Temperature & Multiple Sclerosis

Moderate hypothermia (33 degrees C) was induced for 7 and 3 days, respectively, in two patients with Multiple Sclerosis.

In both patients, striking improvement of clinical signs persisted throughout the period of cooling, indicating the potential for sustained reversal of the Neurologic deficit.

Hypothermia may aid management of severe acute exacerbations of Multiple Sclerosis.

Our objective was to investigate how cooling of the arm and vision influence pointing movements in healthy subjects and patients with Cerebellar limb Ataxia due to clinically proven Multiple Sclerosis.

An infrared video motion analysis system was used to record the unrestricted, horizontal pointing movements toward a target under three different conditions involving a moving, stationary, or imaginary target; a visual, or acoustic trigger; and vision or memory guidance.

All three tasks were performed before and after cooling the arm in ice water. Patients had more hypermetric and slower pointing movements than controls under all tested conditions.

Patients also had significantly larger three-dimensional finger sway paths during the postural phase and larger movement angles of the wrist joint.

Memory-guided movements were the most hypermetric recorded in both groups.

Cooling of the limb had no effect on amplitude or peak velocity of the pointing movement in either group under all tested conditions.

But, significantly reduced the three-dimensional finger sway path during the postural phase in patients with limb Ataxia.

Cooling-induced reduction of the finger sway was largest in those patients with the largest finger sway before cooling.

In conclusion, the cooling-induced reduction of the Proprioceptive afferent inflow, most probably of group I spindle afferents, reduces Postural Tremor of patients with Cerebellar Dysfunction.

Upper Limb Ataxia is one of the most disabling symptoms of patients with Multiple Sclerosis (MS).

There are some clinically tested therapeutic strategies, especially with regard to Cerebellar Tremor.

But most of the methods used for treatment of Limb Ataxia in PhysioTherapy and Occupational Therapy are not systematically evaluated, e.g. the effect of local ice applications, as reported by MS patients and therapists, respectively.

We investigated 21 MS patients before and in several steps 1 up to 45 min after cooling the most affected forearm.

We used a series of 6 tests, including parts of Neurological status and activities of daily living as well.

At each step skin temperature and nerve conduction velocity were recorded. All tests were documented by video for later offline analysis.

Standardized evaluation was done by the investigators and separately by an independent second team, both of them using numeric scales for quality of performance.

After local cooling all patients showed a positive effect, especially a reduction of Intentional Tremor. In most cases this effect lasted 45 min, in some patients even longer.

We presume that a decrease in the Proprioceptive afferent inflow-induced by cooling-may be the probable cause of this reduction of Cerebellar Tremor.

Patients can use ice applications as a method of treating themselves when a short-time reduction of Intention Tremor is required, e.g. for typing, signing or self-catheterization.

We tested the hypothesis that reducing core body temperature in subjects with Multiple Sclerosis (MS) improves the Cortical SomatoSensory Evoked Potential (SEP) response.

Twenty subjects with Definite MS were compared with 20 subjects without Neurologic symptoms or disease. SEPs were recorded with stimulation of the Tibial and Median Nerves unilaterally at 3.1 and 6.1 Hz.

The procedure was repeated after a cooling vest and hat reduced core body temperature by an average of 0.46 +/- 0.28 degrees C.

No appreciable change in latency or amplitude of the SEP responses occurred in either the control or MS group with cooling.

Although the amplitude of the Cortical SEP response was less at the 6.1 Hz rate than at 3.1 Hz, there were no statistically significant differences between the MS and control groups or between stimulation rates with cooling.

We conclude that, although some reports suggest symptomatic improvements during cooling in subjects with MS, this improvement may not be associated with changes in the SEP.

Personal cooling systems are used to alleviate symptoms of Multiple Sclerosis and to prevent increased core temperature during daily activities.

The objective of this study was to determine the operating characteristics and the physiologic changes produced by short term use of one commercially available thermal control system.

A Life Support Systems, Inc. Mark VII portable cooling system and a liquid cooling helmet were used to cool the head and neck regions of 12 female and 12 male subjects (25-55 yr) in this study.

The healthy subjects, seated in an upright position at normal room temperature (approximately 21 degrees C), were tested for 30 min with the liquid cooling garment operated at its maximum cooling capacity.

Electrocardiograms and scalp and IntraCranial blood flows were recorded periodically during each test sequence.

Scalp, right and left ear, and oral temperatures and cooling system parameters were logged every 5 min.

Scalp, right and left ear canal, and oral temperatures were all significantly (P <0.05) reduced by 30 min of head and neck cooling.

Oral temperatures decreased approximately 0.2-0.6 degrees C after 30 min and continued to decrease further (approximately 0.1-0.2 degrees C) for a period of approximately 10 min after removal of the cooling helmet.

IntraCranial blood flow decreased significantly (P < 0.05) during the first 10 min of the cooling period.

Both right and left ear temperatures in the women were significantly lower than those of the men during the cooling period.

These data indicate that head and neck cooling may be used to reduce core temperature to that needed for symptomatic relief of both male and female Multiple Sclerosis patients.

This study quantifies the operating characteristics of one liquid cooling garment as an example of the information needed to compare the efficiency of other garments operated under different test conditions.

A cooling system (Mark VII Microclimate System) was used to give six ThermoSensitive Multiple Sclerosis patients two 45-minute daily coolings for a period of one month.

Before the first cooling, a baseline clinical and ElectroPhysiological examination was performed.

The same tests were repeated after the first application and after the thirtieth cooling day, thus providing information relating to acute and chronic efficacy.

A clinical improvement was observed after both acute and, more unexpectedly, chronic cooling, whereas a significant improvement in Central SomatoSensory Conduction was recorded only under acute conditions.

Our data suggest that cooling with this device leads to an improvement in some functional performances (mainly Fatigue and strength) of about two hours' duration in ThermoSensitive patients.

An Uhthoff-like phenomenon was recently observed in a patient with Clinically Definite MS who experienced transient Dysphonia brought on by exertion and relieved by cooling.

The patient's Dysphonia was felt to be related to intermittent temperature-dependent Conduction Block associated with a DeMyelinating plaque in the region of the left Nucleus Ambiguus.

We have termed the patient's Intermittent Dysphonia 'Laryngeal Uhthoff's Phenomenon'.

An 8-year-old girl with DeMyelinating Peripheral Neuropathy was observed to get markedly weak coincident with a febrile illness.

With return of body temperature to normal over 24 hours, her strength improved back to baseline.

Subsequently, we studied the effect of temperature on CMAP amplitude of two Motor Nerves in the patient and two control subjects.

Both temperature, measured orally, was raised by immersing the subjects in hot water and lowered by passive cooling.

With increase in temperature to 39.5 degrees C, the CMAP amplitudes were reduced by 80% in the patient's nerves compared to only 48% in the control nerves. These changes recovered with cooling to 36.9 degrees C.

We conclude that DeMyelinated Peripheral Nerves are more susceptible to temperature-induced impulse blocking than healthy nerves.

And provide the first published evidence of the clinical consequences of this phenomenon in a DeMyelinating disease other than Multiple Sclerosis.

Comments:

• Muscle Nerve 1995 Jun;18(6):674-5

The Uhthoff Symptom, a transient impairment of Visual function after exercise, is demonstrated in 2 Multiple Sclerosis patients.

Following exercise, impairment of Visual function, as documented most clearly by the testing of contrast sensitivity, was less obvious after body surface cooling and after treatment with orally administered 4-AminoPyridine.

It is hypothesized that both treatment modalities improve the Nerve conduction safety factor and thereby prevent the occurrence of a Conduction Block, which is believed to be the mechanism underlying the Uhthoff Symptom.

Symptomatic Fatigue has not been investigated previously in a Multiple Sclerosis population.

Potential subjects were the 78% of 656 individuals with Multiple Sclerosis who indicated in a previous study that they experienced symptomatic Fatigue.

Three hundred nine subjects (60%) returned a follow-up questionnaire on symptomatic Fatigue.

Ninety percent described Fatigue as "tiredness or the need to rest," but 43% of them indicated that "sleepiness" was part of the symptomatology.

In 48% Fatigue made other MS symptoms worse. Fatigue tended to occur in the late afternoon and evening. It occurred almost daily for more than 66% of the subjects.

In 47% of the subjects Fatigue usually subsided within a few hours; in other subjects occurrences were of variable length (40%) or lasted between 6 and 24 hours (8%).

Ninety percent said that Fatigue was worse at warmer environmental temperatures.

Fatigue was worse for 83% after "vigorous exercise" and for 64% after "moderate exercise" although 15% reported that moderate exercise helped to reduce Fatigue.

Meditation, some drugs, and cooling with water reduced Fatigue in a majority of the small proportion of the population trying these techniques.

A planned daily schedule of activity and rest seemed to be a partially effective response to symptomatic Fatigue for the majority of subjects studied.

Negative effect of thermal procedures (hot bath taking or intake of 1-2 glasses of hot water) was established while examining 105 patients with Disseminated Sclerosis.

The patients' status worsening was marked also during sharp cooling, whereas improvement during moderate cooling without shivering.

A definite diagnostic significance of thermal procedures in Disseminated Sclerosis is pointed out.

Aggravation of Neurological symptoms in MS patients in heating is well known. This phenomenon is explained by the change of conduction in DeMyelinated Nerve Fibers.

In raised temperature Conduction Block occurs. The Threshold of Conduction Block dependent on temperature, is probably proportional to the degree of DeMyelination.

It is possible to inhibit this effect by Tyrosin.

This model may present a view to a part of NeuroPhysiological mechanisms of MS, on which we possibly can take therapeutical influence.

By way of a questionnaire 125 MS patients were asked about changes of their symptoms in heating or cooling.

93% had marked sensitivity to heating. In 90% worsening of Neurological symptoms or of general feeling occured in a hot bath.

On the other hand about half the patients reported improvement in a cold bath.

Therefore we suggest, that a noticeable part of Neurological Deficit is reversible, if we were able to raise the threshold of Conduction Block, which depends on Temperature, PH, Electrolytes and NeuroTransmitters.

Seven Multiple Sclerosis patients were cooled and four heated, but Evoked Potential delay changed in only five out 11 experiments. Control limits were set by cooling eight and heating four control subjects.

One patient gave anomalous results in that although heating degraded perceptual delay and Visual Acuity, and depressed the sine wave grating MTF, double-flash resolution was improved.

An explanation is proposed in terms of the pattern of Axonal DeMyelination.

The medium frequency flicker Evoked Potential Test seems to be a less reliable means of monitoring the progress of DeMyelination in Multiple Sclerosis patients than is double-flash campimetry or perceptual delay campimetry.