| Name | Dario |
| Surname | Grossi |
| Institution | Università degli Studi della Campania Luigi Vanvitelli |
| dario.grossi@unicampania.it | |
| Address | Villa Camaldoli Foundation Clinic, Naples, Italy; Department of Psychology, University of Campania "Luigi Vanvitelli", Napoli, Italy |
We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.
Recent studies indicate that motor imagery is subserved by activation of motor information. However, at present it is not clear whether the sparing of motor efferent pathways is necessary to perform a motor imagery task. To clarify this issue, we required patients with a selective, severe de-efferentation (locked-in syndrome, LIS) to mentally manipulate hands and three-dimensional objects. Compared with normal controls, LIS patients showed a profound impairment on a modified version of the hand-laterality task and a normal performance on mental rotation of abstract items. Moreover, LIS patients did not present visuomotor compatibility effects between anatomical side of hands and spatial location of stimuli on the computer screen. Such findings confirmed that the motor system is involved in mental simulation of action but not in mental manipulation of visual images. To explain LIS patients' inability in manipulating hand representations, we suggested that the pontine lesion, both determined a complete de-efferentation, and affected a component of the motor system, which is crucial for mental representation of body parts, probably the neural connections between parietal lobes and cerebellum.
Acquired disorders of gesture imitation are amenable to treatment, but with poor generalisation toward gestures not included in the training program. We investigated the neural basis of this item-specific recovery in a patient with a slowly progressive posterior cortical atrophy, by means of an fMRI study comparing imitation of rehabilitated and not-rehabilitated gestures. Results suggested that in our patient gesture imitation recruited the mirror system and additional areas relevant to gesture analysis and preparation. Imitation of rehabilitated gestures activated the mirror neuron system, and also left dorsolateral prefrontal cortex and putamen, and the right anterior temporal cortex. This suggests that item-specific recovery was based on interaction of circuitry of imitation with neural systems involved in emotional and motivational processing.
The aim of this work was to determine the progression of cognitive impairment in Parkinson's disease (PD) patients with or without hallucinations. Two years after the first assessment, 36 PD patients were re-evaluated on standardized neuropsychological tests, including the Frontal Assessment Battery (FAB), and on rating scales for overall cognitive functioning, functional autonomy, behavioral disorders. Nine patients had hallucinations at baseline and endpoint assessments; 12 patients developed hallucinations during the follow-up; and 15 patients were hallucination-free throughout the study. Cognitive performance significantly declined in all three groups, but at endpoint assessment PD hallucinators scored significantly lower than nonhallucinators on phonological and semantic fluency tasks, immediate free recall and the go/no-go FAB subtest; moreover, they showed more severe apathy than nonhallucinators. Reduced phonological fluency at baseline (odds ratio [OR], 13.5; 95% CI: 1.34-135.98, P = 0.027) was the only independent predictor of onset of hallucinations after 2 years, whereas hallucinations (OR, 10.1; 95% CI: 1.94-51.54, P = 0.006) and poor phonological fluency (OR, 6.1; 95% CI: 1.04-35.03, P = 0.045) independently predicted development of diffuse cognitive impairment. We concluded that reduced verbal fluency scores may predict the onset of hallucinations, while hallucinations and poor phonological fluency may predict development of dementia in PD patients.
The ability of apraxic patients to perform gestures in everyday life is a controversial issue. In this paper, we aimed to evaluate the automatic/voluntary dissociation (AVD) in four patients affected by clinically relevant limb apraxia. For this purpose, we sampled different kinds of gestures belonging to patients' motor repertoire and then assessed their production in a testing session. Our experimental procedure consisted of two steps: in the first phase, we recorded gestures produced by patients in two natural conditions; in the second phase, we assessed production of correctly produced tool-actions, and of spontaneous non tool-actions and meaningless conversational (cohesive and beats) gestures under different modalities. AVD was observed for all types of gestures, albeit to different degree in single patients. The present findings demonstrate that the context provides strong bottom-up cues for the retrieval of motor patterns, while artificial testing conditions impose an additional cognitive load.
We report a patient with a right cortical and subcortical temporo-occipital lesion who showed spatial neglect mainly involving the left and the near peripersonal space. In drawing tasks the patient omitted the elements closer to him within each figure. A copying task with pairs of radially aligned line drawings demonstrated that the patient's radial neglect was based on within-object coordinates. This novel observation extends the egocentric-allocentric distinction to the radial dimension.
We report a patient who, following a focal ischemic lesion of the left basal ganglia, developed right hand micrographia characterised by progressive reduction of letter size during writing (progressive micrographia). The patient did not show relevant cognitive impairments, but achieved pathological scores in tests for verbal fluency, and cognitive flexibility and monitoring. A systematic investigation of the writing performances demonstrated that micrographia showed a clear length effect in whatever writing style or task, while it was not observed in drawing, or in left hand writing to a comparable extent. Right hand progressive micrographia was not affected by a concurrent motor and cognitive load; instead, switching between two kinds of allographic responses and presenting one letter at a time in copying tasks reduced severity of micrographia significantly. These findings support the view that progressive micrographia in our patient could be ascribed to a defect in regulating the motor output on the basis of self-generated strategies. This conclusion would be consistent with neuroimaging evidence about the role of the basal ganglia in the control of motor sequencing, and could suggest that progressive micrographia might be associated with specific executive defects.
Subjective memory complaint is a self-reported memory impairment which affects elderly people. This problem does not interfere with daily living activities but could decrease quality of life. This study's purpose was to verify whether a specific, newly developed, autobiographical recall training could modify self-perception of memory of subjects with subjective memory complaint. Seven elderly subjects (4 women and 3 men; mean age 65.5 yr., SD=11) with such complaint, evidenced through a specific questionnaire, attended the training course and were prospectively assessed on standard neuropsychological tests, depressive symptomatology, and self-perception of memory. Self-perception of memory, as assessed by scores on a formalized questionnaire, improved significantly after the training, while depressive symptoms did not change. Neuropsychological performances were normal before and after the training, but a statistically significant improvement was observed only on the phonological fluency test. Thus the present pilot study suggested that the training may be effective in improving self-perception of memory and metamnestic capacity in elderly people with subjective memory complaints but not in changing subjects' depressive symptoms. This requires replication of this work with a much larger sample so statistical power is adequate.
We describe a follow-up study of a patient with a selective, progressive impairment of topographical orientation. The patient's topographical difficulties were evident only in unfamiliar surroundings at the beginning of the observation period but later on they were observed even at home. Serial neuropsychological tests demonstrated a progressive impairment of visuospatial abilities with sparing of the other cognitive domains; only at the last assessment, about six years after early disturbances and three years after the first evaluation, the patient developed the typical cognitive impairments of Alzheimer's disease (AD). This case represents a focal variant of AD not previously described and suggests that the neuronal pathways underlying spatial orientation may be selectively damaged by the degenerative process.