterine ischemia or in utero infection 2,50,51 . Polymicrogyria has been reported in Standard Poodles, in which it is suspected to have a hereditary basis 50,51 . Polymicrogyria may be generalized or lobar in distribution but has been consistently found in the occipital lobes of affected dogs 51 .…”

“…Polymicrogyria has been reported in Standard Poodles, in which it is suspected to have a hereditary basis 50,51 . Polymicrogyria may be generalized or lobar in distribution but has been consistently found in the occipital lobes of affected dogs 51 . Affected dogs also have thinning of the cortical mantle and variable lateral ventriculomegaly 50,51 .…”

Electroencephalography as a diagnostic technique for canine neurological diseases

“…In humans with this disease, up to 41.5%-55% have normal EEG and the changes found are not disease-specific (43). In the presented case, the occurrence of IED increased the suspicion that untypical behaviour of circling and lip smacking were likely to be complex partial motor seizures (24).…”