1/3. Progranulin gene mutations associated with frontotemporal dementia and progressive non-fluent aphasia.frontotemporal lobar degeneration (FTLD) refers to a focal, non-Alzheimer form of cerebral degeneration that encompasses the distinct clinical syndromes of frontotemporal dementia (FTD), progressive non-fluent aphasia (PNFA) and semantic dementia. Some patients show tau-based pathological changes and in familial cases mutations have been identified in the microtubule-associated protein tau gene (MAPT) on chromosome 17q21. However, many cases are tau-negative, showing instead ubiquitin-immunoreactive (UBQ-ir) neuronal cytoplasmic inclusions and neurites, and in some familial cases UBQ-ir neuronal intranuclear inclusions of a lentiform appearance. Very recently, mutations have been identified in familial cases in the progranulin (PGRN) gene, also on chromosome 17q21. Clinical, pathological and molecular diversity within FTLD highlights the importance of careful examination of clinical-pathological-genetic relationships. This paper reports, for the first time, a clinico-pathological investigation of two FTLD families with PGRN mutations, and compares the clinical characteristics with those of patients studied in the department with MAPT mutations. The clinical profile associated with PGRN mutations constituted, in some patients, a prototypical picture of FTD and in others one of PNFA, both profiles occurring within the same family. patients with PGRN mutations exhibited phonological deficits, whereas in patients with MAPT mutations language abnormalities, when present in addition to the prominent behavioural disorder, take the form of semantic disturbance. The findings provide compelling evidence for the link between FTD and PNFA, while raising the possibility of identifiable clinical differences between FTLD patients with MAPT and PGRN mutations.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
2/3. Impaired grammar with normal fluency and phonology. Implications for Broca's aphasia.Extensive testing of grammatical function, including assessment of spontaneous language, inflectional morphology, ability to produce grammatical structures, syntactic comprehension and grammatical judgement, was carried out in 2 patients with large dominant frontal lobe lesions, including but not confined to, the third frontal convolution. Both patients were fluent and had normal articulation and phonological production and neither was agrammatic, suggesting that even very large frontal lesions do not produce Broca's aphasia and that language cortex proper is confined to the postcentral perisylvian region. Both patients were impaired in the use of more complex syntactic structures and one, who in addition had severe generalized impairment in frontal lobe function, also had impaired judgement regarding the use and placement of functors. These data provide further support for the dissociability of syntactic and morphological aspects of grammar in aphasic patients and, together with other studies, link these functions with the frontal lobe and the postcentral perisylvian cortex, respectively. The sparing of grammatical judgement in 1 patient, despite a very extensive lesion, suggests that very large portions of the frontal lobe are involved in grammatical function. The nature of frontal lobe function in syntax appears to be congruent with the role of the frontal lobes in other aspects of behaviour.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
3/3. The grammatical properties of mass nouns: an aphasia case study.A patient (F.A.) is described who, as a consequence of brain damage, shows an isolated deficit concerning the use, across a series of tasks, of the grammatical properties of mass/non-countable nouns. Her use of grammar is otherwise perfect. This behaviour dissociates from that of other patients who have severe grammatical difficulties, but do not show any impairment in the mass nouns tasks that F.A. fails. This case is thought to demonstrate how specific grammatical rules, that are said to be stored at the lemma level of lexical retrieval, are indeed independently represented and accessible.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |