CNS aspergillosis in a patient with Crohn's disease on immunosuppressants: a case report.

Fungal infections of the central nervous system are an uncommon cause of rapid decline in consciousness. We describe the case of central nervous system aspergillosis in a patient on immunosupressants whose clinical course highlights the need for an aggressive approach to diagnosis.

Hypersociability in Williams syndrome: a role for the amygdala?

We read with great interest the paper of Riby et al. regarding atypical, unfamiliar face processing in Williams syndrome (WS; Riby, Doherty-Sneddon, & Bruce, 2008a). It offers considerable insight into the mechanism of facial perception in humans and a further elaboration of the hypersociability observed in patients with Williams syndrome. We would like to suggest that the neurologic mechanisms underlying the hypersociability in WS may be attributable to an impaired recognition of facial expressions of threat, a feature that localises to the amygdala.

Rating the approachability of faces in ALS.

BACKGROUND: Several groups have found that a significant percentage of patients with amyotrophic lateral sclerosis (ALS) have cognitive impairment. Here we investigate whether the amygdala, a temporal lobe structure, is affected by ALS. METHODS: We asked patients with ALS to judge the approachability of unfamiliar faces. We showed subjects 60 faces and asked, "If you were in a strange town at dusk, would you ask this person for directions to a hotel?" RESULTS: More than half of our patients had similar behavioral characteristics to patients with bilateral amygdala damage, approaching even faces that controls found unapproachable. This pattern was not associated with frontal lobe dysfunction on neuropsychological testing. DISCUSSION: Patients with amyotrophic lateral sclerosis (ALS) rated highly approachable faces similarly to controls but rated many faces approachable that controls deemed unapproachable. Like patients with amygdala damage, who show the same behavior, patients with ALS may not recognize the threat expressed through facial clues that raise concern in controls. Thus, more patients with ALS may have disease involvement outside of the motor cortex than previously suggested, manifesting as frontal lobe, temporal lobe, or frontal and temporal lobe dysfunction.

Neurologic, neuropsychologic, and electroencephalographic findings after European tick-borne encephalitis in children.

Tick-borne European early summer meningoencephalitis is believed to be a benign disease in childhood. The causative RNA virus is from the same family as the West Nile virus, and the respective clinical presentations have many similarities. We studied 19 German children who had suffered from tick-borne encephalitis virus meningitis or meningoencephalitis in an endemic area and compared them with 19 matched controls. Epidemiologic data were consistent with known features of tick-borne encephalitis infection in southern Germany. None of the children studied had severe neurologic or neuropsychologic sequelae. One child developed significant clinical depression shortly after the illness. Electroencephalograms (EEGs) from children with tick-borne encephalitis were significantly slower on follow-up than control EEGs. After tick-borne encephalitis, children had a higher likelihood of having an impairment of attention and psychomotor speed. Using the Touwen neurologic examination, after tick-borne encephalitis, children had lower scores than control children on 4 of the 10 subsystems. Owing to the small sample size, it was difficult to identify risk factors for and predictors of adverse outcomes.

Cognitive procedural learning in patients with fronto-striatal lesions.

Previous studies on the role of prefronto-striatal loop systems for cognitive procedural learning (PL) brought inconsistent results. To examine whether the integrity of the dorsolateral prefrontal loop is indispensable for normal cognitive PL, we examined the acquisition of cognitive skills in 35 patients with focal prefrontal lesions, focal caudate lesions, and Huntington's Disease (HD), and compared it with a control group. To examine the potential role of the processing demands made by the cognitive tasks, a set of tasks was applied whose acquisition places demand either on reasoning and problem solving, or on the establishment of fast and repetitive processing routines. The Pursuit Rotor task was also studied with the aim to re-examine earlier findings of a functional segregation of motor and complex prefronto-striatal loops. Deficits of cognitive and motor PL were found to be limited to certain tasks and groups. PL of one task, which demanded rapid, repetitive processing of visuo-spatial stimuli, was impaired in all patient groups. PL of two problem-solving tasks was impaired in patients with focal and degenerative caudate lesions only. None of the groups was impaired at PL of Mirror Reading, another task demanding rapid and repetitive visuo-spatial processing, and none was impaired in a fifth task of language skill. Deficits of motor learning were only observed in patients in whom the motor loop was affected. These results suggest that the dorsolateral prefronto-striatal loop is involved in the establishment of cognitive processing routines. The comparison of patients with and without caudate lesions suggests that disconnection of this circuit is critical. However, the normal acquisition of two cognitive tasks even in this group indicates that the integrity of the dorsolateral prefrontal loop is not mandatory for normal cognitive PL. We discuss these dissociations with regard to the demand profiles of the applied tasks and the locations of the lesions.

Semantic knowledge in patient H.M. and other patients with bilateral medial and lateral temporal lobe lesions.

We investigated the effects of damage to the medial temporal lobe (MTL) and anterolateral temporal cortex on semantic knowledge. We studied eight male controls, two patients with lesions limited to the hippocampal formation, three postencephalitic patients with extensive MTL lesions and variable damage to the lateral temporal cortex, and patient H.M. (whose lesion is limited mostly to the MTL, but who also has minimal damage to the anterolateral cortex). On 13 tests of semantic memory, patients with lesions limited to the hippocampal formation performed similarly to controls. Postencephalitic patients were mildly to moderately impaired on most tests. Patient H.M.'s performance was impaired on only a few tests and was less severely impaired overall than the three postencephalitic patients. A ranking of test scores showed a direct relationship between impairment and the extent of damage to lateral temporal cortex. These findings, and related findings from other studies, point to the importance of anterolateral temporal cortex for semantic knowledge. Patient H.M. performed uniquely in certain respects. For example, when providing definitions of objects, he made many grammatical errors. In contrast, the other patients with large MTL lesions made no more errors than those made by controls. Considering that H.M.'s lesion, both medially and laterally, is less extensive than the lesions in these other patients, it appears unlikely that his shortcomings in language production are related to his temporal lobe lesion.