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Biomedical subjects

J F Connolly

Publications and source records attributed to J F Connolly.

At least 37 records · Page 2Linked to original sources
PubMed1999

Performance on WISC-III and WAIS-R NI vocabulary subtests assessed with event-related brain potentials: an innovative method of assessment.

Assessment of intellectual functions is essential for rehabilitative interventions with traumatic brain injury and stroke patients. However, many of these patients are difficult or impossible to assess because of aphasia and physical disabilities that prevent their performance on traditionally administered tests of mental functioning. We present normative evidence obtained from healthy individuals for the efficacy of a new method of assessing such patients using standardized and validated tests formatted for computer presentation and using direct measures of brain activity (event-related brain potentials, ERP) as the measurable response instead of verbal or motor behavior.

Aphasia↗
PubMed1999

Semantic cortical activation in dyslexic readers.

The combined temporal and spatial resolution of MEG (magnetoencephalography) was used to study whether the same brain areas are similarly engaged in reading comprehension in normal and developmentally dyslexic adults. To extract a semantically sensitive stage of brain activation we manipulated the appropriateness of sentence-ending words to the preceding sentence context. Sentences, presented visually one word at a time, either ended with a word that was (1) expected, (2) semantically appropriate but unexpected, (3) semantically anomalous but sharing the initial letters with the expected word, or (4) both semantically and orthographically inappropriate to the sentence context. In both subject groups all but the highly expected sentence endings evoked strong cortical responses, localized most consistently in the left superior temporal cortex, although additional sources were occasionally found in more posterior parietal and temporal areas and in the right hemisphere. Thus, no significant differences were found in the spatial distribution of brain areas involved in semantic processing between fluent and dyslexic readers. However, both timing and strength of activation clearly differed between the two groups. First, activation sensitivity to word meaning within a sentence context began about 100 msec later in dyslexic than in control subjects. This is likely to result from affected presemantic processing stages in dyslexic readers. Second, the neural responses were significantly weaker in dyslexic than in control subjects, indicating involvement of a smaller or less-synchronous neural population in reading comprehension. Third, in contrast to control subjects, the dyslexic readers showed significantly weaker activation to semantically inappropriate words that began with the same letters as the most expected word than to both orthographically and semantically inappropriate sentence-ending words. Thus, word recognition by the dyslexic group seemed to be qualitatively different: Whereas control subjects perceived words as wholes, dyslexic subjects may have relied on sublexical word recognition and occasionally mistook a correctly beginning word for the one they had expected.

Adult↗
PubMed1998

Hemispheric lateralization in preattentive processing of speech sounds.

Event-related magnetoencephalographic (MEG) responses to infrequently presented spoken deviant syllables [di] and [ba] among repetitive standard [da)]syllables were recorded in subjects who either attended to these stimuli in order to discriminate the [ba] syllables or ignored them while attending a silent movie. In both conditions, the deviant syllables elicited a mismatch response (MMNm, the magnetic counterpart of mismatch negativity), which was stronger in the left than in the right auditory cortex, indicating left-hemispheric dominance in speech processing already at a preattentive processing level.

Acoustic Stimulation↗
PubMed1998

Effect of altering the daily herbage allowance to cows in mid lactation on the composition, ripening and functionality of low-moisture, part-skim Mozzarella cheese.

Milk was collected from three spring-calving herds, on different daily herbage allowances (DHA) of perennial rye-grass (16, 20 or 24 kg dry matter (DM)/cow for a 17 week period. On five occasions, at weekly intervals in the middle of the period, the three different milks were converted into low-moisture part-skim Mozzarella cheese. Increasing the DHA resulted in significant increases in the concentrations of protein in the cheesemilk (P < 0.05) and cheese whey (P < 0.02). The moisture-adjusted cheese yield increased significantly (P < 0.01) on raising the DHA from 16 to 24 kg grass DM/cow. DHA had no significant effects on any of the gross compositional values of the cheese (although moisture and fat-in-DM levels tended to decrease and increase respectively with increasing DHA). The hardness of the uncooked cheese and functionality of cooked cheese (i.e. melt time, flowability, stretch and viscosity) were not significantly influenced by DHA over the 115 d ripening period at 4 degrees C.

Animals↗
PubMed1998

Distinct time courses of word and context comprehension in the left temporal cortex.

The time course and cortical basis of reading comprehension were studied using magnetoencephalography. The cortical structures implicated most consistently with comprehension were located in the immediate vicinity of the left auditory cortex, where final words totally inappropriate to the overall sentence context evoked enduring activation starting approximately 250 ms and lasting up to 600 ms after word onset. Contextually appropriate but unexpected words produced weaker activation which terminated earlier. Highly anticipated words totally failed to activate this area, suggesting that the conceptual network became involved only if unexpected information was detected during the primary word identification process. We propose that the point in time (350 ms after word onset) where the response to appropriate but unexpected endings started to diverge from those to contextually inappropriate endings reflects the boundary between understanding a single word and the meaning of a whole sentence.

Adult↗
PubMed1998

Clinical use of marrow osteoprogenitor cells to stimulate osteogenesis.

This review of 15 years research into various methods and techniques of using marrow osteoprogenitor cells shows that marrow grafts can be useful for numerous skeletal healing problems, but not all. The method offers considerable improvement over standard open iliac crest grafting and provides an attractive and advantageous method of stimulating osteogenesis in the management and prevention of nonunion.

Animals↗
PubMed1998

Limb threatening neuropathic complications from ankle fractures in patients with diabetes.

Although less common than neuropathic (Charcot) deformities in feet, ankle deformities can occur and produce significant limb threatening complications after injury in patients with longstanding diabetes. A series of six such complications, including one that resulted in amputation and several near amputations, are presented. The authors' primary purpose is to alert or remind physicians and orthopaedic surgeons of the often unanticipated but significant complications of these rare and seemingly mild ankle injuries. A secondary purpose is to point out that complications may be avoided or mitigated with early stabilization and possibly with treatment of bone resorbing, inflammatory processes characteristic of neuroarthropathies.

Adult↗
PubMed1997

Individual differences in auditory middle latency responses in elderly adults and patients with Alzheimer's disease.

Previous research has suggested that the Pb component of the middle-latency auditory evoked response (MLAER) is differentially abnormal in patients with Alzheimer's disease relative to control subjects. In the present study, this putative abnormality was examined in vertex-recorded MLAERs elicited by monaural stimulation in 14 patients with Alzheimer's disease (six females) and 22 age-matched control subjects (10 females). A sex difference in Pb elicitation was revealed in control subjects; Pb area was twice as large in females than males (P < 0.05). Pb and Pa amplitudes and latencies did not differ between male and female control subjects. Comparisons of Pb between patients and controls were conducted within each sex. There was no main effect of group on Pb area, amplitude, or latency, Pa amplitude was significantly larger in patients than control subjects; there was no group difference in Pa latency. This study did not replicate previous reports of differences in Pb between patients with Alzheimer's disease and elderly control subjects. We demonstrated that Pb elicitation may be unreliable in elderly control subjects and found evidence of a possible sex difference. The effects of inter-subject variables (e.g. age, sex) must be understood more fully before MLAERs can be exploited as meaningful markers of brain dysfunction.

Acoustic Stimulation↗
PubMed1996

Effects of oxazepam and lorazepam on implicit and explicit memory: evidence for possible influences of time course.

The effects of oxazepam (30 mg), lorazepam (2 mg), and placebo on implicit and explicit memory were studied in two testing cycles, 100 and 170 min after drug administration. Thirty healthy volunteers were randomly assigned to one of three groups (placebo, oxazepam, or lorazepam) in a double-blind, independent groups design. Drug groups were equivalent prior to drug administration on a variety of cognitive measures. Following drug administration, both oxazepam and lorazepam equally impaired performance on a cued-recall explicit memory task relative to placebo, at both testing cycles. Relative to placebo, lorazepam markedly impaired priming on a word-stem completion implicit memory task, at both testing cycles. Consistent with previous work, oxazepam failed to produce impairments in priming on the word-stem completion task at 100 min post-drug administration. However, oxazepam was found significantly to impair priming on this latter task relative to placebo, at close to theoretical peak plasma concentration (i.e., 170 min post-drug administration). Explanations for the observed detrimental effect of oxazepam on implicit memory task performance are considered, including: possible time-dependent effects related to the relative rate of absorption of these two benzodiazepines (BZs); and potential contamination of the implicit memory task by explicit memory strategies during the second testing cycle.

Adolescent↗
PubMed1996

Evidence for multiple routes of speech production in a case of fluent aphasia.

A case study is reported of a 24-year old woman who developed fluent aphasia with superior reading relative to auditory comprehension following herpes simplex encephalitis. Her language disturbance showed exceptional features: oral reading, repetition and naming to confrontation were severely impaired and yet her spontaneous speech recovered to be relatively intact. These features are not consistent with Wernicke's aphasia, pure word deafness or any classic aphasic syndromes. These findings indicate the presence of several routes for phonological output that may be differentially impaired.

Adult↗
PubMed1995

The effects of phonological and semantic features of sentence-ending words on visual event-related brain potentials.

Event-related brain potentials (ERPs) were recorded to terminal words of visually presented sentences that were identical to those used in an auditory modality study examining the effects of phonological and semantic characteristics of words on ERPs (Connolly and Phillips, 1994). Phonological and/or semantic characteristics of terminal words were manipulated in 4 conditions in which: (1) the terminal word was the highest cloze probability ending for the sentence and was thus phonologically and semantically appropriate to the sentence context (e.g., Ray fell down and skinned his knee(s).; (2) the terminal word had the initial phonemic sound of the highest cloze probability sentence-ending word but was semantically anomalous to the context of the sentence (e.g., They sat together without saying a single worm. [word]); (3) the initial phoneme of the terminal word was phonologically unexpected but the word was semantically correct (e.g., The dough was put in the hot pan. [oven]); or (4) the initial phoneme of the terminal word was phonologically unexpected and the word was semantically inappropriate to the sentence context (e.g., Bill jumped into the lake and made a big farm. [splash]). A left fronto-temporally distributed negative peak was observed in the 250-300 msec range to varying degrees in all conditions but was largest in the condition in which terminal words were both phonologically unexpected and semantically inappropriate. A second, parietally distributed, symmetrical negativity (the N400) was found which peaked around 365 msec and was largest in the two conditions involving semantically anomalous terminal words. Results are discussed in terms of modality factors in ERP manifestations of receptive language functions and the implications of ERP modality differences for theories of word recognition.

Adult↗