Systemic involvement in adult-onset leukoencephalopathy with intracranial calcifications and cysts (Labrune syndrome) with a novel mutation of the SNORD118 gene

BACKGROUND AND PURPOSE

Although Labrune syndrome is a well-known disorder characterized by a typical neuroradiological triad, namely leukoencephalopathy, intracranial calcifications and cysts, there are no reports of systemic involvement in this disorder. This paper attempts to describe a peculiar clinical manifestation related to a novel mutation in the SNORD118 gene.

METHODS

Clinical examination, brain and total-body imaging, and neurophysiological and ophthalmological investigations were performed. Amplification of the SNORD118 gene and Sanger sequencing were integrated to investigate potential causative mutations.

RESULTS

A 69-year-old woman, with a long history of episodes of vertigo and gait imbalance, was referred to our hospital for progressive cognitive and motor deterioration. Computed tomography and magnetic resonance imaging disclosed diffuse bilateral leukoencephalopathy in periventricular and deep white matter, widespread calcifications and numerous cysts in the brain, liver, pancreas and kidneys. The genetic analysis revealed two biallelic variants in the SNORD118 gene, one of which is novel (n.60G>C).

CONCLUSIONS

This is the first report of adult-onset Labrune syndrome with an unusual systemic involvement presenting a novel mutation in the SNORD118 gene.

“What do you know about Ho Chi Minh?” Italian norms of proper name comprehension

Ninety-eight healthy participants were examined with a new test of Famous Name Comprehension which, in the framework of a serial model of person processing, sequentially assessed Name Recognition (i.e., the ability to classify items as familiar or unfamiliar) and Person Identification (i.e., the ability to provide biographical knowledge of recognised items). Names were presented in a written format. A perfectly equivalent face version of the test allowed a comparison of familiarity and identification of people from name and from face input. Furthermore, the effect of the "age" of the items, i.e. the time elapsed from the presumed first exposure to the stimulus to the time of testing, was also investigated. Normative data are provided. Education was the only significant variable for recognition, while education, age and gender turned out to be significant for identification. Recognition was significantly better with name than with face input, while on identification names and faces did not differ significantly. "Oldest" items were both recognised and identified significantly worse than recent ones. The results of face-name comparison are interpreted in terms of the different opportunities to be exposed to names and faces, the relevance of visuoperceptual attributes linked to faces and the evidence of shared knowledge from different inputs. The relative advantage of recent celebrities supports the semantic characterisation of knowledge of famous people.

Temporal gradients for media–mediated memory: Italian norms

Temporal gradient (TG), i.e., differential recall of recent and old memories, is a well known feature of amnesia. A recent study provided evidence of a classical TG for media-mediated events in elderly healthy people, showing that they recall remote events significantly better than recent ones, while a reverse TG, i.e., better recall of more recent events, was demonstrated in younger normal subjects. In the present study we present normative data which, using the same test, allow evaluation of TG in single cases and their qualification as classical or reverse. The normative procedure was also applied to a small sample of subjects with probable Alzheimer's disease or mild cognitive impairment. Norms for TG may be helpful not only to assess healthy people's performance, but also to judge any apparent TG in pathological subjects.

Who is who: Italian norms for visual recognition and identification of celebrities

Age-, education- and sex-adjusted norms are provided for two new neuropsychological tests, namely (i) Face Recognition (guess of familiarity) and (ii) Person Identification (biographical contextualisation). Sixty-three pictures of celebrities and 63 of unknown people were selected following two interwoven criteria(1): the realm of their celebrity (i.e., entertainment, culture and politics) and the period of celebrity acquisition (i.e., pre-war, post-war and contemporary). Both media- and education-dependent knowledge of celebrity were considered. Ninety-eight unpaid healthy participants aged between 50 and 93 years and with at least 8 years of formal education took part in this study. Reference is made to serial models of familiar face/persons processing. Recognition is held to tackle the activity of Personal Identity Nodes (PINs) and identification of the Exemplar Semantics Archives. Given the seriality of the reference model, the Identification Test is embedded in the Recognition test. This entailed that only previously recognised faces were employed to achieve norms for identification.

?What do you remember about Chernobyl?? A new test of memory for media?mediated events

We devised a new test for assessing remote memory for media-mediated events, i.e. events that are reported by and known through the media. The test consists of a verbal questionnaire covering famous events that occurred over a long period of time, from 1976 to 2000, specifically designed for use with the Italian population. A free recall procedure was adopted which makes use of progressive cues. The test can be easily updated for inclusion of future events. Normative and test-retest reliability data are presented. The test provides a new tool for assessing media-mediated memory whenever an extensive assessment of retrograde memory performance is required, both in normal people and in brain-damaged patients.

Verbal learning strategies in Parkinson's disease

Word-list learning was studied in patients with Parkinson's disease (PD) and normal control (NC) participants by means of the selective-reminding procedure of H. Buschke and P. A. Fuld (1974) in 3 learning conditions using semantically unrelated items; semantically related items, whose implicit categorical structure had to be spontaneously guessed; and semantically related items, whose explicit categorical structure was known in advance. The PD patients displayed poor learning in all 3 conditions. To identify the functional locus of the PD patients' deficits, the authors performed a stochastic Markov chain analysis, which allowed individual measurements of encoding, retrieval, and category clustering abilities. PD patients were never significantly impaired in encoding word engrams; their impairment was confined to automatic and intentional retrieval and to the ability to benefit from explicit semantic clues.

Verbal learning strategies in Parkinson's disease

Word-list learning was studied in patients with Parkinson's disease (PD) and normal control (NC) participants by means of the selective-reminding procedure of H. Buschke and P. A. Fuld (1974) in 3 learning conditions using semantically unrelated items; semantically related items, whose implicit categorical structure had to be spontaneously guessed; and semantically related items, whose explicit categorical structure was known in advance. The PD patients displayed poor learning in all 3 conditions. To identify the functional locus of the PD patients' deficits, the authors performed a stochastic Markov chain analysis, which allowed individual measurements of encoding, retrieval, and category clustering abilities. PD patients were never significantly impaired in encoding word engrams; their impairment was confined to automatic and intentional retrieval and to the ability to benefit from explicit semantic clues.

The nature of the disorder underlying the inability to retrieve proper names

Two patients with the syndrome of proper name anomia were investigated. Both patients were only able to produce around 50% of the names of contemporary celebrities, but performed significantly better on a task calling for naming of historical figures. The names of relatives and friends were spared in one patient, while the other retrieved names of people known since childhood much better than those of people familiar to him since the age of 25. Geographical names, names of monuments and masterpieces were preserved. The above dissociations are taken to imply that in moderately impaired patients, a temporal gradient effect concurs to modulate the severity of the naming block. A similar impairment was found in both patients when they attempted to retrieve or relearn familiar telephone numbers. This finding suggests that the core of the disorder resides in the inability to gain access to words used to identify a single entity, regardless of whether they belong to the class of proper or common names.

Tactile morphagnosia secondary to spatial deficits

A 73-year old man showed visual and tactile agnosia following bilateral haemorrhagic stroke. Tactile agnosia was present in both hands, as shown by his impaired recognition of objects, geometrical shapes, letters and nonsense shapes. Basic somatosensory functions and the appreciation of substance qualities (hylognosis) were preserved. The patient's inability to identify the stimulus shape (morphagnosia) was associated with a striking impairment in detecting the orientation of a line or a rod in two- and three-dimensional space. This spatial deficit was thought to underlie morphagnosia, since in the tactile modality form recognition is built upon the integration of the successive changes of orientation in space made by the hand as it explores the stimulus. Indirect support for this hypothesis was provided by the location of the lesions, which could not account for the severe impairment of both hands. Only those located in the right hemisphere encroached upon the posterior parietal cortex, which is the region assumed to be specialised in shape recognition. The left hemisphere damage spared the corresponding area and could not, therefore, be held responsible for the right hand tactile agnosia. We submit that tactile agnosia can result from the disruption of two discrete mechanisms and has different features. It may arise from a parietal lesion damaging the high level processing of somatosensory information that culminates in the structured description of the object. In this case, tactile recognition is impaired in the hand contralateral to the side of the lesion. Alternatively, it may be caused by a profound derangement of spatial skills, particularly those involved in detecting the orientation in space of lines, segments and complex patterns. This deficit results in morphagnosia, which affects both hands to the same degree.

Learning and forgetting processes in Parkinson's disease: a model-based approach to disentangling storage, retention and retrieval contributions

Learning and forgetting a prose passage was studied in 20 patients with Parkinson's disease and in 20 normal control subjects by means of stochastic models, with the aim of identifying the learning and retaining abilities that are affected by Parkinson's disease. Results suggested that Parkinson's disease patients are impaired in developing automatic processing both during learning and retaining, while functions that require active attention are spared. The automatic/intentional dissociation, which is the hallmark of motor disturbance in Parkinson's disease, extends to memory abilities, and, on the grounds of neuroanatomical, neurochemical and neurophysiological correlates, suggests that the memory deficit in Parkinson's disease may be contingent on a dysfunction of the medial prefrontal-cingulate cortex.

Associative agnosia and optic aphasia: qualitative or quantitative difference?

We report a patient who, following the partial removal of a tentorial meningioma, suffered a hematoma in the left occipital lobe, which was resected. He showed severe anomia for visually presented stimuli, while naming was normal when they were presented in the tactile, auditory and verbal modality. His performance on visuo-perceptual tests, not requiring meaning identification, provided evidence that he was able to access the stored representations of stimuli. When recognition was assessed with non-verbal tasks, a mixed pattern of findings emerged and the patient showed features of both associative agnosia and optic aphasia. He was severely impaired in producing pantomimes in response to pictures, but only marginally impaired in sorting figures from the same superordinate category into fine-grained subcategories. He performed within the normal range on an associative task, in which the distractors bore no semantic relation to the target, but made many errors when the distractors and the target were semantically related. We propose that the interpretation advanced by Coslett and Saffran (Brain, 1989) for optic aphasia also holds for associative agnosia and argue that both syndromes reflect the impaired access of structured representations to left hemisphere semantics, but differ in terms of the degree of compensation provided by the semantic resources of the right hemisphere. Since the anatomical basis of the two syndromes may be very similar, we submit that what makes the difference is the semantic potential of the patient's right hemisphere.

Visual illusion and action

The role of allocentric cues on movement control was investigated in the present study. Pointing movements directed to the more distant vertex of closed and open configurations of the Muller-Lyer illusion, as well as to the vertex of control lines, were studied in four experimental conditions. In the first (full-vision condition) subjects saw both stimulus and their hand before and during movement, in the second (non-visual feedback condition) they saw the stimulus, but not their hand during movement. In the two remaining conditions (no-vision conditions) vision of the scene and the hand was precluded. Pointing was executed 0 sec (no vision 0 sec delay condition) or 5 sec (no-vision 5 sec delay condition) after the light was switched off. The Muller-Lyer illusion affected pointing kinematics with respect to the control lines. Subjects undershot and overshot the vertex location, respectively, of the closed and open configuration. Correspondingly, the entire kinematics were changed. The main result was, however, a gradually increasing effect of the perceptual illusion when pointing was executed from memory compared to the full-vision condition. These data are discussed according to the hypothesis that the system underlying visual perception in the allocentric frame of reference and that involved in motor action can functionally interact. The strength of this interaction depends upon the efficiency of the egocentric frame of reference by which motor actions are constructed.

On orienting the hand to reach and grasp an object

Subjects were required to reach and grasp a parallelepiped, the position, orientation and size of which were varied. The kinematics of reaching and grasping movements was studied in full vision and in no vision conditions. Both direction and movement amplitude of reaching were affected by object orientation. Conversely, both the time course of finger axis orientation and the angular displacement of the hand at wrist were influenced by object position. These results were not modified by the absence of visual control. Finger aperture during grasping was affected by both object size and orientation. This latter result was not due to a distorted size perception, as shown by a control matching experiment. Taken together, the results of the present study suggest the integration between distal and proximal components during reaching and grasping.

Unconscious updating of grasp motor program

Grasp modification during prehension movements was studied in response to slight variations of somesthetic information about object size. Three experiments were carried out. In experiment 1 eight subjects were required to reach and grasp an object whose size could either increase or decrease, whereas its visual image remained unmodified. The object size was changed during the experiment with uninformed subjects after a block of trials during which visual and somesthetic information were congruent. At the end of the experiment subjects were required to reproduce the size of the object with their fingers (matching test). Results showed that maximal grip aperture during prehension as well as finger aperture in the matching test were modified according to variation in object size, although no subject realized that the object had changed during the experiment. Grasp time was also altered by object size change. Greater and earlier adaptation in maximal grip aperture, as well as perturbation of grasp time, were observed for decrease than for increase in object size. However, complete compensation was never reached for both parameters. Constant confidence in vision could have prevented both complete compensation and conscious detection of object change. This was investigated in two additional experiments. In experiment 2 visual information was made unreliable by informing subjects about variation in grasped object size. This led to greater and earlier modification in maximal grip aperture than in experiment 1. Grasp time was kept almost constant regardless of size variation. In experiment 3 vision of the stimulus was prevented and no information on change in object size was given to subjects. The results of experiment 3 were similar to those of experiment 1, although modification in maximal grip aperture was larger for increase in object size. Correspondingly, grasp time was more affected by increase than by decrease in object size. The results of the three experiments suggest that kinematic parameters usually considered as dependent on object properties, such as maximal grip aperture, were modified in order to compensate perturbation of temporal parameters. This modification induced a "pragmatic" knowledge of object size (as showed by the results of the matching test), although awareness was not reached.