Network Localization of Unconscious Visual Perception in Blindsight.

OBJECTIVE: Blindsight is a disorder where brain injury causes loss of conscious but not unconscious visual perception. Prior studies have produced conflicting results regarding the neuroanatomical pathways involved in this unconscious perception. METHODS: We performed a systematic literature search to identify lesion locations causing visual field loss in patients with blindsight (n = 34) and patients without blindsight (n = 35). Resting state functional connectivity between each lesion location and all other brain voxels was computed using a large connectome database (n = 1,000). Connections significantly associated with blindsight (vs no blindsight) were identified. RESULTS: Functional connectivity between lesion locations and the ipsilesional medial pulvinar was significantly associated with blindsight (family wise error p = 0.029). No significant connectivity differences were found to other brain regions previously implicated in blindsight. This finding was independent of methods (eg, flipping lesions to the left or right) and stimulus type (moving vs static). INTERPRETATION: Connectivity to the ipsilesional medial pulvinar best differentiates lesion locations associated with blindsight versus those without blindsight. Our results align with recent data from animal models and provide insight into the neuroanatomical substrate of unconscious visual abilities in patients. ANN NEUROL 2022;91:217-224.

When cognitive evaluation does not disclose a neurologic disorder: experience of a university behavioral neurology clinic.

OBJECTIVE: We examined clinical features, referral patterns, and diagnostic outcome of patients receiving cognitive evaluation in a behavioral neurology clinic who had no neurologic disorder. BACKGROUND: Cognitive complaints may indicate Alzheimer Disease (AD) or many other conditions. Accurate early evaluation of these complaints is critical, and appropriate subspecialty clinic referral has public health policy implications. METHOD: This retrospective medical records review included 342 consecutive patients seen at the Neurobehavior Clinic of the University of Colorado Hospital from July 2006 through June 2008. All patients received an initial diagnosis by a clinic attending and subsequent consensus diagnosis by 3 subspecialists board certified in Behavioral Neurology & Neuropsychiatry. RESULTS: Among the 342 patients, 68% had a neurologic disorder, the most common of which was probable AD (17%). The remainder had nonneurologic diagnoses: 20% had a psychiatric diagnosis, 7% had no neuropsychiatric disorder, and 5% had a medical diagnosis. Of those with nonneurologic diagnoses, 65% were referred by primary care providers, and the most common symptom was memory loss (72%). In the psychiatric subgroup, depression was the most frequent diagnosis (56%). All normal individuals had concern about cognitive decline. In the medical subgroup, medication effect was the most frequent diagnosis (50%). CONCLUSIONS: Probable AD was the most common neurologic diagnosis, but 32% of the referred patients had no neurologic disorder, and most of these individuals had a psychiatric cause for cognitive complaints. These results highlight the need for policies promoting more effective use of subspecialty clinics dedicated to neurologic disorders of cognition.

Providing neurologic care in criminal systems and state mental hospitals.

As health care laws and payment structures change in the near future, neurologists may pursue other practice settings in which to provide care as a way to diversify their practice. Here we describe the challenges and opportunities involved with working in correctional and state mental hospital systems compared to a typical private practice: logistical challenges, patient and provider safety, patient characteristics, and cultural differences. Neurologists may take these factors into consideration when choosing whether to add this health care setting to their current practice.