In an Italian population of 275 unrelated men affected by adult-onset sporadic progressive cerebellar ataxia, the authors found six patients carrying an FMR1 gene premutation. Age at onset (range, 53 to 69 years) and clinical-neuropathologic findings were consistent with the fragile-X tremor ataxia syndrome (FXTAS), although tremor was not as common as previously described. FXTAS accounted for 4.2% of the cases diagnosed at >50 years, suggesting that it is a frequent genetic cause of late-onset sporadic ataxia.

There is evidence of oxidative injury in postmortem brain, spinal cord, and CSF of patients with sporadic amyotrophic lateral sclerosis (SALS patients). We investigated the oxidative metabolism and calcium homeostasis in peripheral blood lymphocytes from such patients and did not find statistical differences in the basal oxygen consumption rate (QO2), cytochrome c oxidase activity, catalase activity, and lactate production. However the increase in QO2, induced by an uncoupler of oxidative phosphorylation, was depressed and the basal (resting) level of free cytosolic calcium ([Ca2+]in) was higher in lymphocytes from SALS patients (p < 0.01). Further increase in free [Ca2+]in challenged by a K+ channel blocker or by an uncoupler of oxidative phosphorylation was similar in SALS and control lymphocytes. The results show that systemic changes consistent with the presence of mitochondrial and of calcium metabolism dysfunction are present in SALS.

In 31 patients with probable Alzheimer's disease (AD), 19 with probable vascular dementia (VaD) and 20 with Possible AD and Possible VaD, cerebrospinal fluid (CSF) tau levels hyperphosphorylated at threonine 181 (Ptau) were measured by ELISA. Thirty-six age-matched subjects were used as controls. The severity of the cognitive decline was assessed at the time of CSF analysis and after a 12-month follow-up. The groups had comparable age, degree of cognitive impairment and disease duration; these parameters were not related to P-tau levels. P-tau discriminated between demented patients and controls, but no significant difference emerged between AD and the other groups. By contrast, higher P-tau values were found to predict, independently of the clinical diagnosis, a more rapid evolution of cognitive decline. Whether these findings are due to a lack of CSF P-tau specificity or to the low reliability of clinical and radiological criteria remains unclear. P-tau may be useful in the evaluation of disease evolution, by predicting the rate of cognitive decline.

An impairment of cholinergic and somatostatinergic neurotransmission have been reported in dementia. Both acetylcholine and somatostatin are involved in the regulation of growth hormone (GH) secretion. The effects of GH-releasing hormone (GHRH) 1–44 on GH release have been studied before and after the pretreatment with pyridostigmine or pirenzepine in subjects with senile dementia of the Alzheimer type, multi-infarct dementia and mixed dementia. The data have been compared with those obtained in an age-matched healthy control group. The GH response to GHRH is similar in the patients and in the controls, though the peak occurrence is significantly delayed in dementia. The cholinesterase inhibitor pyridostigmine enhances significantly the GH response to GHRH in both groups. The responses obtained in demented subjects are significantly larger than those found in the controls. Pirenzepine, a muscarinic receptor blocker, inhibits the GHRH effect on GH secretion in both groups. The findings may be interpreted in terms of an underlying impairment of the hypothalamic cholinergic neurotransmission, with an acetylcholine receptor supersensitivity that becomes apparent when the cholinergic tonus is enhanced by the inhibition of cholinesterase by pyridostigmine. No significant differences, due to the type of dementia, have been observed.