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Biomedical subjects

J Rothwell

Publications and source records attributed to J Rothwell.

At least 19 recordsLinked to original sources
PubMed2006

Rapid assessment breast clinics--evolution through audit.

This observational, cohort study aimed to examine the potential utility of Rapid Assessment Breast Clinics (RABC) beyond cancer detection at presentation. One thousand four hundred and twenty nine women were studied over an 18 month period. 154 (10.7%) had breast cancer - 87.7% of whom were seen expediently with 92.9% being diagnosed at one attendance. One hundred and forty three (10%) of those with a benign diagnosis were found by routine questioning to have significant familial risk separate to their reason for referral. Despite careful triage, considerable contamination of appointment allotment occurred with many who were correctly triaged as non-urgent being seen 'urgently'. One hundred and seventy six attendees (12.3%) had neither the symptom that triggered referral, nor breast lump, nipple discharge nor family history of breast cancer, while 283 (19.8%) had no objective clinical or radiological abnormality. Although RABC reliably categorise malignant versus non-malignant diagnoses despite cluttering by low risk women, a significant proportion of non-cancer patients still require address of future risk rather than reassurance of their present status alone.

Adult↗
PubMed2005

Psychosocial needs of boys in secure care for serious or persistent offending.

BACKGROUND: The mental health of child offenders who are detained in secure settings is a matter of great public and professional concern but there has been little systematic longitudinal research on the outcomes of these problems once the young person has returned to the community. The aims of the present study were to describe the psychosocial outcomes of boys in secure care and to establish if these outcomes were correlated with criminal outcomes. METHOD: Prospective cohort study of 97 boys whose average age was 14 years when they were admitted to secure units in the North West of England. The boys were followed up on average 2 years later, when outcome data were obtained on 81/97 (83%) cases. The main outcome measure was a standardised assessment of mental health, social and educational needs obtained by interview with the young person and corroborated in most cases by information from informants. All data were then reviewed by experienced clinicians who made best-estimate ratings of need 'blind' to the findings from the first phase of the study. RESULTS: The average number of needs requiring an intervention at follow-up (mean=3.4, sd=3.0) was much lower than before admission to secure care (mean=8.2, sd=2.5) (mean difference 4.9 needs, 95% CI 4.0 to 5.7). Educational and occupational needs were particularly well dealt with. However, many mental health problems persisted or worsened. For example, 31% had a need for treatment of substance abuse, a significant increase compared with when they were in secure care (percentage difference 21%, 95% CL 9.0% to 32.7%). No mental disorder predicted subsequent offending. CONCLUSIONS: Boys who have been in secure care continue to have a high rate of mental health problems. The mental health needs of this group are not, however, static but change over time and with changing circumstances. Services need to be designed to meet these changing needs.

Adolescent↗
PubMed2005

Disturbances of grip force behaviour in focal hand dystonia: evidence for a generalised impairment of sensory-motor integration?

BACKGROUND: Focal task specific dystonia occurs preferentially during performance of a specific task. There may be an inefficiently high grip force when doing manipulative tasks other than the trigger task, possibly reflecting a generalised impairment of sensory-motor integration. OBJECTIVE: To examine how well subjects with writer's cramp (n = 4) or musician's cramp (n = 5) adapted their grip force when lifting a new object or catching a weight. METHODS: Nine patients with focal hand dystonia and 10 controls were studied. Experiments addressed different motor behaviours: (A) lifting and holding an object; (B) adjusting grip force in anticipation of or in reaction to a change in load force by catching a small weight dropped expectedly or unexpectedly into a hand held receptacle. RESULTS: In (A), patients produced a grip force overshoot during the initial lifts; force overflow was most pronounced in those with writer's cramp. Patients and controls adjusted their grip force to object weight within one or two lifts, though patients settled to a steady force level above normal. In (B), patients with focal hand dystonia and normal controls showed similar predictive grip force adjustments to expected changes in object load, suggesting that this aspect of sensory-motor integration was normal. Patients had a shorter latency of grip force response than controls after an unexpected load increase, reflecting either a greater level of preparatory motor activity or a disinhibited spinal reflex response. CONCLUSIONS: The overall increased grip force in patients with focal hand dystonia is likely to be a prelearned phenomenon rather than a primary disorder of sensory-motor integration.

Adult↗
PubMed2003

Slow frequency repetitive transcranial magnetic stimulation affects reaction times, but not priming effects, in a masked prime task.

OBJECTIVE: Slow frequency repetitive transcranial magnetic stimulation (rTMS) reduces motor cortex excitability, but it is unclear whether this has behavioural consequences in healthy subjects. METHODS: We examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 80% of active motor threshold) over left motor or left premotor cortex on performance in a visually cued choice reaction time task, using a 'masked prime' paradigm to assess whether rTMS might affect more automatic motor processes. Twelve healthy volunteers participated. RESULTS: Motor cortex rTMS and, to a lesser extent, premotor cortex rTMS resulted in a slowing of right (stimulated) hand responses, but not of left (unstimulated) hand responses. In a control experiment, rTMS of the left somatosensory cortex did not lead to slower right hand responses. DISCUSSION: We conclude that long trains of low intensity 1 Hz rTMS over the motor or premotor cortex can have subtle behavioural consequences outlasting the stimulation. rTMS did not affect the modulation of reaction times by subliminal primes, suggesting that priming effects triggered by subliminal primes are not generated at the level of motor or pre-motor cortex.

Adult↗
PubMed2002

Mental health needs of boys in secure care for serious or persistent offending: a prospective, longitudinal study.

BACKGROUND: The mental health needs of children and adolescents in secure care are a matter of concern, but little systematic research has been done. Our aim was to assess the mental health, social, and educational needs of these young people in a prospective, longitudinal study. METHODS: We enrolled 97 boys aged 12-17 years who had been admitted to secure care. We assessed their needs (n=97) at the time of admission and 3 months later (n=90) with standardised interviews and psychometric tests. RESULTS: 26 (27%) boys had an intelligence quotient (IQ) of less than 70. The need for psychiatric help was high on admission to a secure unit, with the most frequent disorders being depression and anxiety. There were high rates of aggression, substance misuse, self harm, and social, family, and educational problems, and associated needs. The mean number of needs was 8.5 (SD 2.9) on admission and 2.9 (SD 2.4) after 3 months (mean difference 5.6, 95% CI 5.0-6.3). Areas in which needs were mostly met included education, substance misuse, self care, and diet. Areas where the frequency of need fell substantially, but remained high, were social and family problems, and aggressive behaviours. Psychological needs persisted, with new onsets of depression, anxiety problems, and post-traumatic-stress symptoms shortly after admission. The most frequently required interventions were psychological assessment and cognitive behavioural work. INTERPRETATION: Boys in secure care have many needs and a high rate of psychiatric morbidity. During the admission period, secure care units address some domains of need, but others remain unchanged or get worse. Psychological and psychiatric provision in secure units need to be improved.

Adolescent↗
PubMed2001

Left posterior BA37 is involved in object recognition: a TMS study.

Functional imaging studies have proposed a role for left BA37 in phonological retrieval, semantic processing, face processing and object recognition. The present study targeted the posterior aspect of BA37 to see whether a deficit, specific to one of the above types of processing could be induced. Four conditions were investigated: word and nonword reading, colour naming and picture naming. Repetitive transcranial magnetic stimulation (rTMS) was delivered over posterior BA37 of the left and right hemispheres (lBA37 and rBA37, respectively) and over the vertex. Subjects were significantly slower to name pictures when TMS was given over lBA37 compared to vertex or rBA37. rTMS over lBA37 had no significant effect on word reading, nonword reading or colour naming. The picture naming deficit is suggested to result from a disruption to object recognition processes. This study corroborates the finding from a recent imaging study, that the most posterior part of left hemispheric BA37 has a necessary role in object recognition.

Adult↗
PubMed2001

Randomized trial of group therapy for repeated deliberate self-harm in adolescents.

OBJECTIVE: To compare group therapy with routine care in adolescents who had deliberately harmed themselves on at least two occasions within a year. METHOD: Single-blind pilot study with two randomized parallel groups that took place in Manchester, England. Sixty-three adolescents aged 12 through 16 years were randomly assigned to group therapy and routine care or routine care alone. Outcome data on suicide attempts were obtained without knowledge of treatment allocation on all randomized cases (62/63 by direct interview) on average 29 weeks later. The primary outcomes were depression and suicidal behavior. RESULTS: In intention-to-treat analyses, adolescents who had group therapy were less likely to be "repeaters" at the end of the study (i.e., to have repeated deliberate self-harm on two or more further occasions) than adolescents who had routine care (2/32 versus 10/31; odds ratio 6.3), but the confidence intervals for this ratio were wide (95% confidence interval 1.4 to 28.7). They were also less likely to use routine care, had better school attendance, and had a lower rate of behavioral disorder than adolescents given routine care alone. The interventions did not differ, however, in their effects on depression or global outcome. CONCLUSIONS: Group therapy shows promise as a treatment for adolescents who repeatedly harm themselves, but larger studies are required to assess more accurately the efficacy of this intervention.

Adolescent↗
PubMed2000

Organization of cortical activities related to movement in humans.

The extent and function of synchronization of oscillatory elements in the human sensorimotor cortex during movement remains unclear. Here we determine whether synchronization is distributed in both the spatial and frequency domains and whether it changes according to task. Electrocorticographic (ECoG) signals were recorded from presumed nonpathological areas simultaneously with electromyographic (EMG) signals from upper limb muscles during isometric and phasic movement tasks in humans with subdural electrodes in situ for investigation of epilepsy. Functional mapping of the sensorimotor cortex was performed by previous electrical stimulation through the same ECoG electrodes used for recording. Significant coherence between ECoG and EMG was seen at discrete frequencies in the range of 7-100 Hz. There was no predilection for coherence within a given frequency band to be associated with cortical sites that had been functionally defined as producing contralateral arm motor responses on stimulation. However, coherence with muscle in the 7-14 and 15-30 Hz band tended to be associated with ECoG sites that lay close to or within the central sulcus as determined intraoperatively. The spatial pattern and frequency of coherence changed with different tasks, although similarities in the coherence pattern remained for tasks that shared common features. These findings provide support for the hypothesis that that synchronization at specific frequencies links cortical activities into a functional ensemble during voluntary movement.

Arm↗
PubMed2000

Transcranial magnetic stimulation studies of cognition: an emerging field.

In this short review, we consider the application of transcranial magnetic stimulation (TMS) to the study of cognitive function. Following an introduction to the technique, we consider its possible mechanisms of action. We then review the studies that have applied TMS to the investigation of cognition. In the majority of these investigations, TMS has been applied to disrupt function and demonstrate that a particular cortical area is essential for performance of the task under study. Finally, we highlight pertinent design and procedural issues and consider other types of questions that can be addressed by future TMS studies of cognitive function.

Brain Mapping↗
PubMed2000

Transcranial magnetic stimulation in cognitive neuroscience--virtual lesion, chronometry, and functional connectivity.

Fifteen years after its introduction by Anthony Barker, transcranial magnetic stimulation (TMS) appears to be 'coming of age' in cognitive neuroscience and promises to reshape the way we investigate brain-behavior relations. Among the many methods now available for imaging the activity of the human brain, magnetic stimulation is the only technique that allows us to interfere actively with brain function. As illustrated by several experiments over the past couple of years, this property of TMS allows us to investigate the relationship between focal cortical activity and behavior, to trace the timing at which activity in a particular cortical region contributes to a given task, and to map the functional connectivity between brain regions.

Behavior↗
PubMed2000

Seroprevalence of Neospora caninum infection following an abortion outbreak in a dairy cattle herd.

OBJECTIVE: To investigate the seroprevalence of Neospora caninum infection in a commercial dairy cattle herd, 15 months after detection of an abortion outbreak. PROCEDURE: Sera from the whole herd (n = 266) were examined for N caninum antibodies by indirect fluorescent antibody test (IFAT) and immunoblot analysis. Herd records were reviewed to collate serological results with abortion history, proximity to calving, and pedigree data. RESULTS: The seroprevalence of N caninum infection was 24% (63/266) for IFAT titre > or = 160, 29% (78/266) for immunoblot positive (+ve), and 31% (82/266) for IFAT > or = 160 and/or immunoblot +ve; 94% (59/63) of animals with IFAT > or = 160 were immunoblot +ve. The association between seropositivity (IFAT > or = 160 and/or immunoblot +ve) and history of abortion was highly significant (P < 0.001); the seroprevalence was 86% (18/21) in aborting cows, compared with 30% (50/164) in non-aborting animals. The abortion rate for seropositive cows was 26% (18/68) compared with 3% (3/117) for seronegative animals. IFAT titres of infected cows were higher within 2 months of calving than at other times (P < 0.001). The association between seropositivity in dams and daughters was highly significant (P = 0.009). CONCLUSIONS: The abortions were associated with N caninum infection and there was evidence of reactivation of latent infection close to calving and congenital transmission of infection. Immunodominant antigens identified by immunoblots may prove useful for improved diagnostic tests.

Abortion, Veterinary↗
PubMed1999

On the focal nature of inhibition and facilitation in the human motor cortex.

OBJECTIVE: To find the area of the human cortex from which inhibition and facilitation of corticospinal neurons could be obtained. METHODS: A patient with seizures had an array of 64 electrodes placed over the left fronto-temporal cortex. The motor evoked potential (MEP) elicited by stimulating through one pair of electrodes was conditioned by stimuli that were subthreshold for a MEP given through adjacent pairs of electrodes. RESULTS: The MEP recorded over the right abductor pollicis brevis produced by stimulating over the hand area of the left cortex could be inhibited (at intervals less than 5 ms) and facilitated (at intervals greater than 5 ms) by subthreshold conditioning stimuli delivered through neighbouring pairs of electrodes. The inhibition and facilitation were only obtained when the conditioning stimuli were delivered within 1-2 cm of the test site. The sites producing inhibition and facilitation were not identical. Conditioning stimuli over the face area did not inhibit the MEP produced by stimulating the hand area or vice versa. CONCLUSION: The inhibition and facilitation of corticospinal neurons projecting to a given muscle arise from small areas close to those corticospinal neurons.

Electric Stimulation↗
PubMed1999

Reliability of the Salford Needs Assessment Schedule for Adolescents.

BACKGROUND: For adolescents, there is no specific needs assessment instrument that assesses significant problems that can benefit from specified interventions. A new instrument (S.NASA) was developed by incorporating and adapting three well established adult needs assessment instruments. The S.NASA covers 21 areas of functioning including social, psychiatric, educational and life skills. METHOD: Client and carer interviews were conducted by different researchers. A week later the interviews were repeated using a crossover design. Significant (cardinal) problems were generated from the clinical interviews using a pre-defined algorithm. Final need status (three categories) was made by clinicians assessing the cardinal problems against defined interventions. The interventions were generated from discussions with clinicians and a survey of appropriate professionals working with adolescents. RESULTS. Pre-piloting led to the final version being administered to 40 adolescents from secure units, forensic psychiatric and adolescent psychiatric services. There were 25 males and 15 females, mean age 15.5 years. Overall there were moderate to good inter-rater and test-retest reliability coefficients, the test-retest reliability coefficients for the total scores on the needs assessment interviews ranged from 0.73 to 0.85. Consensual and face validity was good, the adolescents and staff finding the instrument useful and helpful. CONCLUSIONS: This new needs assessment instrument shows acceptable psychometric properties. It should be of use in research projects assessing the needs and the provision of services for adolescents with complex and chronic problems.

Adolescent↗
PubMed1999

A cerebellar-like terminal and postural tremor induced in normal man by transcranial magnetic stimulation.

Trains of repetitive transcranial magnetic stimulation (TMS) at 10-30 Hz and intensities of 90-120% motor threshold were delivered through a figure of eight coil over the motor cortex while normal subjects made either rapid, self-terminated (ballistic) wrist movements or maintained the position of their wrist at a fixed angle. Movement kinematics and EMG activity in antagonistic forearm muscles were analysed. In the ballistic task, repetitive TMS had little effect on the velocity or acceleration of the initial segment of the movement, although it induced large terminal oscillations (tremor) around the target position at frequencies between 4.4 and 7.2 Hz. The likelihood that tremor would occur increased with increasing stimulus intensities or frequencies. It was maximal with stimulation over the forearm area, and decreased with stimulation over the leg area, or over parietal sites; there was no tremor during stimulation of cervical nerve roots. The frequency of the induced tremor was independent of the rate of stimulation and did not depend on the presence of excitatory and inhibitory motor responses to the stimulus. Stimulation could also induce tremor of the same frequency in the fixed task, but only during co-contraction of forearm muscles. The amplitude of tremor was proportional to the level of co-contraction. Clinically, the tremor induced by repetitive TMS appeared very similar to cerebellar tremors. In order to confirm this we investigated two cerebellar patients, one with autosomal dominant cerebellar ataxia and the other with multiple sclerosis. Both of them had a terminal tremor of 6-7 Hz in the wrist movement task. In the holding task, the amplitude of their postural tremor increased with the level of co-contraction in forearm muscles. Since the frequency of repetitive TMS-induced tremor was independent of stimulus parameters, we conclude that it represents some intrinsic property of the CNS. We suggest that the tremor is caused by disruption of cortical processes involved in terminating a voluntary movement or maintaining a posture. Similarities to cerebellar patients suggest that repetitive TMS may cause tremor by interfering with adaptive cerebellar afferent inflow to motor cortex. Repetitive TMS-induced tremor, therefore, may represent a model of some forms of cerebellar tremor in man.

Adult↗
PubMed1997

Changes in cerebral activity pattern due to subthalamic nucleus or internal pallidum stimulation in Parkinson's disease.

High-frequency electrical stimulation of the internal pallidum (GPi) or the subthalamic nucleus (STN) improves clinical symptoms of Parkinson's disease. In 12 parkinsonian patients, 6 with STN and 6 with GPi stimulators, we used H2(15)O positron emission tomography to evaluate whether changes in movement performance were accompanied by change in regional cerebral blood flow (rCBF). Patients were scanned both at rest and while performing a free-choice joystick movement, under conditions of effective and ineffective electrostimulation. During effective STN stimulation, movement-related increases in rCBF were significantly higher in supplementary motor area, cingulate cortex, and dorsolateral prefrontal cortex (DLPFC) than during ineffective stimulation. No significant change was observed in any of these areas during GPi stimulation. The difference between the effect of STN and GPi stimulation on movement-related activity was mainly localized to DLPFC. These results confirm the dominant role of nonprimary motor areas in the control of movement in parkinsonian patients and demonstrate the importance of STN input in the control of these areas.

Electric Stimulation↗
PubMed1997

Haemonchus contortus: the uptake and metabolism of closantel.

Closantel is an anthelmintic which associates with plasma albumin and is useful for the control of sheep parasites, such as Haemonchus contortus, that ingest blood. However, the utility of closantel for parasite control has been threatened by the emergence of resistance. The mechanisms of resistance are unknown. A closantel-resistant and a closantel-susceptible isolate of H. contortus were compared with respect to the distribution and metabolism of closantel. Neither strain appeared to metabolise closantel in vitro or in vivo. Following treatment of infected sheep with radioactively labelled closantel, isotope levels in closantel-resistant adult H. contortus were significantly lower than in susceptible worms. This reduced accumulation of drug could contribute to closantel resistance by mechanisms such as reduced feeding, failure to dissociate the drug-albumin complex in the gut or increased efflux of closantel from resistant worms.

Animals↗