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M R Ford

Publications and source records attributed to M R Ford.

At least 19 recordsLinked to original sources
PubMed1996

The effect of reference-electrode choice on the spatial resolution of topographical potential maps in the discrimination of deep cerebral sources.

Although scalp potential distributions do not uniquely determine the location and configuration of neural generators, they are important because they provide the necessary conditions that any hypothesized sources must satisfy and suggest a basis for testing alternate source hypotheses. One problem that could confound the correct interpretation of scalp potentials is the choice of reference electrode. Changing the reference may make activity patterns and waveform components appear and disappear (Pascual-Marqui et al. (1988) Int. J. Neurosci., 43: 237-249). The cortical imaging technique (CIT), a method for approximating potential fields on the cortical surface, was used to test the effects of the choice of reference electrode on these fields. Simulated and empirical evoked potential scalp-recorded referential data were mathematically analyzed for the case in which the reference (linked-ears) was arbitrarily assumed to be at zero potential, and the case in which the reference was the 'average' electrode, the arithmetic mean of all of the scalp-recorded voltages in the referential montage. The results for the two references were similar. This is encouraging because potential measurements relative to a point at infinity (zero potential) are never available and the assumption that any actual reference used for a recording is at zero potential is therefore suspect.

Animals↗
PubMed1994

Optimal electrode placements for adequate spatial sampling of auditory evoked potentials.

When evoked responses are used in clinical practice and research the measures that are most commonly considered are the latencies and amplitudes of EP components as measured at a single electrode site. Our recent studies have shown that multichannel recordings yield measures such as potential field asymmetry that may be as important as component latency and amplitude. The purpose of this short technical note is to suggest that electrode placement is critical for demonstrating interesting features of the potential field topography, specifically, bilateral, homologous generator sites. The cortical imaging technique (CIT) was used to analyze the averaged responses for a group of thirty normal young adults to a repeated tone and a random oddball tone. Recordings were obtained at 28 scalp recording sites which included 20 placements from the 10-20 system and eight additional sites. Simulated cortical maps were derived for four components, the N1 frequent response and the N2a, P3, and N3, rare minus frequent responses for three different electrode arrays. These arrangements included the full 28-channel array, a 20-channel array that excluded eight additional central sites, and a 20-channel array that included the eight additional sites and excluded peripheral sites. This study demonstrates that for these auditory paradigms, the placement of the electrodes is critically important for discriminating important features of the potential fields.

Acoustic Stimulation↗
PubMed1993

Spatio-temporal progression of the AEP P300 component using the cortical imaging technique.

The cortical imaging technique (CIT), a mathematical method for simulating the potential fields on the surface of the brain, was used to analyze the spatio-temporal progression of the AEP P300 component (as well as the preceding and subsequent N2a and N3 components) from thirty normal adult subjects recorded in a standard "oddball" paradigm. Comparisons were made between the progressions of the endogenous event-related cognitive potentials and the exogenous stimulus-dependent potentials (N1 component). Cortical imaging results suggest that different and multiple generator sites are involved in the production of exogenous and endogenous evoked responses. We particularly note the asymmetric development of the P300 component and the apparent anterior generator sites for the N2a component. This last result is interesting because the N2a precedes the P300 component and supports an earlier frontal contribution.

Adult↗
PubMed1991

Age-related features of the resting pattern-reversal visual evoked response using the dipole localization method and cortical imaging technique.

Two mathematical techniques, the dipole localization method (DLM) and the cortical imaging technique (CIT), are used to analyze the resting visual response to pattern-reversal stimulation. These methods identify certain age-related features of this evoked response that are not found by using standard topographic maps. These features include the symmetry of the N1 and P1 responses. The amplitudes of the N1 and P2 responses and the latency of N2 are also significantly different between old and young groups of test subjects, findings consistent with differences seen in conventional topographical analyses. Theoretical dipole sources and simulated cortical surface maps are also constructed for the "average" normal older subject and one patient with documented progressive frontal lobe degenerative disease. Standard topographical imaging studies of this patient were unremarkable, except for the P300 auditory response. DLM and CIT analyses of the VER components were exceptional and consistent with the clinical diagnosis. These mathematical methods appear to enhance the discriminating power of traditional electrophysiological measures.

Adult↗
PubMed1990

Age-related features of the resting and P300 auditory evoked responses using the dipole localization method and cortical imaging technique.

Two mathematical techniques, the dipole localization method (DLM) and the cortical imaging technique (CIT), are used to analyze the resting and P300 auditory responses in young and old normal volunteers. These methods identify certain age-related features of these evoked responses that are not found by standard topographic methods. These features include the orientation of the P200 resting response, and the laterality of the N120 response, and the eccentricity of the P300 response in the P300 stimulus condition. Theoretical dipole sources and simulated cortical surface maps are also constructed for one normal subject and one psychiatric inpatient and compared. These mathematical methods appear to enhance the discriminating power of traditional electrophysiological measures.

Adult↗
PubMed1989

Sex bias in the diagnosis of histrionic and antisocial personality disorders.

The differential prevalence of the histrionic and antisocial personality disorders among men and women has been attributed both to sex biases and to actual variation in disorder base rates. The present study assessed the bias and base rate explanations and examined whether sex biases are minimized by the relatively explicit diagnostic criteria in the DSM-III. Psychologists (N = 354) either diagnosed 9 DSM-III disorders from case histories that varied in the ambiguity of the antisocial and histrionic personality disorder diagnoses or rated the degree to which specific features extracted from the case histories met 10 histrionic and antisocial diagnostic criteria. The sex of the patient was either male, female, or unspecified. Sex biases were evident for the diagnoses but not for the diagnostic criteria. The results are discussed with respect to base rate effects, sex biases, and the construction of diagnostic criteria.

Adult↗
PubMed1986

EEG coherence and power in the discrimination of psychiatric disorders and medication effects.

Electroencephalogram (EEG) coherence (COH) and power measures were included in a series of stepwise discriminant analyses to determine which variables were most sensitive in the differentiation of four psychiatric inpatient groups and two major classes of psychotropic medication. Eight channels of eyes-closed, bipolar EEG activity were recorded from 74 inpatients (paranoid schizophrenics, dysthymics, major affectives receiving tricyclics, neuroleptics, or no medication, and geriatrics). Discriminant analyses were conducted for theta, alpha, and fast beta frequency bands for power variables, COH variables, and the resultant significant power and COH discriminating variables. Without exception, COH measures, usually in the alpha band, were more sensitive than power measures in differentiating the various groups. Results suggested that COH decreases with age, is greatest in paranoid schizophrenics, decreases with neuroleptic medication, and increases with tricyclic antidepressants. Group differences were interpreted in accordance with an arousal model for COH.

Affective Disorders, Psychotic↗
PubMed1986

EEG coherence and power changes during a continuous movement task.

EEG coherence (COH) is a mathematically derived measure of the time- and frequency-related similarities between a pair of EEG channels. In this report, COH was measured during an externally verified motor task in which the areas of cortical involvement are known, with special consideration given to procedural and artifactual issues. Fourteen right-handed women (ages 18-39, means = 26.7 years) were instructed to alternate continuously between fist-clenching and finger extension of the right hand, left hand, both hands, or neither hand (rest condition) in a counter-balanced sequence (4 one-minute trials for each condition; 16 total minutes). One minute each of intentional eye-movement (EOG) and intentional facial muscle tension (EMG) was recorded for artifact assessment. Eight channels of eyes-closed EEG were recorded from Fp1, Fp2, F3, F4, C3, C4, P3 and P4, each referenced to the ipsilateral earlobe. FFT spectral power analyses were conducted on 8 EEG channels and COH analyses (percentage of seconds/minute in which COH greater than or equal to 0.80) were performed on 16 pairs of leads: 4 interhemispheric, 6 intrahemispheric (left) and 6 intrahemispheric (right). COH measures increased during hand movement conditions, especially in the 9-12 Hz range, and were most apparent from prefrontal, premotor and motor areas. Parietal sources were essentially unchanged. Power measures were unchanged for virtually all leads and conditions. Increases in COH were not due to EOG or EMG artifact contamination. Evidence for lateralized increases was equivocal; significant bilateral increases were observed more often regardless of the hand clenched. Implications and suggested areas for future research are discussed.

Adolescent↗
PubMed1985

Interpersonal stress and style as predictors of biofeedback/relaxation training outcome: preliminary findings.

Although the data base describing clinical outcome following biofeedback/relaxation training is accumulating, there have been relatively few attempts to predict short-term outcome, and even fewer for long-term outcome. Significant short-term outcome predictors have been identified, and they often allude to the level of psychological distress as a major factor affecting outcome. To investigate further the role of psychological variables in outcome prediction, this project presents preliminary findings that demonstrate the relationship involving interpersonal psychological stress, interpersonal style of behavior, and outcome. With a very heterogeneous group of patients (N = 39), measures of interpersonal style of behavior were used to discriminate correctly 80% of cases by outcome at the 3-month postadmission evaluation. With a more homogeneous group having somatic disorders alone (headache, Raynaud's, etc.), the accuracy of prediction at 3 months was 90%. No measures were capable of predicting long-term outcome with accuracies even moderately greater than chance. The results indicate that style of interpersonal behavior (e.g., managerial, dependent) and, to a lesser extent, interpersonal stress is predictive of short-term outcome following biofeedback/relaxation training. Individuals who tend to like responsibility and who are more executive and independent generally benefited more than doubtful, obedient, and depressed individuals. While the resulting prediction rates were only slightly more accurate than MMPI D and Pt subscales alone, the procedures provide additional information regarding the personality characteristics of successful and unsuccessful biofeedback clients, and may also provide the clinician with information regarding treatment choice if biofeedback is provided as an adjunct to psychotherapy.

Adult↗
PubMed1983

Quieting response training: predictors of long-term outcome.

Extensive personality, demographic, and symptom-related information from a heterogeneous group of more than 300 patients was examined for patterns that would discriminate between successful and unsuccessful outcomes in patients undergoing Quieting Response (QR) training, an 8-week program that integrated EMG and thermal biofeedback with a variety of relaxation exercises. Follow-up evaluations were at 3, 6, 12 and 24 months. Agreement between expected (from stepwise discriminant analyses) and observed outcomes was 65% (whole sample), 62% (headache only), and 70% (Raynaud's only). Unimproved patient MMPI scales D, Sc, F, Hy, and Pt were significantly elevated. A variety of additional measures used indicated elevated levels of psychological stress among unsuccessful patients. While stereotypical descriptions of successful and unsuccessful patients are proposed, patterns from outcome groups were more similar than dissimilar, and no combination of factors was identified that had sufficient predictive power for use with future patients. No statistical grounds for exclusion were found among patterns of responses to the measures employed. Factors contributing to the inaccuracy of outcome prediction are discussed.

Biofeedback, Psychology↗
PubMed1983

Quieting response training: long-term evaluation of a clinical biofeedback practice.

Clinical evidence for the long-term effectiveness of biofeedback related relaxation training is accumulating. The purpose of this report is to describe the population, self-regulation procedure, outcome criteria, and final outcome for patients who received Quieting Response (QR) training. Data from 340 patients who completed at least the first follow-up at 3 months is presented. Primary presenting symptoms were headaches, 72%; primary and secondary Raynaud's, 14%; hypertension, 4%; irritable colon, 4%; and miscellaneous, 6%. QR training integrated EMG and thermal feedback with deep breathing, progressive relaxation, and autogenic exercises presented on cassette tapes. Eight 1-hour weekly sessions were given, with emphasis on daily home exercises. Follow-up evaluations were at 3 months, 6 months, 1 year, and 2 years. Outcome was based on change in frequency, severity, and duration of symptoms; changes in medication; and secondary benefits. Quieting Response training was found to be most beneficial for patients with primary Raynaud's disease (18 of 23 patients, or 78% successful), classic migraines (9 of 13, or 69%), and common migraines (20 of 32, or 62%), followed by mixed headaches (79 of 131, or 60%), Raynaud's plus other symptoms (9 of 15, or 60%), and the irritable colon syndrome (7 of 13, or 54%). Less successful were patients with headaches plus other symptoms (16 of 37, or 43%), muscle contraction headaches (13 of 33, or 39%), secondary Raynaud's phenomenon (4 of 10, or 40%), and essential hypertension (5 of 15, or 33%). Speculations about the differing outcomes across symptom groups were made.

Adult↗
PubMed1982

Biofeedback treatment for headaches, Raynaud's disease, essential hypertension, and irritable bowel syndrome: a review of the long-term follow-up literature.

Long-term follow-up evidence for biofeedback treatment of headaches, Raynaud's disease, essential hypertension, and the irritable bowel syndrome was reviewed. Acknowledging the difficulties with cross-study comparisons, the following general success rate were determined: primary idiopathic Raynaud's disease--70%, or better; vascular headache--70%, or better; mixed headache--about 60%; and muscle contraction headache--50%, or less. With relatively fewer patients, successful outcomes with the irritable bowel syndrome and secondary Raynaud's phenomenon were roughly 60% and 40%, respectively. Few cases of clinically significant long-term decreases in diastolic blood pressure were demonstrated; however, the need for medication was reduced or eliminated in some patients. There were indications that biofeedback combined with psychotherapy resulted in highest success rates. No differences were found in effectiveness between biofeedback, other relaxation techniques, and biofeedback in combination with relaxation techniques--all had essentially comparable rates of success. No correlations between physiological and psychological measures of condition at follow-up were reported. Implications and interpretations of these findings are discussed.

Biofeedback, Psychology↗
PubMed1982

Quieting response training: treatment of psychophysiological disorders in psychiatric inpatients.

Self-regulation methods incorporating biofeedback are known to be useful in the treatment of psychophysiological disorders in psychologically normal patients. In this study, the effectiveness of Quieting Response (QR) training for the treatment of secondary psychophysiological complaints in psychiatric inpatients was assessed. Ten male and 27 female inpatients with a variety of secondary psychophysiological diagnoses were accepted into the study. Severely disturbed, confused, or depressed patients were excluded. All patients received QR training, which integrated EMG (electromyogram) and thermal feedback with breathing, progressive relaxation, and autogenic exercises. Daily practice of a 15-minute sequence of exercises was encouraged, and a 6-second reinforcement exercise was presented for use whenever an annoyance was encountered. No other therapeutic modalities were employed. Patients were followed for up to 2 years, and outcome was assessed with a multifactor quartile system. Rate of success at final follow-up for the inpatients (51%) was found to be equivalent to that of outpatients coming to the clinic with primary psychophysiological diagnoses (55%) and was not related to psychiatric diagnosis or nature of presenting complaint. Stepwise discriminant analysis indicated that older, less depressed individuals were more successful. Inpatients differed from nonpsychiatric patients only in the number of additional sessions received. Only one minor incident of increased psychopathology was observed. It was concluded that QR training was as effective for treating secondary psychophysiological disorders in all but the most severely disturbed inpatients as it was for the outpatient clinic population.

Adult↗
PubMed1982

A clinically useful polling technique for assessing susceptibility to motion sickness.

Susceptibility to motion sickness is a powerful index of individual differences and can be assessed in large populations without a test of performance. Although all questionnaire techniques introduce some error, we have demonstrated that a simple set of questions can lead to a five-point rating system with adequate validity and reliability. Our observations may be useful to any investigator interested in individual differences and have been extremely effective in sorting out behavioral trends in large samples of patients.

Female↗