BackgroundThe PACE trial was a well-powered randomised trial designed to examine the efficacy of graded exercise therapy (GET) and cognitive behavioural therapy (CBT) for chronic fatigue syndrome. Reports concluded that both treatments were moderately effective, each leading to recovery in over a fifth of patients. However, the reported analyses did not consistently follow the procedures set out in the published protocol, and it is unclear whether the conclusions are fully justified by the evidence.MethodsHere, we present results based on the original protocol-specified procedures. Data from a recent Freedom of Information request enabled us to closely approximate these procedures. We also evaluate the conclusions from the trial as a whole.ResultsOn the original protocol-specified primary outcome measure - overall improvement rates - there was a significant effect of treatment group. However, the groups receiving CBT or GET did not significantly outperform the Control group after correcting for the number of comparisons specified in the trial protocol. Also, rates of recovery were consistently low and not significantly different across treatment groups. Finally, on secondary measures, significant effects were almost entirely confined to self-report measures. These effects did not endure beyond two years.ConclusionsThese findings raise serious concerns about the robustness of the claims made about the efficacy of CBT and GET. The modest treatment effects obtained on self-report measures in the PACE trial do not exceed what could be reasonably accounted for by participant reporting biases.

The “tongue twister” paradigm is underutilizedas a research tool because so little is known abouthow it induces errors. The two experiments reported here explore this paradigm in detail using a task variationwhich minimizes articulatory and mnemonic load. This task was found to elicit good rates of apparently “pure” prearticulatory errors. Two of its features had a significant error-inducing effect: a) repeated reiteration; and b) the use of similar phonemes in targets (e.g., moss knife noose muff). The presenceof phoneme repeats (e.g., palm neck name pack) had no reliable overall effect, but did influence error distribution. Performance on the task differed in several ways from that observed on a control task with similar output demands, but no reiterative component. A model of the task is proposed, in which phoneme similarity and reiteration are seen as independent contributors to the task's error-inducing potential. Wider theoretical implications of certain results are also discussed.

No abstract

BACKGROUND: Publications from the PACE trial reported that 22% of chronic fatigue syndrome patients recovered following graded exercise therapy (GET), and 22% following a specialised form of CBT. Only 7% recovered in a control, no-therapy group. These figures were based on a definition of recovery that differed markedly from that specified in the trial protocol. PURPOSE: To evaluate whether these recovery claims are justified by the evidence. METHODS: Drawing on relevant normative data and other research, we critically examine the researchers' definition of recovery, and whether the late changes they made to this definition were justified. Finally, we calculate recovery rates based on the original protocol-specified definition. RESULTS: None of the changes made to PACE recovery criteria were adequately justified. Further, the final definition was so lax that on some criteria, it was possible to score below the level required for trial entry, yet still be counted as 'recovered'. When recovery was defined according to the original protocol, recovery rates in the GET and CBT groups were low and not significantly higher than in the control group (4%, 7% and 3%, respectively). CONCLUSIONS: The claim that patients can recover as a result of CBT and GET is not justified by the data, and is highly misleading to clinicians and patients considering these treatments.

We report an individual with Broca's aphasia (J.H.M.), who exhibited powerful lexical context effects in word production tasks. In an adjective-noun production task (Experiment 1), J.H.M.'s production accuracy decreased as the number of adjectives in the phrase increased (e.g., curly hair vs. long curly hair). In a picture pair naming task (Experiment 2), J.H.M.'s naming accuracy was high, but her naming latencies were abnormally delayed when pairs were semantically related (e.g., goat and pig). This pattern was not observed for older controls. In a computerized Stroop task (Experiment 3), J.H.M.'s naming latencies were abnormally prolonged in the conflict condition, relative to a baseline colour naming task. This effect was far in excess of that for controls. Finally, in a blocked cyclic naming task (Experiment 4), J.H.M.'s accuracy was poorer and her latencies slower when the pictures were semantically related than when they were unrelated, and this effect built up across successive presentation cycles. It was far in excess of that exhibited by older controls. We propose that J.H.M.'s pattern of impairment across these four very different tasks suggests an impairment to a lexical control mechanism, whose normal function is to modulate the flow of activation throughout the lexical network, so as to minimize the competitive effects of nontarget lexical items.

A recent theory of lexical access in picture naming maintains that all nonword errors are generated during the retrieval of phonemic segments from the lexicon (Dell, Schwartz, Martin, Saffran, & Gagnon, 1997b). This theory is challenged by "dual origin" theories that postulate a second, post-lexical mechanism, whose disruption gives rise to "phonemic paraphasias" bearing close resemblance to the target. We tested the dual origin theory in a corpus of 457 nonword errors drawn from 18 subjects with fluent aphasia. The corpus was divided into two parts, based on degree of phonological overlap between error and target, and these parts were separately examined for proposed diagnostic characteristics of the postlexical error mechanism: serial order effects across the word, sensitivity to target length, and insensitivity to target frequency. Results did not support the dual origin theory but were consistent with a single, lexical origin account in which segment retrieval operates from left to right, rather than in parallel. Findings from this study also shed new light on how individual differences in the severity of the retrieval deficit modulate the expression of phonological errors in relation to target characteristics.

No abstract

No abstract